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Hobbyist Renewable Energy?
vossman77 writes "I was looking into renewable energy from a hobbyist perspective, maybe generating a few watts of solar or wind power, just to reduce my electric bill. But upon further review, I found out that I need a special grid-tied AC inverter that shuts off when the grid turns off (for worker safety reasons) and makes the current in-phase with the grid. These two additional features, over the cheap inverters sold at department store, make the cost upwards of $2000, but support more watts than I need. While this is fine for large-scale projects, it is out of range for a small scale hobbyist. A Google search came with some home-brew hacks at best. So, are there any Slashdotters out there doing small-scale renewable energy projects with grid-tied systems? What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?"
What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?
Breed Whales, burn the oil.
which is totally what she said
use an induction motor as used in commercial windmills
Induction motors can be used as generators
and they automatically shut down when grid is down.
You can try converting parts of your house to 12 or 24 volt, which would negate the need for expensive inverters and whatnot. All you'd need is a simple charging circuit for a battery (could be as simple as a diode) and then feed the 12/24 volt lights straight off it.
Feed the need: Digitaladdiction.net
If your house isn't worth $2000 then go a head jury rig something (that would probably cause your house to burn down and void your insurance to boot). Else stop screwing around, pay the $2000 and get the parts you need to do this sort of work.
Electricity is a dangerous thing, jury rigging solutions is not an option when your safety is at risk. The device is $2000 because it must pass safety, UL, and a whole host of standards so it doesn't you know kill you or blow up the local transformer when somthing goes wrong.
Whenever you're going on solar, you throw a switch that cuts off mains and cuts in the solar (or whatever).
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The easy way is just to find some subset of your electrical appliances, and arrange them with a switch, to be supplied by either your own electricity, or the grid. This is trivial to do manually, and can be automated with a relay. The downsides are:
- at the moment of switchover, your appliance gets cut off.
- you are always wasting some or all of your power - assuming that both supply and demand vary, and the switching is granular.
To some extent, you can improve on this by using a UPS downstream of your switch.
This isn't exactly an "efficient" solution, but it will work, and it's simple and cheap.
I imagine anything you want to hook up to the grid will need to be regulated, approved and expensive. So, the alternative is a power source large enough for a single task, like running your computer, and a hefty UPS to carry you through shady spots. Plus an automatic switch over to grid power for when your batteries run down.
http://www.otherpower.com/
Sorry, a home brew solution won't cut it. The power company won't allow a non-certified piece of equipment to be hooked up, nor will your homeowners insurance. The liabilities are simply not worth the savings.
"To those who are overly cautious, everything is impossible. "
If you don't want to tie-into the grid, the easiest option would be to have a circuit that is powered by your renewable source. Put things on that circuit to use about the same energy that your source would produce over a day, and make sure you have enough storage (lead acid batteries) to store 2 days worth of energy at regular load.
At the hobby level, set up a recharging station with a small solar panel, controller and a small 12 volt gel battery for all of your battery driven devices. Cell phones, laptops, quick recharge AA and C batteries. Save a few bucks and be prepared in the event of emergencies or grid brownouts that the Utilities seem to suggest may be coming in the near future unless rates are hiked.
Good Luck
Why not just run a separate line using roaming wire to wherever you'd want the juice? I see no reason to tie it back into your regular electricity. That way you can use the cheap inverter plus whatever storage you want and power up select electronic devices. I have a friend who does just that with a home made solar panel on his garage roof. He uses it to power his laptop & lights in his man-cave during the summer. Just be sure to be safe and not overload the wires.
If going green was cheap, fossil fuels would die out on their own without incentives and subsidies.
You don't have to grid-tie to have solar power.
You could run the energy to a bank of batteries.
Does this mean your whole house is powered? No, but you could run quite a few things off of that bank of batteries, like a PC: http://www.tomshardware.com/reviews/hardware-components,1685.html
Keep it simple and separated. Also, DC power at 12V is much simpler and cheaper to generate and good enough for RV style lighting fixtures.
To generate 12V DC to charge a car battery, get a 24V or 36V cooling fan for a stationary motor (for something like a large industrial compressor) and mount it on a post. Add a big diode and hook it to the battery. Simple as that.
Excuse me, but please get off my Pennisetum Clandestinum, eh!
You really don't need the grid tie if you just want to (completely) isolate one circuit in your house, and run that solar and batteries and do-dads, etc. Other options, how about those electric lawn mowers? You could keep one of those charged up. You can keep some deepcycle batteries charged for use when the power goes out (I do this myself), run your laptop with a car adapter and the radio and some 12 VDC lights, whatever. You can get some *really spiffy* efficient food freezers now that are designed to run from one good panel. http://www.sundanzer.com/ -that is a "cool" idea methinks. Practical.
You don't tie into their grid, THEY tie YOU into THE GRID.
The fact that the grid inverter shuts off when the grid shuts off makes this a poor backup power solution. You should use a transfer switch to isolate the backup power source from the grid to use it if the grid is down.
The consequence of doing things like that without permits and/or inspection is that on the off chance that there was ever a problem, you'd be financially liable for any consequences.
There are opportunities to do strictly off-grid stuff, or at least you could keep to the low-voltage side of things. If you have a UPS for your computer or phone/router infrastructure, you could put up a solar panel to keep the standby battery charged. To the extent that the system runs off of DC power, you could supplant the power drawn from the grid with a panel, and reduce your electrical footprint that way.
Less is more.
My main cost for electricity is the Air conditioning system. Conveniently enough, I am in California, so I only need A/C when the sun is out, this makes it a perfect project for a closed solar system.
My house is grid tied, but my wall unit Air conditioner (and roof vents, and 2 of the outlets on my porch) are 100% real time solar (with no batteries capacitors), in their own closed circuit, which is not at all grid tied. So, basically I cool my house for free, and it cost less than $1000 for everything (panels, raw materials to do the wiring myself).
My next step is to get an outlet in the kitchen to run my next worse appliance that only needs to run part time: The washing machine, then The Dishwasher.
Like the OP mentioned, this is a hobby thing just as much as a "green" or "money saving" thing, so I found the approach of taking the low hanging fruit (electricity I NEED to use only during the sunny time) was a favorable approach over using batteries, and expensive grid-tied adaptors/regulators/converters.
Any inverter you get should be in phase with the grid, since that's the type of power expected by your appliances. If you mean pure sine wave 60hz, that's not needed. The grid power isn't that clean. It's nice to have for battery systems, though. It'll keep your appliances quieter. That's probably your best bet is going with an off-grid RV/cabin inverter with a basic battery system. That's sill going to cost quite a bit, though. Generally speaking, a grid-intertie inverter is cheaper than batteries, but That's for larger systems, I'm not sure how the prices scales on the low end.
It's not electrical, but solar hot water heating (with a storage tank that feeds into your main water heater) is certainly something that you can use your "hobbyist" skills to save money, that you can put together with a couple hundred dollars and some plumbing skills and basic wiring (pump & temperature switch). It can save you a bunch of money, whether or not you use electric or gas to heat your water currently.
Just reducing how much electricity you use. That's free and easy.
Or - buy and energy efficient appliance. That will probably save you more electricity than any rinky dink solar system you set up.
Just don't hook to the grid. Keep a stack of DC devices like say.. a PC, lighting, refrigerator, LCD, etc that are powered off of battery when the sun don't shine/wind doesn't blow, and you'll be good to go.
Get an automatic transfer switch at the appliance level. Let's say you've got a window air conditioner unit. Get an $85 120v/30A transfer switch (http://www.pplmotorhomes.com/parts/rv-power-cords/automatic-transfer-switch.htm) hooked up to your solar-charged UPS and regular house voltage.
When the UPS dies, the ATS will switch to regular house power.
I've been on slashdot so long I'm starting to get out of touch with the cool stuff if it ain't on slashdot.
In order to protect workers, you really do need to use high grade gear if you connect your generator to the grid (I don't know whether $2K is a reasonable price). But, if you want to just power some circuits in the house, get a transfer switch and connect the circuits to it. You will then be able to switch the circuits from being powered by the grid to being powered by what you generate.
A lot of ham radio operators set up separate 12vdc systems for powering radios and other emergency equipment. 12v deep cycle batteries plus ways of charging them -- solar panels and a solar charge controller, ac chargers, and a handful of diodes and maybe some relays so the ac operated charger only runs when needed (and there's no solar power available). Such systems are fairly simple and robust.
Use your homebrew power generating equipment to charge a bank of marine (deep-cycle) batteries. Then run the output from these through an inverter (large one) to power your AC equipment (optionally use the DC directly when possible. You then also use the grid to charge the batteries.The grid cuts off and there is no backfeeding to the grid.
There is a fair amount of info on this type of thing, as many people in remote locations live like this, with no grid power at all. They just run a generator every so often to charge their batteries.
This type of thing can be DYI'ed on the cheap fairly easily.
Note that you will be loosing some energy (mainly as heat) when running exclusively off the grid power. Converting the power from AC to DC and back isn't free. But if you have enough current coming in from your alternative source it may be worth it.
Also look in to peak and offpeak pricing from your power company. Some offer this even to residences. This would allow you to run the charger only during offpeak hours and pay a lower rate per kilowatt hour.
Would this pass your local electrical codes? Who knows...
Instead of doing your whole house, maybe you should do something a bit different: limit it to one or two circuits and put those on the homebrew solution (Easiest and best solution: Your lighting for multiple rooms). You can use a single relay (double pole) to control the source. When you have enough solar/wind power to power these units, the relay switches the load to your system. When you run low on juice, it switches to the main system. This also protects people on the mains because you cannot put power on the grid. (You probably won't generate enough power to do that anyways, especially on a budget).
Converting part of the house to DC has already been mentioned.
Another option is to split your house wiring. Put some circuits on your home generator and some on the grid.
Of course, with solar or wind you run into the problem if downtime.
If you put a switch between the two that makes sure the two never feed the same circuit within a few seconds of each other, and you only plug in devices that can tolerate several seconds of down-time, then you should be in decent shape. If the elements on the circuit are purely resistive then a fraction of a second of downtime is all you need.
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Nope. Go to -48VDC - just like the phone company.
(Still looking for copies of the old bellcore engineering documents on the 48VDC systems.)
There is one other option that would meet all insurance regulations. Buy a large UPS device, some of these can be charged by either 120v mains or low voltage (solar). Then pick the few small appliances or maybe 1 large appliance that you want to run off mostly renewable energy. No exactly a "grid tie in" but it would give you the benifit of using solar to charge the battery when available, and charge off 120v mains when it's not - and as long as the device is approved - you'd be fine. UPS boxes are smart enough not to send power back to the lines.
You could move a circuit or two off of the grid breaker box to their own solar/wind powered circuit(s). /no wind use? That does change the options available for the inverter selection /components as they have to manage multiple inputs, charging, etc.
Simply install a small second breaker / fuse box and move a couple of wires. Might want to have an electrician do the work or inspect it to make sure you've covered everything. Do you want to have battery backup for night time
Once your hobby has progressed to the point of wanting more of the house on the other solar wind then you can think about the grid inter-tie inverter.
The higher end inverters also tend have a cleaner A/C output, that is its closer to a sine wave than the lower end ones, at least that used to be the case. It isn't much of a deal for most things but some electronics are picky about the shape of the input wave.
Just some things to think about.
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Run these on their own completely separate circuit; you can use regular 12 volt batteries as your energy storage and charge the batteries with solar cells or a automotive alternator driven by some kind of alternate energy (steam? water wheel? windmill?) or any combination thereof. If you have multiple generators be sure to electronically isolate their outputs; big diodes are the usual solution.
If no alternate energy is available and you need lights then a common battery charger will take care of your needs. If your house was wired to "standard" then your overhead lighting is probably already on a separate circuit of its own; this makes it even easier.
There you go; by using commonly available items and starting small you can start generating your own power on a budget. A few hundred watts of lights goes a long way...
I would suggest breaking down what you want to divert to solar and what you don't, in other words do you just want to power the fridge or air conditioner on solar, then rewiring for it. I've only setup a solar generator to supply power to a UPS, in case of blackouts, I can recharge most items.
I would also think long and hard about criminal liability for the death or injury to utility workers who get killed because his system was backfeeding the power grid.
Those transformers on the poles work just as well when operated backwards, stepping the 120V output from your inverter up to the 7-13 kV distribution level. Unless your inverter has enough "smarts" to isolate itself from the grid in the absence of utility power, your system will attempt to power up your part of the utility network, resulting in a severely overloaded inverter (with resultant blown fuses/smoke/fire) at the best, or a serious hazard to lineworkers at the worst.
People HAVE been sued when lineworkers are killed/injured by improperly installed generators or PV systems that resulted in backfeed. Prosecution for criminally negligent homicide is also a possibility, especially if the prosecution can prove that you KNEW of the need for automatic isolation, but failed to provide it in order to save a buck.
In short, use properly designed equipment, installed according to manufacturer's instructions (and get the proper permits/inspections as required), or stick with a completely isolated low voltage DC system.
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If you have a pool, there are systems you can buy that run your pool pump off of photovoltaics. Pool pumps are infamous energy hogs, and you can run a pump off of DC, which cuts out the inverter. Getting rid of the inverter improves efficiency and cuts the cost of the project. This is not a grid-tied system.
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Conventional sources have had decades of government subsidies. For example AFAIK, there isn't a single commercial nuke plant out there (US) that has all private insurance, the government insures them for big failure, plus the government picked up the billions of dollars (in 1950s and 60s money) tab to even develop the things in the first place. Centralized magecorpos grid electricity relies on land seizures with no compensation to the owners for powerlines. buncha stuff. Back in ye olden days (1920s) they *forced* people to give up their early model windchargers (there was a really robust market then too) if they wanted to add into the grid. Basically killed that market off on purpose to prop up the fatcats who wanted to send you a bill every month forever. Anyway, here's an overview site: http://www.taxpayer.net/energy/oil-gas.htm
So, as a corollary, if conventional sources were really cheap, they wouldn't have needed subsidies, and decentralized "green" power would have done much better (rent, or build equity and own, two choices there)
The problem with enthusiast wind generation is that power scales exponentially with the size of the turbine blades. Hence the attractiveness of offshore windfarms, as honking great beast turbines don't spoil people's view.
Everything I needed to know about life, I learnt from Blake's Seven
Err...not necessarily a good idea. If you lower the voltage your current requirements increase for the same power load. This increases the heating in the cables and thus increases the chance of an electrical fire.
I'm sure that you can do it safely but you will need far thicker cables than a 240V system and be careful that you have good connections. Plus you will loose 10-20 times more in power transmission than before.
When I was going through CERT training, I was amazed at some of the precautions that folks from DTE (Detroit's electrical company) and the fire departments have to take. I was also amazed at the number of people - pole workers and firemen - who have died on the job because people run generators and don't have backfeed handling. Forget your house being worth 2000 bucks; think about the people on the line. Also, just to put it in a capitalist perspective, when the lineworks got to a downed neighborhood, they would first try to listen for the buzz of a generator. If they heard one and they couldn't get the owner to shut it off, they would try and surge the line locally into the house and blow the generator/fuses. Apparently, it often worked and they've never been successfully sued.
Sounds like you need to be looking at storage options, not grid-tie.
Yo dawg, I heard you like the Ackermann function, so OH GOD OH GOD OH GOD
I am not sure if it will be useful, but here is an article on something similar : http://www.mdpub.com/Wind_Turbine/index.html
Energy conservation is the most cost effective/easiest way to reduce net power consumption. Electric Generation facilities tend to become cheaper per watt as the generation system gets larger.
Without a doubt, you should use safe practices, but a homeowner/lessee have a lot of latitude. While UL equipment is the norm, there are many safe home-brew systems that can save money depending vastly on what you do with them.
The conventional wisdom of pubs like HomePowerNews and The Mother Earth News seem to advocate understanding battery technology and inverters, and also where you're consuming juice where those consuming devices can be better used (unplugged when not in use) or replaced with more cost-effective devices.
Low-voltage devices might be able to be used but may be actually more expensive to both buy and power over the long term with a shorter usage life.
Driving the power company's meter backwards may or may not even be legal in some states/areas, so you need to consider running dual systems (not as tough as it sounds) to get genuine savings over the investment life of what you do.
Solar may not work in some regions or areas; windmills may be restricted, and other generating schemes may have additional implications. Every site is different and needs to be treated that way. That said, the more we can save initially (and rationally) the better. Generating your own juice needs some thought because there's a varying amount of wisdom about what works in different applications. But by all means, DO IT. Permits aren't often required, but it's municipally defined, or thru state laws, or by the National Electrical Code and whatever your insurance company agrees with.
---- Teach Peace. It's Cheaper Than War.
I would also think long and hard about criminal liability for the death or injury to utility workers who get killed because his system was backfeeding the power grid.
In an era where the power grid is considered a terrorist target and government is in an overreacting mood I suspect there may be serious criminal liability even if no one is hurt.
Did anyone else initially misread the headline?
We're currently examining replacing a lot of lights on a boat with LEDs, because they make the battery last a lot longer before we need to kick in the generator (it's also safer because the mooring lights don't burn out). Maybe we'll add solar panels, but that's phase II.
:-).
Your average lightbulb converts (AFAIK) about 65% of the energy into heat - which we don't need as the boat already in a hot climate
Insert
The whole electricity thing is overrated. Making solar hot water is much less dangerous and cheaper (and you get to use a blow torch). Look at the roofs in your neighborhood, there are sure to be some unused/abandoned hot water panels that you can pick up cheap or for free.
Only use electricity for what makes sense. For heating water, think about concentrated solar or methane. This focus on the grid overemphasizes unreasonable centralization of alternative energy that can be made on the homestead and power the needs of a family.
I bought a 60 watt kit from Costco.com, which I have charging a deep cycle battery that powers my 12-volt outdoor landscaping lights at night. The lights are much brighter than the typical solar lights, but still completely solar powered. I also have a 3kw grid-tie system, but no battery storage on it.
Off the top of my head, a $100 fan center could shut the power connection when the feed from the power company goes down. Attach a 24V AC transformer to the power company line and wire it to the fan center's controller. Power goes down, circuit opens.
I can probably fabricate a circuit with an oscillator that syncs up to the 60Hz of power. After that, it's a matter of how to convert from DC to AC. It doesn't seem hard to me.
Best regards.
An AC has already asked, but I'll chime in too.
Details! I'd love to hear more about how you did this, and I'm sure that many others on here would equally appreciate any hints/information/etc you can offer.
You can't attach a 'home-brew hack' for putting electricity back into to the power grid. It must be taken into consideration that your house would have to survive an inspection and nobody at the power company is willing to risk death because you were too cheap to provide a tested or approved solution.
Also, if you are going to waste bandwidth on the Internet, why not give some damn details about your plan? Make it interesting at least. Right now, your ramblings seem to indicate you want free help for a possibly commercial idea you want to keep secret.
first - buy the damn $2000 box. It's worth it in sleeping soundly.
Second, I find this fascinating that instead of storing energy to use later, we instead use the power of the utility company as a market maker to sell energy when we have it and buy it when we don't.
Surely smart slashdotters can come up with some other way of converting energy to value that can be traded. For example, can excess solar power be used to sequester carbon or synthesise gasoline or do some other valuable work that could be later redeemed for cash or credit to offset the utility bills - can I earn a carbon credit and sell it to the utility company ?
Nullius in verba
These guys: http://www.wiebetech.com/products/HotPlug.php have a UPS system that syncs itself to a live power line (or so it seems). It might be worth contacting them to see if it can work for this.
Here's what I did with my 200Watt Panel. I charged a 30Amp 12volt Battery. the panel was connected to a solar charger regulator. I designed a circuit years ago that will power an invertor from both the panels and the battery. This worked well. I used it to power my computers, back then this was a node on Fidonet. Internet connectivity was not even available for modem dialup then. I bought the panel used for $100.00. The panel lasted until I bought my house. bummer. My newphews were throwing a baseball around and the ball hit the panel. You do not need to connect to a grid.
I was actually thinking about building a hybrid model. Using a combination of solar and grid power. Eventually building up enough solar capacity to get off the grid.
Also buying used surplus panels can be a good deal sometimes. That's how I got a $500.00 panel for $100.00. the 200watt panel was putting out 190watts at full sun when I got it.
Good point, but also consider the Return on Investment. If you do go ahead and drop the 2000 bucks - you can sell energy back to the power company (assuming you live in one of the states which permits this) usually during peak hours too. Whereas if you skip this step, you cannot sell your power back to the grid.
Prediction: The real iPhone killer is going to be sex robots from Japan. Think about it.
If you keep the UPS plugged in AND on a solar panel to charge, won't it feed back to the grid if it loses AC coming in?
Current solar voltaic tech _will not_ save you money, it will likely be considerably more expensive than just paying for the power.
However, if you want to do some solar stuff for a hobby (which I have done) and cost isn't the primary concern, then don't even tie to the grid; if you have to ask the questions you ask, you aren't even remotely qualified to homebrew a grid-tied inverter!
For a hobby project, consider 12 volt stuff - perhaps use solar to run your computer (you will need to build a computer PSU that runs off 12v and provides the right voltages for your motherboard - this can be a good, informative learning electronics project). If you have a garden, you could use a 12v solar power system to run things like garden lighting and your pond pump. Or perhaps you can run a couple of appliances, isolated from the mains electricity, off a non-grid tied inverter.
However, there are some things to note about solar. A panel only makes rated power in *full* sunshine, with the sun exactly perpendicular to the panel. If the panel is fixed, and optimised for the mid day sun, you won't even make half rated power more than two hours either side of mid day. A thin layer of cirrus cloud will cut power output to about 1/2 to 1/3rd of rated power. Even just normal summer haze will have a significant impact. On a bright overcast day, where faint shadows are still cast, you probably won't even make 15% of rated power.
If this isn't strictly a hobby project for the fun of it...
If your motive is to be green, note that if you have a typical commuting distance, you can probably save more money by cycling to work just once a week instead of driving that day.
If your motive is to save money, then you'd do MUCH better with a solar hot water heater - they are so effective that people make significant savings even as far north as I live.
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Having a renewable energy system backfeed the grid under normal circumstances is perfectly fine (and lots of fun to see your electric meter spin backwards). It took a lot of effort by system manufacturers and RE hobbyists to get utilities to reluctantly accept so-called "net metering", and allow small producers to sell power back to the utility. But there are very specific requirtements for doing so, including automatic isolation of inverters and a visible, accessible disconnect switch on your house so that you can be physically disconnected is required.
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I don't see any reason you couldn't plug solar into there instead of a generator. I had never thought of trying that. I suppose that since I planned it for emergencies, I generally wouldn't expect the sun to be shining then (rain/snow/ice storms), but I like the idea.
The panel typically costs $200-$600 and the electrician to install it another $200-$600.
Edward Burr
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talk a lot more than the people who get it done.
http://www.otherpower.com/otherpower_systems.html is one page on a site run by a group who develop off-grid and grid-tied systems they might be a fun place to browse, also try their discussion page. Some of the stuff they get working looks like props from a mad max movie but they do work. wood fired steam engine driving a dynamo, anyone?
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One of my personal dream projects is to run Power over Ethernet or some other DC-based power grid in the house. There are tons of AC-DC converters in most houses (computers, cell phone chargers, etc.), and it'd be a lot more efficient if we could run just one AC-DC converter with DC-DC converts on the specific devices as needed.
This should go hand in hand with any home generator, since most such projects use large lead-acid batteries to store excess power, so you won't need an inverter at all for most applications.
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So do it off the grid. Make a 12 volt circuit and buy some car appliances for your house or get a large scale inverter like a 1600 watter for like $150 and power some real appliances seperate from your home's connection to the power grid. You could run a small air conditioning unit in just your computer room hooked up to a large solar panel outside with a car battery or massive capacitor or something and it would only run when there was enough energy. That way it could cool off your hottest room and effectively make you take less energy from the grid to cool your house. And it would be crazy cheap to set up a couple 12 volt, 50-100 watt halogens or better yet, low wattage LED lights in just one room on a car battery/solar panel setup and have free light all day basically. And none of that would require sending anything back to the grid so no special equipment :)
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Just a thought but, If you have a detached garage you could play around with just getting the garage off the grid.
Really, don't. If you have an electric hot dog cooker that you want to run off solar power, great. Hack something together, have a blast, cook a hot dog. Heck, grind your own mustard.
DO NOT try to feed power back into the grid on your own. The power company will hate you, the insurance companies will hate you, and even your neighbors might hate you. First, consider the local building codes: are you a licensed electrician, insured and bonded by the state? If not, you're breaking the law, and the insurance company will NOT pay for ANYTHING that happens to your house. Even if it burns in a brush fire.
Second: consider catastrophic failure. It can happen - the odds are low, but the grid is supposed to be resilient against such things (even if it largely isn't now, thanks to deregulation). If you blow up your local pole pig (step down transformer), you'll have to pay for it, and your neighborhood won't be happy. They are also full of quite nasty dielectric oil - you don't want that on your lawn. Even simply screwing with the phase will quite likely have the electric company breathing down your neck.
Put it this way: you are an ISP, and one of your customers builds a ramshackle NAT box for home use, gets the interfaces wrong, and accidentally starts issuing IPs to other customers. What do you do? You cut him off quick, and follow up with a nasty phone call. Why would the electric company treat you any differently?
Is a solar hot water heater.
All you basically need is a solar water heater array, some tubes, a pump and a secondary water tank.
The sun pre-heats your water, stores it in a water tank that feeds your main water tank.
You'll save on your energy bills whether your water heater works on gas or electricity, and it'll pay for itself quicker than any other renewable energy rig out there.
It even works in cold weather if you get a properly insulated solar box.
Wouldn't an old UPS have circuits similar to what the OP was looking for. They sense when the grid goes down (and supply power) it seems like a starting point anyway. You could Use your self generated power to run your computer.
Another Homebrew project would be growing Algea to get the oil out of it. You could then turn it into biodiesel and burn it in your oil furnace / mix it 10% with gas and use it in your car / run anything diesel you may have.
All generalizations are false, including this one. Mark Twain
The only posters modded up are snarky jokers or negative nay-sayers, but I say GO TO IT MAN! Just ignore the grid, because there's no way around the expensive safety stuff. Power your equipment from batteries - it's not very expensive, and not as limiting as you'd think. You're not going to run your heating system on it, but you can easily chip away at small things, like external lights or things used infrequently like kitchen appliances. For example, this guy has step-by-step instructions for a hobbyist-size windmill charging batteries. His entire rig was about 150 bucks. If you skimp and buy some stuff that he made from scratch, you're still looking at a few hundred bucks tops. http://www.mdpub.com/Wind_Turbine/index.html
Far better to have a bank of batteries, a charge controller and an inverter and run that into a totally separate circuit with separate plugs into which you are plugging known items. With this you don't have to worry about grid-tie, and you can zone your home into ongrid-offgrid sections, then as you grow your system you can reduce your ongrid circuit. Solar is by far the least maintenance intensive option so is a good starting point. Wind would be the next step - you want at least two inputs. As to inverter - you can't beat Xantrex.
First and foremost, tho - reduce your use. Develop new habits, replace old appliances, adopt new methods (line dry rather than clothes drier), convert lighting over to CFL's, get a laptop and turn power-hungry PC off (unless gaming), put media center on a wall-switch so you can really turn them off (they stay on and draw up to 40% of on-power while "off"), replace or clean out water-heater, consider solar-water heating, plant shade trees that'll shade the house, yet lose leaves and allow warming sun in the winter, consider a hot-wall where air is heated from the sun then piped back into home, etc, etc. These actions alone will reduce your bill significantly. Generating, storing and using wattage is very expensive per watt - cut it down and your system will become much cheaper to build.
Have fun. You may spend a bit of money getting this thing together, but you'll reap a lot of satisfaction on independence from the gouging utility companies. I value that over any nickel and dime saved.
Xantrex has everything you need for the indoor part of your project, whether grid-tied (called "net metering" in Canada) or battery-based.
Add to this the synchronization capability. I'm not sure about inverters, but if generators are ties in out of phase you can kiss your generator goodbye in a spectacular way. I can't imagine inverters like it any more.
"As God is my witness, I thought turkeys could fly." A. Carlson
I'm curious about this, because I've paper-designed some similar things -- trying to use car alternators as generators by driving the field coil with AC from the grid, so the output is automatically synchronized with the grid. The problem is that since you're feeding power back into the grid, how do you detect that the grid's down? coz it won't be if you're feeding power back into it. Likewise, you seem to be doing the same sort of thing: how is your fan controller going to know whether the electricity it sees is from the local coal plant or from your little cogeneration setup? If your setup works, I'd love to know how and why, because I'd love to build something like this. I just can't figure out how to get it to work without resorting to ugly, dangerous things.
Nostalgia's not what it used to be.
"a search for a solution in search of a problem."
I too am a little baffled. There's a lot of off-the-shelf 12v stuff on the market, up to and including 120v AC power inverters and those grid tie-in units. I'd start with a solar/wind driven 12v system with halogen lights, the lights are at all the hardware stores and you can really step out of the stone age with proper illumination.
The cost of that cleanup, of course, will be borne by taxpayers, not industry.
I have been giving this some thought as well. Since tying to the grid is difficult why not remove some household appliances off the grid. Why not build a generator that runs most of the lights in the house, or a solar powered attic fan... My thought is if I can provide for my routine electrical needs and let the power company provide for the big
loads it might be more economical.
Good luck.
Inform them of your situation.
Perhaps they have a smaller unit that just isn't in stock at the store and tell you where they can be found or perhaps they know a competitor that has what you need.
Check in old issues of Home Power Magazine. There were articles where people were setting up grid tie solar setups on a small scale safely without some of the expensive utility work. The articles were titled Gorilla Solar.
I think the most effective "hobbyist" renewable energy use is to preheat water for your hot water tank. Either passively with a tube system or actively with solar panels. Heating water is one of the highest energy costs consumers have, generally speaking, and it's a very easy solution to your problem. No grid tie-ion necessary and the biggest bang for your buck, typically speaking.
Combine that with grey water heat exchangers and you'll be saving a lot of energy on heating water.
For more green options, put some rain barrels out and only use house water for things you do in the house. Use the rain barrels for your lawn/garden needs. Compost is your friend too, if you do any lawn and garden work.
"Growing old is inevitable; growing up is optional."
Induction motors can be used as generators and they automatically shut down when grid is down. Induction motor will continue to make electricity as long as it's rotor keeps on turning because of the remnant magnetic field in rotor. Even if the rotor stops turning, some magnetic filed might still be present in rotor, depending on magnetic alloy type, and will produce some voltage if the rotor starts turning again.
Also if not properly protected, it might overload if grid power is turned off. For grid tied generators an controller is needed to prevent connecting the AC induction motor when for example, wind speed is to low because in that case the generator will work as an fan, effectively eating the power form the grid. Controller must provide soft or at least partially synchronised connection to the grid.
Oh shit I forgot about LEDs. Way more efficient, not really commodity packaged for end-users yet. This is where the "hobbyist" bit comes in.
The cost of that cleanup, of course, will be borne by taxpayers, not industry.
Do what I do. Salvage 12Vdc batteries every fall from auto shop replacements, recondition them. (getting H2SO4 is problematic) Charge this bank with 1 or more surplus solar panels with a diode.
Run some lights, computers, audio, experiments etc from nice clean predictable direct current.
Plug in a deep cycle charger for backing up variable solar input and usage.
Accept plumbers and electricians advice on safety but not always on engineering.
Forget about heating and freezing (electricaly)
Finally, check out these guys.
http://groups.yahoo.com/group/12VDC_Power
yours douglas
We know exactly where one cow with Mad-cow-disease is located among
millions and millions of cows in America.
So, be afraid underling.
I'm guessing that you can just buy a couple relays for under $20 and do the same thing that the $100 fan center would.
Of course, you would have to worry about the home power source accidentally supplying voltage to the transformer and keeping the relays closed. It would probably be better to throw some electronics on the mains so that it would detect voltage fluctuations instead. It's no good running 400V from the power company through your home brew power source during a surge, either. One solution might be to take the guts out of a UPS and use it's electronic switching system, but just replace its relays with some rated for the amperage you'll be playing with.
"Grid tie" is expensive or at least has a $2,000 minimum cost. But there has always been the option of going completely off-grid. Houses in the dessert thate don't use utility power clearly don't need a grid tie inverter. OK you can't go off-grid?
But as a hoby project maybe you can take just one light bulb off grid. What you do is make one of your lights, maybe an outdoor portch light completely independent of utilty power. You don't even need an iverters if you use a 12 volt bulb. You run the bulb off a battery and charge the battery with a solar cell or wind generator. Many people who live on sailboats live off wind and solor power because you can't get a cord to reach across an ocean. I pplace that caters to sailboat owners will sell you everything you need.
he core of the system is the battery. Size it in "amp hours" so that the battery can storefour times as many amp hours as you plan to use and buy solar pannels rated for double your expected use. You portch light will need a few hundred dolars of equipment to make it run. and you will save abut 50 cents a month. The payback will come in a couple centuries or faster if the cost of power goes up. But it is a hoby and you just want to learn. To actually save money you need to work on a scale larger then just one light bulb. Take more of the house "off grid".
The key here is that your system not be in any way connected to anything that is on utility power. You are building a completely independent system.
Grid tie is attractive because an independent system needs a battery bank and that bank is the most expensive part of the system as the batteries have only a typical five year life. With grid tie you can loose the battery racks.
homepower.com - technical details
backwoodshome.com - how people did it cheaply at home ( you will have to search for the info )
Wander into the bookstore and find the magazines?
Home Power Magazine
Backwoods Home Magazine
Back Home Magazine
Countryside Magazine.
And no, you dont need to tie into the grid with your system if you are just trying it out.
Use the solar , wind or whatever to power something completly seperated electrically from the grid. A shed a set of yard lights or whatever.
The bigger impact is looking at your energy usage and cutting your load. CF lights instead of incandescent. Unplugging electonics when not in use.
Isulation and sealing the house so it uses less energy.
The problem of generation needs to be broken up as follows: 1. The conversion to AC should be sinusoidal. Simple square wave inverters will not work. 2. To have a sinusoidal output, PWM needs to be used 3. The PWM control circuit needs to be mains synched PWM - Pulse width modulation - a way to generate non square wave outputs from efficient switching circuits. This is not the only problem. I know that the solar cells that can generate even 5% of the total electrical power that we cosume on an average are pretty darn expensive. Vossman have you got it at scrap rates? Well even if you have not everyone can. Additionally there will be a costs related to batteries, mounting, wiring etc. So what's the point? Unless the government heavily subsidizes it.
I have 4 m2 PV cells (in the Netherlands) and on sunny days have very low resulting power draw from the grid.
I also have 4 m2 solar water heating, and use absolutely zero gas from jun-sep and very little in the surrounding months.
Payback time for solar water heating is less than 7 years, and for solar PV it is 20+ years in the Netherlands. Raising oil prices makes it more interesting.
Not really energy-saving, but ecological too: If you are in an area where it rains a lot, you can also divert some of your roofs to a water container (mine is 10 m3) and use that water for flushing the toilets, doing the laundry, and watering your garden. I have that since 1994 and it works great.
Solar water heaters are something that can have a dramatic payoff and they cost much less than photovoltaics. You need to know what you're doing to prevent pipes from freezing and to avoid leaks, but that just requires knowledge and skill rather than lots of cash.
I've seen projects on the web as simple as coils of pipe laid in a glassed over, insulated pool of water (the water provides thermal mass). The heat reservoir pre-heats well water before it reaches your water heater inside and reduces energy use. There are also much fancier systems with mounted panels.
You can also upgrade insulation or install more efficient windows. Conservation isn't as sexy as putting up solar panels, but it probably offers a quicker return on your investment.
Good luck with your projects.
For wind power, using an induction motor as a generator is one option to consider. When the motor is driven past synchronous RPM, it begins feeding power back on to the grid.
It is inherently synchronized with the grid. However, you will likely need to provide some sort of anti-islanding protection. UL listed components for most of the set up is readily available, which helps when trying to get the OK from your local utility.
In a blackout, you can disconnect from the grid and energize the field with a battery powered inverter, provided you've still got wind.
A properly driven five horse induction motor can generate enough power for most residences, and they are available for $100-200, typically. A good scrounger can get them at scrap price or less.
The post on Home Power is spot on. A low cost inverter commonly used is the Sunny Boy line. They are still not "cheap" but you can get one for around $1,000 if you shop around. You also might be able to find a used or refurbed one for even less. As many others have said, an even cheaper way is to get a deep cycle 12 volt battery, a charge controller (can be home brewed - look once again @ Home Power) and an inexpensive non-grid-tied inverter to power specific loads sized for your setup. You can then build upon this and move other loads over time as you grow your system. Good luck, and as they say at HP, keep the spark!
sig, what sig, am I supposed to have a sig? I don't want a sig. I don't need a sig.
I can probably fabricate a circuit with an oscillator that syncs up to the 60Hz of power. After that, it's a matter of how to convert from DC to AC. It doesn't seem hard to me. Your kung fu is better than my kung fu.
If you do fabricate this interesting little setup of which you speak, please document your efforts and publish it on this web, on instructables or something. Open-sourced, near-free energy reduction projects is something this world needs.
You can't take the sky from me...
...this hobby setup only cost a few bills: http://tuzen.blogspot.com/2008/03/practical-solar.html
AIMS POWER 3-WAY AUTOMATIC TRANSFER SWITCH
less than $200. There is at least one on ebay right now.
type error at quotes. it should be:
Induction motors can be used as generators and they automatically shut down when grid is down.
You can't take the sky from me...
Two questions:
1) What is a "fan center"? Google gives an NBA web site as it's top result.
2) As already pointed out above, if you are putting power out on to the grid wouldn't the "fan center" be getting it's power from you when the grid is down?
I think the easiest thing a hobbyist can do is store his power for personal use. Charge batteries during the day and use them to power your (DC powered) lights at night. At some point you save enough on grid charges to pay for the equipment.
Making solar, wind, or hydro power a profit center is a bit more ambitious.
But for a small scale system, the ability to tie in to the grid is essentially useless. Since you're not going to be generating enough energy to sell a significant portion back to the electric co, why not just have separate circuits to power small items like alarm clocks, charging electric toothbrushes, etc....
Unless you're going to be generating significantly more energy than you use, I don't see the grid tie-in as being all that useful.
And once you do produce that amount, you're not really in the hobbyist league anymore, which is what the original question was about.
While I agree with your "safety first" attitude in principle, I'm really glad mankind as a whole isn't so conservative, or we'd still be in the 10th century. Live a little! Edison blew himself up hundreds of times and still kept hacking.
"Eagles may soar, but weasels dont get sucked into jet engines."
I am unsure how an alternator would sync phase, but I don't know that much about car altenators. But if I wanted to hook an inverter to the mains I would use a simple system: for my inverter pulse the DC through some power transistors using a capacitor afterwards to smooth things out. As far as syncing: the oscillator controlling my inverter would be ran off a phase-locked loop. (http://en.wikipedia.org/wiki/Phase_locked_loop) Continuously syncing phase with whats on the mains. For islanding mode operation (shutting power off to the line when the line goes down. I have though about this for a long while. (I like thinking)If the line goes down its either because of a short or an open. A downed line or one shut off for maintenance Your inverter has to respond within 60ish ms to be legal to use as grid-tie IIRC. If there is a short your out flowing current is going to shoot way up and max out your inverter. If its an open the current will drop way down, not always to zero. So if you monitor the outgoing current and if there is a big change from the average current have it shut off outgoing power to the grid. This would take some trial-and error and research, however. FYI, I am not an EE, but I am a CET!
sig?
My clothes drier died a few years ago, replaced with rope between trees, the cost of 230V/50A for an hour, the rope paid for itself in under a month and is "completely off" grid... Not geeky, but works...
I wish I was clever!
You could probably make batches of bio-diesel and buy a diesel generator.
http://www.northerntool.com/webapp/wcs/stores/servlet/product_6970_200337757_200337757?cm_ven=Aggregates&cm_cat=Google&cm_pla=Generators%2C%20Portable%20Generators&cm_ite=168100&ci_src=14110944&ci_sku=168100
Rated at 5000 watts ~~ 50amp peak, that should run your house.
The question is if the $1~$2 biodiesel running a generator is cheaper than buying electricity. Remember, also, you can feed back into the grid and reduce your electric bill.
If you have a diesel car, that works too.
I looked in to solar panels for our house recently and came to the simple solution that it takes practically forever to recoup your costs. If you want to use solar energy just for the sake of it (maybe you're green, but I'm not), you're going to have to pay for it. If you're looking to save money, look elsewhere.
Whale
How many city electric workers are going to agree to touch your electricity when they see some homebrew box rigged up to your breaker? I'm guessing that whatever you attach to your city's power grid has to be approved and licensed, and has to meet local electric code requirements. That probably kills most homebrew solutions.
Engineering Technologists = Engineers who don't think sociology or psychology is important to understanding how charge moves.
It's been a long time.
You say in one breath you want to do the hobbiest Solar/wind power generation and in the next breath you jump into Intertie syncing inverters.
That's like a guy wanting to go fishing part time going out and buying the Queen Mary.
If you want to "hobby" or get into solar at home then start here.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=90599
This kit coupled with the right battery is an AWESOME start. I added power to my Shed with it for lighting and it works fantastic. so well I bought 2 more for the garage and it give me ALL the light I need in both. That is a great way to get started in it. not by going to the top of the line full boat alternative power I'm gonna intertie to the main power system stage.
I used to be very solar at my last home. I had a huge Dome that had over 6500 watts of solar and I inter-tied to eliminate the battery cost and maintenance, I hated dealing with the batteries weekly. Honestly the inter-tie lost me money in the power I generated because the locality refused to install a reversible meter. you do not NEED to do it that way, you can get an inverter and tie in specific circuits to their own system.
Do not look at laser with remaining good eye.
I dont think a UPS is going to have relays, it would probably use some sort of thyristor. (Solid state devices that can act like relays)
Simple over voltage protection would come in the form of a zener diode in parallel across the power rails. Or, perhaps an antifuse.
sig?
It's a bit oldschool, but maybe a better idea would be to drive a DC brushless motor with the voltage from the solar panels et. al., attached to a variable size pulley, which would be attached to an AC motor attached to the grid. Control the pulley size based on the phase shift between the induced voltage and the line voltage, and you've got yourself a ghetto method for relatively high quality conversion of DC power to mains power.
It's been a long time.
Depending on where you live, many utilities will subsidize the cost of renewable power installations (usually solar PV). That should help you defray the cost ... although you'll probably have to go the professional route.
... I don't recommend a hobbyist screw about with hooking stuff up to the power grid. I know one gentleman who did it, but he's an expert in power generation systems at a major E&C firm. (He built small biofuels plants at his house in the country.) If you don't have a professional level of expertise, please don't go messing with the grid.
Alternatively, you can take advantage of a power purchase agreement: the manufacturer sells the hardware to the power company, which hooks it to the grid, and you pay for the kWh you use. The PPA model was written up in the New York Times back on March 28.
As for a homebrew solution
In a lot of the US, there is no provision for reverse metering. Its on a state by state basis and not that common.
why not just have separate circuits to power small items like alarm clocks, charging electric toothbrushes, etc....
Are there really people investing in new sources of energy so they can power a toothbrush? Remember the mantra is reduce, reuse, recycle...
Ditch the electric toothbrush and can opener, the constantly charging rechargable tools you use infrequently, the wall warts that are always buzzing, and maybe it won't take as many solar panels you keep your household running.
But for a small scale system, the ability to tie in to the grid is essentially useless.
I don't think the primary goal is to sell your excess production back to the grid. I think the goal is to not have to put a new seperate set of cicuits. What are you going to do on a cloudy day when the solar panels aren't putting out as much juice, or on a windy day when the windmill kicks in to overdrive? Run around switching plugs from one outlet to the other?
I would just try to run a single device off my solar/wind generator. I would do this by plugging the device into a UPS, and then plugging the ups into a little custom built automatic switch box that would normally be drawing power from an inverter connected to the solar/wind power. When the switch box detected the inverter voltage drop below a certain limit, it would switch to grid power. You could increase the efficiency by somehow charging the UPS battery directly from the solar/wind 12v instead of inverting and then dropping back to 12v. Essentially you would be using the UPS inverter only. I have never tested this but if I only had a few hundred watts of solar/wind i would think this would be much more simple than fully grid-integrated. Plus the battery saves you when the switch is switching.
http://www.google.org/recharge/
Choose a small subset of your usage, like a laptop and maybe some other electronics. The usage should be small load and steady or big load and rare to keep capacity and cost low. Charge the battery from the solar panels and then use an auto adapter or inverter to run the laptop. The auto adapter is more efficient. 12 volt LED lights are also a good solar application.
If there is a long period without sun you can always grab a battery charger to charge the battery til the sun returns.
Minimum system would be battery ($70 at WalMart), 40 watts of solar panels ($200 at Harbor Freight) and a charge controller for another 50-100.
If your laptop is very efficient then every hour of sun charging might give you 1/2 hour of laptop and if you exceed that usage level for very long the battery goes down.
I wanna see the electric company's meter run so fast backwards that it causes the earth to tilt it's axis!
Tsukasa: All I really want, is to be left alone...
I'm in the western suburbs of Chicago, and I pay 7 cents/kwH for nuclear power from ComEd. I specifically switch to time of day metering because I ordered a Tesla Roadster. Charging it at night between midnight and 4am gets me power for 2 cents/kwH. If I really wanted to, I could install a Xantrax inverter that charged lead acid batteries from midnight to 4am, and than feed the house during the rest of the day from batteries, but it just isn't that practical once you price out the equipment. On the other hand, the Roadster does use a fair amount of power to charge (70amp/220V draw on a 90amp/220V circuit), so it does make sense to time of day charge that bad boy.
No, not the parcel service.
What's stopping you from "tweaking" an "Uninterruptable power Supply" so the batteries can also be charged from your solar panel/windmill/water wheel? When the grid is up it can top-up the charge; when it's down the UPS kicks in, as it's designed to do. At the output end you don't need to know where the batteries are getting their charge from, you just watch your TV/surf the web/run your energy-saving light bulbs.
As long as you don't plan to sell your excess back to the grid I don't see a problem.
An article a few days ago described homebrew ethanol. I'm not sure it is as efficient or high-quality as factory ethanol. Also sugar price is highly subsidized in US. A run on sugar might turn out the like current rice shortage.
I have an engineering degree(That is, I has enginer degre). I took 20 credit hours of humanities, none of which were sociology or psychology(2 economics classes, just enough to be dangerous, 2 philosophy classes, which is also just enough to be dangerous, and an early American history class that was way more forgettable that the book "1776"). If the school is pushing more than that, it probably isn't a good school.
Nerd rage is the funniest rage.
It's very true. It's been a hard battle to allow net metering. The only thing I wanted to add was that you must have a lockable, utility-accessible physical disconnect on the exterior of the building. This is so a line worker/utility worker can be assured no power will flow from the inverter back into the utility system while work is being done.
However, the economics are awful. I check them every six months, and have been doing so since 2004. Although the prices of photovoltaics are coming down, my current estimate is that (admittedly in the UK where sun is limited) $1000 of the latest Kyocera PV cells will generate about $250 of electricity at current prices in their lifetime. During this time I will go through approx. $1600 of lead acid batteries (assuming a 5 year life). So my $250 of electricity will cost me a total including the electronics and the wiring of around $2500. (It scales because twice the cells means I need twice the batteries to store the output, so a bigger plant is no more economic.)
My guess is that at curent price decline, in about 5 years I should be able to use lithium cells with a 10 year life at comparaible cost, and the PV cost will have halved, so I may be looking at around $1250 for what by then may be $500 of electricity. Perhaps in 10 years it will make sense.
My suggestion: buy shares in either a nuclear energy company or a company building big wind generators. Seriously. Then you can tell people you are doing something positive instead of making a gesture.
From scarped cliff or quarried stone she cries "A thousand types are gone, I care for nothing, no not one."
if it doesn't seem so hard to you, then post some actual answers other than claiming it's not worth your intellectual super power
Also, turning the highly variable power from pedals into usable energy for electronics is quite involved. With a DC generator, the voltage varies wildly, and you need to regulate it to charge batteries. It is a big plus if your charging circuits make use of an ultra-capacitor (handles spikes well without wasting them). One site said to use a car alternator. This requires spinning rather fast to "get it started", but it does include a built-in regulator to charge a car battery.
The only company I've found to offer ready to use stuff offers a stand for your regular bike. This is far less efficient than a pedaled device with a flywheel. Exercise bikes are perfect - and typically come with generators these days - but only to power the display. No output. One company sells kids generator bikes - perfect except they are too small for me.
I can readily buy off the shelf stuff for car batteries with inverters. Otherwise known as a UPS. Where to get sinusoidal inverters? Is there a UPS with DC input and sine wave output? It is very inefficient to have to convert to AC then back again to charge the UPS batteries.
Net metering isn't the problem here. The problem is making sure you're not driving back into the grid when they meant to bring it down for service. If the guy in the cherry picker working up on the pole thinks your wires are cold, it's awfully rude (and dangerous) for him to find out that they're not.
The living have better things to do than to continue hating the dead.
Mother earth news covers stuff like this all the time. https://www.motherearthnews.com/ Wanna get off the grid, they can show you how.
Well, you can use photovoltaics for portable power for other applications around the house and on the roam, without getting into messing with your AC lines and stuff that really needs multikilobuck permitted installation. I have several small photovoltaic arrays set up to charge portable 12 VDC/120 VAC powerpacks. I use 400 and 600 watt Xantrex Xpower units to power lawn and garden tools, hand tools, and utility/emergency lighting. The 600 comes in especially handy for weedwhacking on the hillside >50' from the house. It also goes in the back of the Jeep with a folding PV array for on/off-the-road power (will jumpstart). And oh yeah, even last week, I was recording some improv tracks off of an analog modeling synth and digital recorder, powered by the 400. Down in a basement easy chair, too far from an electrical. outlet... Think distributed power systems.
" because I ordered a Tesla Roadster."
I want, no, I need a ride in your car. Please?
Need Mercedes parts ?
Onsite renewable doesn't have to automatically mean PV or electrical. Depending on where you live, you can cut a big chunk of your energy bill just using solar thermal. Modern vacuum-tube solar thermal panels can generate surprisingly hot water even on a cool, partially overcast day. Run radiant floor heating through several of your highest-traffic rooms to take the load off your forced-air furnace. Use the renewable hot water for showers, clothes washing, dishwasher, etc. Several companies have sites with online ROI calculators that let you figure out how much money this strategy saves.
Invest in a proper inverter, this is one of those things where you want the expertise of a professional engineer coupled with quality control and product testing.
Normally I'm all for hobbiest projects but this one has the potential to do serious damage if you screw up. If you put enough effort in to throughly test your prototype before using it you'll easily go over the purchase price of a developed product.
If you're going to do grid intertie, that implies that you're not talking about something trivial. Your meter works in kilowatt-hour units. A kW-h is about enough energy to run the background processes of the human body for about half a day. Running a single 100 watt bulb for an hour consumes a hundred of them. If you want to tick your electric meter one step backwards, it's going to take a not-so-unsubstantial level of effort to do it.
Let's not underestimate the safety issue, either. Feeding power into the grid when the grid is otherwise dead is tremendously dangerous - not only for the utility workers, but potentially for ordinary passers-by (imagine if a tree knocks the lines down, but the side that touches the ground is the side that comes FROM your house, with its grid intertied co-generation facility.
No, if you're going to do solar power other than to charge batteries, you're talking about a substantial amount of power. Generating that much power will cost you enough that the extra 2 grand for the inverter is line noise.
I got the impression that the author was looking more for alternative ways to use the power than "homebrew grid tie-in". For example, I used to run the vent fan on my greenhouse based on solar power. When the sun went down or when it was cloudy (i.e., when you didn't want the fan running), it'd stop. I'd imagine something like that would be nice for an attic fan setup, too.
Think of things in your house that you really don't need to run on grid power -- nonessential items. Perhaps, since this is just for a hobby, you could create a single dedicated socket that you don't use all the time that provides your renewable power to household devices. Your power could be fed into a battery, which would then be fed into a cheap store inverter. You'd want it to be on a switch so that your inverter doesn't run nonstop and drain your batteries, of course. You would, of course, have to have a battery back for such a solution.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
I would advise against trying to do a grid-tie-in as a hobbiest. It would introduce legal liabilities that you really don't want. That said, there is nothing to prevent you from using alternative energy to power devices locally and reduce your dependence on the utility provider. It is unlikely that it will be cheaper initially so I doubt that you will get net savings in the short-term but any device you take off of the grid will stop contributing to your utility bill. You can do this by using alternative energy sources to charge batteries and then using an inverter to power an isolated set of outlets into which you can plug whatever you have the capacity to power (based on your average charge and discharge rates). This would provide uninteruptable power as well and would be well-suited to your computer and related peripherals. How much you "save" (ignoring installation costs) depends on how much power the devices you place on your alternative "grid" consume. Note that local storage is a practical requirement for most alternative energy systems since they typically have variable output during the course of a day. Grid-tie systems avoid this by supplying utility power to make up for shortfalls and typically will not be eligible for utility subsidies if storage is present at the time of installation. You can also use a "tranfer box" which is a switch which allows connecting your "sub-grid" to either your back-up or utility power but never both. This allows the sub grid to use utility power if consumption exceeds capacity temporarily.
We all have a "free" source of energy.
Water pressure!
Simply build a small paddle wheel inside your pipes (incoming only - outgoing tends to get messy, and dirty electrons are no fun). Store that shit into a battery and run some lights off of it.
Okay, I've been interested in this for a long time and I read a good thread on the topic that I will put a copy of in this post.
But first I would like to make a quick point which is that this is a major political obstacle to alternative energy. It's not a technical obstacle, it's a political issue because we've "deregulated" utilities by letting them regulate themselves and this is insanity. At least it is one way to ensure that we remain bound to fossil fuel solutions.
So, on the topic of a DIY grid-tie inverter here are a few posts from a thread started by a guy looking to outsource the design.
Some dude makes the snarky remark about why don't you just pay the price and this is the response of a user named MarkM
(I've reformatted a couple of his posts into a single thread for readability.)
"Why don't you just buy one"
BECAUSE THEY ARE WAY OVER PRICED. That was yelled a the top of my lungs.
Solar panels cost about $4-5/Watt, inverters cost $1-2/watt. This is crazy. These grid tie inverters are no more complicated than a computer power supply which will cost you about $0.08/watt. The inherint nature of the grid tie inverters is to track the sinusoidal input and drive it to a higher voltage, thus selling the solar power on it. The IEEE 1547 require all kinds of hoops to jump thru and the inverter companies use this as an excuse to charge what they do. Again the hoops are simply jumped by a programed algorithum that monitors frequency and voltage levels. WOOOOO. I see this mans drive to find/build an inexpensive alternativ and do the gorella thing.
The way the grid tie inverters work per the regulatory hurdles is it syncs in on the line power voltage level and sine wave siganture. If power goes down it shuts off, no harm can come to the line man. This type of statement from you or utility companies is old school old day problems stemming from someone hooking a rotatry generator or non-monitoring piece of equipmnet to the line. And if a lineman is doing as he is suposed to he grounds live wires to ground before working on a "dead line". (that's a rule)
Utility companies have this power thing locked up and are going to be very reluctant to let small producers get in the game. Utility companies should not fear small producers they should embrace them and buy their excess power and resell it at a profit without any over head. The largest source of funds to build the power supply sytem is in the pockets of consumers: let consumers build it.
And as far as the regulatory cost as a part of the inverter cost that to is a pile. When the cost of regulation of a certain product is spread over the number of units sold it is small. Again we have a situation of free market and what the buyer will pay. In verter builders are maximizing there profits because competition is nill. I am all for free market but too I am for some of the Chinese or Indian products to slap the US, German and Australan made manufactures into a stop gouging mode.
The original thread is here.
http://cr4.globalspec.com/thread/4482
On the general topic of grid-tie inverters you may find the following Wikipedia posts of interest. You will find the following components mentioned in the documentation for many grid-tie inverters.
http://en.wikipedia.org/wiki/SEPIC_converter
http://en.wikipedia.org/wiki/Mppt
Thanks for the additional idea.
If the user is feeding power back into the grid, how will the contactor determine whether the power is coming from the electric co or the in-house power?
Yep, I never spell check.
More incorrect spellings can be found he
I've seen LEDs hooked up directly to 60Hz AC. I expected a flicker, but couldn't see any, and I get annoyed by monitors at 60Hz, so I'm not one of those people who doesn't notice it.
"When information is power, privacy is freedom" - Jah-Wren Ryel
That's a good approach. So what happens if, say, the grid goes open across the street, meaning you and your neighbors are on an isolated circuit and you're now driving their house, as well as yours -- how would that look different than driving into the grid while it was still up? Likewise, transitory opens or shorts in a windstorm might be detectable but how do you react to them? How long do you go offline? When it comes back up how do you synch up without mangling any of your electronics that rely on a fairly clean sine wave? (Not as much of a problem these days, what with switching power supplies in everything.)
Obviously it can be done, but it seems Very Complicated, and may be something where you want to have a commercial concern do the engineering so that if something goes wrong, you're not the one responsible. Because, let's be clear here: we're talking about generating lethal amounts of power and driving it into wiring that goes into other people's houses and into systems that other people are maintaining.
As for alternators, basically, an alternator is a variable three-phase AC generator. A voltage regulator controls the power flowing through field winding in the alternator, based on the feedback it gets from the charging system as a whole. If you replace the voltage regulator with a simple AC input line (stepped down so as to not arc over) you can get AC out that's related to the AC in, and use that to get phase matching. It's not pretty (given that alternators want to output three-phase) but it looks possible. I don't think it's a great idea, just tempting because junk alternators are cheap.
Nostalgia's not what it used to be.
Everything related to the grid will require engineering documentation and adherence to all kinds of standards and safety requirements. Best bet would be to use generated power for small appliances, etc. This will still reduce your usage from the power company but will cut down on the red tape + risk of disaster due to hardware failure.
Lurking in the desert
Considering the cost per kWh that it will be to generate your own, why bother?
The problem is that since you're feeding power back into the grid, how do you detect that the grid's down?
Just my WAG, but a grid-tie inverter has to generate a voltage slightly above the utility voltage so that power flows from the inverter into the grid, so you have to continuously monitor the inverter's output voltage and current. Then if the utility power suddenly drops due to a brown-out or black-out, the inverter's voltage should suddenly drop and current should suddenly rise as your inverter tries to compensate. You should be able to detect either one or both of these conditions and shutdown the inverter.
But that's just my guess.
www.xetenergy.com
we are designing a small grid tie ac inverter that is a per panel basis, basically you hook 1 panel to this unit and you have a mini grid tied system that syncs to the grid and shuts off if the grid goes down.
There are cheap solutions that will tie into the grid, but thats not really a DIY solution. A company that helps with paying for solutions is Carbon Solutions Group. Not sure how, but free money always helps.
The common assumption that this tech scales down to an individual level is a bad one. I'm not an expert, but I've heard experts say that, for example, the kind of windmill an individual can afford to build in his back yard will never pay back the energy that went into building it. I don't mean that it won't be economic (though that's also true) I mean that the energy costs that went into fabricating the components, putting them together, and keeping the thing working will typically exceed the energy that comes out of the windmill during its normal life span.
On the other hand, if a dozen individuals get together and build a big windmill in a really windy area...
No. this is for the same reason that when the grid dies, your UPS doesn't try to feed the neighborhood.
Yep, I never spell check.
More incorrect spellings can be found he
an open source project to produce solar power: http://www.solarnetwork.net/
It is amusing how easy it is to spot people who have never actually thought about the matter by comments like these.
The purpose of grid-tie is to avoid having to futz around with batteries. Batteries need charge-controllers, they need to be serviced, they have a finite life-time and they're either over- or under-speced because no two weeks will ever have the precise same power.
So you used the grid as your battery. It's as simple as that. You over-produce in the afternoon (assuming solar -- maybe in the evening for wind)? Just feed it into the grid. You don't produce at all in the night? Just take it right back from the grid. Here in the pacific southwest, loads peak in the afternoon when everybody runs an AC - so the power company will be more than happy to receive your added input. And loads are lightest around 3am, so they'll be just as happy to "give you back" your electricity then. Actually they're giving you cheap power in exchange for expensive power -- but in return you don't have to think about batteries at all.
In addition, with a grid-tie you're as scalable and as granular as you want to. Got some bucks to spend on a Panel this week? Great, you're now producing 5.37% of your household's electricity over what you were doing before. Without having to run new circuits or worry what consumer in the house will run on 5.37% of your total consumption. Without the grid-tie, you either produce all the electricity your fridge needs or it'll die. Or you change plugs whenever it's cloudy.
We're all born with nothing.
If you die in debt, you're ahead.
Found some of my old notes from when I was obsessing on this a few months back. Another way to search for information on this topic is to use the following Google search
"solar power"+"grid interface"
Apart from dozens of patent applications that are very helpful in getting an idea of how these things are built, that search pulls up all sorts of other info and one of them includes a book that is available in preview mode through Google books that goes into the topic in a general way. On page twelve he starts talking about distributed systems in the 1KW range rather than multi-megawatt systems.
http://books.google.ca/books?id=X8OXLvUSaW0C&pg=PT34&lpg=PT34&dq=%22solar+power%22+%2B%22grid+interface%22&source=web&ots=r56LpiTfmw&sig=jXJeZVV5NvkyleAbRZznUZqRWcA&hl=en#PPT7,M1
1. Hugh Piggott has been building windmills from brake rotors (drum brakes) and plywood for decades. If you have the room, take a look at his books.
2. Savonius windmills also seem to be efficient, according to the Internet, but I have not tried it.
3. If you are lucky enough to have running water, look into micro-hydro-power and micro hydro generation. Water carries a lot more punch than air. Some people even use micro hydro on drain spouts from gutters on their roofs.
4. The real efficiency is not the percentage of the power in the air converted into electricity. The real efficiency is the cost per watt. We only care about efficiently using scarce resources. Land area to put up wind mills or solar cells is abundant. Money to finance these projects is scarce.
5. You use a lot of energy you don't see in water. Try collecting rain water off the roof and trying to use it in selected areas - flushing toilets, for example.
6. Big money people live grid-tie systems. I would rather power a bank of 12V batteries under a computer desk, and run my laptop & accessories off these batteries. If I don't generate enough 12V power, I can always plug in a battery charger.
7. Small-scale (100W) solar systems are available, from Northern Tool, Harbor Freight, Fry's etc.
8. The only economically viable "alternative" energy system I've seen is solar-thermal. 90% of power plants use heat to boil water and create steam, then they run turbines off the steam to generate electricity. You can do the same with solar heat to boil the water, but it's tricky and not safe for idiots.
9. Solar heating & solar hot water are possible. Take a look at the black tanks to pre-heat water that some build.
10. Learn to charge batteries - it's not as simple as it sounds. Learn as much about batteries as you can. I like 3 loads: emergency (red,) normal (yellow,) and dump (green.) The red socket will remain on if I have any power at all left in my 12V battery (i.e., if V > 12.0v.) The yellow socket will remain on if I have normal amounts of power, but it shuts down when I get close to being dead (i.e., V > 13.5v.) The green socket only comes on when I am dumping power (i.e., V> 15.0v.) Of course, you have to build hysteresis into this system or you get crazy on/off flickering. The dump load may be to run an air compressor or to pump water up hill, or to run a space heater / ac unit in an unused shed. If you don't have a dump load, you will overcharge your battery and ruin it. You also need to cut off all power at some voltage to avoid ruining your batteries.
11. Ways to store energy (other than batteries) include compressed air and pumping water.
Andy Out!
I have friends of mine that are going to spend over 30K on solar cells. They will get something like 10K support from the govs. I suggested that since it was a new house that they put in geo-thermal heat pump, but they said no. Instead, they have gas heat (fine), and regular AC (not so fine). It is the AC that is causing this high need. Had they picked the GEO-thermal, it would have cost about 4K more than the other 2 (at time of construction), but would have used about 1/3 less energy. IOW, they would have saved 8-10K on the cell needs. Oddly enough, they still would have gotten the same amount back on support.
I prefer the "u" in honour as it seems to be missing these days.
Someone needs to make and publish plans for a good Stirling Engine that can operate in the temperature range of heat-pipe solar collectors like the ones produced by Thermomax.
http://www.thermomax-group.com/
Very robust systems that can heat or preheat your hot water can be made with heat-pump collector elements and very few additional moving parts. If you add Stirling Engines that can work off of hot water, then you can also get electricity generation in the bargain. That would be awesome!
Yes, but... see my other replies in this thread: what happens when the grid dies because of an open somewhere upstream quite a ways, so suddenly your system sees a jump as you're now powering your neighbors' lights. Do you shut down because of that jump? How do you tell the difference between that and when you've just turned on your dryer and there's an enormous inrush current into the dryer coils?
More importantly, once you have, on your own, decided how to tell the difference between big transients happening in your house and big transients happening because the grid's crashed and you're now driving someone else's house, or possibly a lineman who is trying to fix the fault -- how do you justify the decision process you used to make your machinery do what it's doing, and how do you justify that to the utility company or a judge when you're charged with negligence or even worse manslaughter?
Obviously this is a solved problem, technically speaking, but it's not clear to me that it's a problem you or I as individuals want to solve with something we've cobbled together.
Nostalgia's not what it used to be.
If the guy in the cherry picker working up on the pole thinks your wires are cold, it's awfully rude (and dangerous) for him to find out that they're not.
Everyone working in a cherry picker assumes the wires are hot until tested to be cold, then once tested to be cold, still treats them as hot (gloves, etc.) whenever possible. Those that don't, don't last long.
Learn to love Alaska
The best way to lower your bill is to simply use less electricity. Compare the cost of a 100-watt setup vs. the ease of eliminating 100 watts of usage.
But if you still want to generate your own, don't go grid-tied. Charge a battery bank, and use that to power or charge things like cell phones, mp3 players, laptops, etc.. Or use it with an inverter to run whatever you like.
Oh, you're not stuck, you're just unable to let go of the onion rings.
> Because, let's be clear here: we're talking about generating lethal
> amounts of power and driving it into wiring that goes into other
> people's houses and into systems that other people are maintaining.
This is the key part. I'm as Libertarian as they come but a power grid implies a need for some sort of standards and real enforcement of same. Forget the legal implications for a minute, do YOU want to kill your lineman? Then don't conduct unannounced experiments on the production power network. Ya got three choices here:
1. Man up and buy the commerical, TESTED AND CERTIFIED product for that key interconnection point.
2. Build a test grid, do your R&D and produce a TESTED AND CERTIFIED product of your own.
3. Restrict your alternative power experiments to those that do not require an interconnect to the grid.
Democrat delenda est
Take a look at a Milwaukee corded drill. They have ones with so much power that they have a 2-foot long side handle to help control the torque, and you can still cause yourself serious damage with them.
When you need real power, battery-powered tools just can't provide it. That said, they are certainly practical for many things.
For someone using grid power though, it's more efficient to use a corded tool. A cordless has a whole set of inefficiencies around AC/DC/AC conversion that the corded one doesn't, as well as self-discharge in the battery itself.
If America wanted, they could power itself via coal for the next 400 years (and that assume monster increases in energy usage). The problem is that fossil fuel is subsidized in a number of ways. There are direct subsidies via gov. payouts as well as indirect payments. The real subsidy is the deferred health issues. If you disregard the whole issue of CO2, coal and even American diesel is heavily polluting with heavy metals, particles, etc. While America DID clean up alot of our output, our diesel engines are currently allowed a free pass on any real pollution control. And Coal? Well, it the bulk of the mercury issue in our water is BECAUSE of coal plants from all over the world. If Coal power plants were required to clean up everything except for CO*, the costs of power would be 2-5 x what nukes are.
I prefer the "u" in honour as it seems to be missing these days.
I see your point. As a point of fact, my eventual goal actually is to go all out with the grid tie-in, and mostly for the reasons you detailed.
I still stand by my opinion that once you get into that level, you're beyond the "hobbyist" point. You're talking multi-thousand dollar pieces of equipment, permits, contractors, inspections, contracts with the power company, and potential liability if something goes wrong. That doesn't sound like a "hobbyist" project to me.
What does sound like a hobbyist project to me, is building a homebrew windmill, using it to charge a UPS, and using that to power, say your low-voltage garden lighting, and your garage lighting. This is what I have installed currently. I've got capacity to add a bit more load to the system, so I'm currently deciding on what's getting wired in next. Then it will probably be a second windmill, or an upgrade to the current one.
I agree with everything you're saying, and do plan to go that route myself eventually. Please don't misunderstand my comments as saying it's all a bad idea. I just think it falls outside the hobbyist scope.
And speaking for myself, I would have never gotten interested in going that far if I hadn't started out small by building that little windmill out of a leftover motor and seeing what I could do with it.
Each state can of course choose to do things differently, and what you need to look for is what rate you get from the power company when you sell it back vs what you pay for their power. Some states force the power company to pay the going rate for power, which means you sell to them when the price is high and use it at night when the rates are lower. But, if you generate more than you use, you usually loose.
Check your own states law on net metering here http://www.serconline.org/netmetering/stateactivity.html.
For those who are really serious about doing something with alternate power technologies I would suggest this site: http://www.homepower.com/home/
As an alternative, you can also add the ability to power the house completely from your renewable energy source. Just add another manual switch. If the power goes out, just flip a switch and you'll be back up and running!
violations of electrical code, building permits and stuff like that. If you want to experiment, don't do it with the in-house wiring.
If you are talking about a small project, you won't actually run anything solely on solar, but instead want to make use of your solar power. You'll use grid at night, and even partly during the day.
What could be done -- though it is not available off the shelf -- would be to make DC power supplies which take as input both grid power (in-only, no feeding back) and the DC output of solar panels or other sources.
Such power supplies would combine the two sources, taking all the solar power and as much grid power as is needed to meet the load. For example, a useful tool would be a PC power supply into which you could plug in AC but also the output of solar panels.
It is actually important that the panels not generate enough power to completely power your load, believe it or not. If the panels can power the load away from noon, it means at noon you are just throwing away the extra power. Solar is not economical yet, so anything that throws away power (such as inadequate load, or off-grid systems which throw away the power into already charged batteries) makes it really not economical.
Grid tie systems solve this problem by putting the extra capacity into the grid for others to use. You won't be doing that.
However, if people made DC power supplies, especially for PCs, that worked like this, it would allow the full use of small solar panel systems.
However, usually there is no rebate unless you grid tie, again making solar not economical. (And this is usually wise. Off-grid solar is highly wasteful but when it's the o nly choice, people don't need a rebate to make them buy it.)
Has it been over a year since you last donated to the Electronic Frontier Foundation
Homepower magazine used to have a feature called guerilla solar. small scale projects
OOO
First, the solar comes in, and needs to be converted from 24VDC 10 amps to 120
Then it needs to be synced using a miniscule amount of AC to "seed" the signal. It's not that easy,mostly because "syncing" has to be done w/in x% tolerance if IIRC, and it has to handle large loads, be surge protected, and damn near lossless. (5% loss on a 600W setup (which is only 600W @ noon if your in arizona...) is 30 watts, and your more likely to be higher than that)
As for the OP,
You won't normally backfeed to the grid w/ that small amount of power (the power you generate will get used by your house, so you'll just use a little less from the grid) Except if you live in an area w/ full sun, sometimes in the summer you might spin backwards during the day if your not home, and the fridge cycles off.
Most places give you two credits, one for generation (backfeed to the grid), and one for production (everything the panels make) So if you do a gridtie w/ a capacity capable of more than 1200 you can see paybacks pretty quick, and add more panels as you need.
Depending on where you live, you may reduce your bill very little (like a nickel)in the winter, and a "noticable" amount in the summer, or it could be a lot more, w/ just 600W worth of panels. Panels will be cheaper, inverters will not for a bit.
You can often find inverters on Ebay when people upgrade too, that's where I would go as a hobby activity.
How much is your data worth? Back it up now.
I agree. Grid-tied is way too much complicated for the hobbyist.
Maybe an heavily modified UPS with external battery bank and solar/wind recharger is an better solution. Getting rid of major home energy hogs, and changing the habits might help too.
Well... going green eider hurts or just costs much in invested work or money.
If the goal is just to experiment a little with alternative power... why tie into the grid at all?
You could put in your power source (say, a solar panel) and an inverter and any batteries etc you want, and have an electrician hook it up to one outlet. Or maybe just a few. But, keep them totally separate from your regular electrical system. That way, you could experiment with your alternative power on a few outlets, and keep the rest of the house on the regular system, and not have to be concerned about the technical details or legal concerns of tying your "experimental" energy system to the grid.
I'm considering that I may do this in a few years. I plan to examine how much energy is used by different appliances, what solar equipment will cost, and try to apply solar power to 1 to 3 top energy consuming items in my home. It won't connect to the grid in any way, and I'll just have the "solar outlets" in one spot and the rest of the house on the normal grid.
what happens when the grid dies because of an open somewhere upstream quite a ways, so suddenly your system sees a jump as you're now powering your neighbors' lights. Do you shut down because of that jump?
Again my WAG is that if the load from your neighbors' lights is more than your inverter is putting out, then your inverter's output voltage will quickly drop as it tries to compensate for the increased current draw. If the load from your neighbors' lights is less than your inverter is putting out, then your inverter's output voltage will quickly rise to try to compensate for the reduced current draw. Remember, at any given time your inverter is trying to push a constant "X" amount of power from your solar array or wind turbine into the grid by maintaining a dynamic balance between voltage and current.
Maybe if your neighbors' lights were drawing exactly as much power as your inverter was putting out, then your inverter wouldn't notice, but I can't imagine that balance lasting very long. As the power from your solar panel or wind generator constantly changes as the sun and clouds move and the wind changes, so does the corresponding amount of power your inverter tries to feed into the power grid.
More importantly, once you have, on your own, decided how to tell the difference between big transients happening in your house and big transients happening because the grid's crashed and you're now driving someone else's house, or possibly a lineman who is trying to fix the fault...
Most transients from motors kicking in and stuff are going to last some fraction of a second and can probably be safely ignored. Any transients, brown-outs or loss-of-power lasting more than a second or two should probably cause your inverter to shutdown. My understanding is that a grid-tie inverter must measure at least 5 minutes of stable utility power before it starts trying to feed power to the grid.
There is apparently an official document that specifies the proper operation of grid-tie inverters; I've never seen it but I'd like to.
...we're talking about generating lethal amounts of power and driving it into wiring that goes into other people's houses and into systems that other people are maintaining. You make it sound like a bad idea.All rites reversed 2010
The answer seems simple: do not connect the charging system to the grid.
If the system is to generate "only a few watts" I'm not sure that it can supply enough current to household's main loads. It might be more efficient to purchase more efficient appliances or change power usage habits to be more efficient in the long term. Locating the biggest load and reengineering usage or replacing it with a more efficient model would be more economical then generating a few watts here and there. Where is the cost analysis and break even point?
They used to actually do that for electric trains back when there was a debate about ac vs dc power. The problem is that it wastes about 3/4 of your power - each large motor will be about 50% efficient.
What would happen if every house hold was designed with solar panel power/etc feeding back into the grid, across the entire power grid? Wouldn't that cause some significant savings for the whole system, and possibly save some environmental issue or other, as the utility wouldn't have to generate as much power?
This is exactly why you want to buy a real isolating inverter and not try to make your own.
If the failure is isolated to your circuit from the power company (like if the transformer at your pole fails), then your circuit would never detect that the grid power went down if your home power system is producing enough power to feed the grid -- since your home system is tied directly to the grid, it would also be powering your 24AC transformer so would never see the grid side go down.
So, when the lineman goes to fix your transformer, he's dealing with a live circuit from your house.
Real isolation inverters look at the waveform and frequency to determine if the grid is offline.
Having a hobby power system is a great thing. You are providing your own power, independent of commercial producers, and in many cases its non-polluting, sustainable energy. Grid tie-in means you are generating enough power to sell to others. Its a business and not a hobby. My brother has a small acreage (5.5 acres), 15 miles from the city. He has 6 large solar panels. They are about 5 years old and each panel puts out 75 watts (450 watts total). He also has a wind charger that put another 600 watts into the system, for a total of 1050 watts on a sunny windy day, or 0 watts on a still night. He hopes to run a few appliances off the power (assuming he can put full power into the system 20% of the time on average, he can run a 210 watt appliance all day). If he had a geothermal well, putting water into the ground and getting high pressure steam from a connected well, and use that to turn a turbine/generator and produce several hundred kilowatts 24/7, then he would have something worth having a grid tie-in. Then he could sell the power directly, or generate hydrogen and oxygen, store it, and use a fuel cell with a power oscillator and a phase-locked loop circuit to match the power grid frequency to the power oscillator (you need to be in phase to within an angular distance of 10-9 radians for the power company to be happy). Remember 1 Megawatt with an error of 10^-9 radians means a power loss of power of at least a watt (not bad, but why heat wire?). And the power loss is the power the company is making and the power you are making canceling out. Certainly being pi radians out will give 100% loss (all the power you make is being canceled, and you are killing that much power again made by the power company). Watch the wires melt. There is a massive difference between the two. If you mean 'grid tie-in' as in 'if my power goes down I can still rely on the grid', then its an emergency backup system, not quite a 'grid tie-in'.
Easy... (I think).
1. if you are using a car alternator that is getting it's energizer current from the grid, once the grid goes down, the alternator will start to free-spin, and won't produce any power until the grid comes back up and begins to energize the coils again. The alternator cannot produce current without a voltage source to feed the coil. (Hence why you need to let your car run for a while before removing jumper cables if you are that unlucky.)
2. If you are using a permanent magnet / solar / fusion / etc generator, then you have two options. First, have it spin a motor which spins an alternator so #1 above is correct. Second, if you can resolve a way to match the frequency, phase, and voltage, how about you just have a relay that will disconnect your power generation system from the grid every x seconds for 1/10 of a second, look for voltage on the grid, and if it is found, re-energize the relay. If you have the inverter portion stay connected, but just remove the inverter's feed, then the inverter would not need to be re-synchronized.
3. The frequency of 60 hz on the grid is maintained by computer control to ensure that all of those old AC clocks that monitor the frequency of the wall current will always show the correct time. So, you can be guaranteed that the power generation station is going to be maintaining somewhere between 59.999 and 60.001 HZ. (Give or take). If you use the GPS system as a time reference (It is governed by atomic clocks) to tie into a frequency counter, you would be able to monitor the frequency on the grid. We will assume that any inverter you build / buy is not going to be super-accurate, so the frequency will drift. If you can detect this drift, then you know you have lost your reference from the grid, and you should have the system shut off.
Build your own wind turbine, put solar on your camping trailer, etc.
http://otherpower.com/
"If you're not passionate about your operating system, you're married to the wrong one."
Most cell phone batteries use 3.7 Volts DC Lithium Ion batteries. Different cell phone may have batteries of different shape, different charge connection, and different capacities. But as long the battery is 3.7 Volts DC Lithium Ion these battery can be charged by applying a constant voltage of 4.2 Volts DC. You can use a small solar panel to charge the battery you may need a voltage regulator to regulate the solar panel to 4.2 Volts DC, which is not that hard to build.
ricanboy15@yahoo.com
Gotta pay to play. If you want smaller, you are in league with all those homebrew hacks you found on google.
I run air through a duct loop through the cellar I set up, a sort of homebrew geothermal heat exchanger, and the cooling effect is actually fairly dramatic. So there's always stuff like that.
I don't need no instructions to know how to rock!!!!
Use your renewable energy thing to recharge something the works with batteries.
Just buy an other battery and keep it plugged to the recharger,
linked to your renewable thing.
Example: buy an eletric scooter/bike, take an extra battery, while you are around with it keep the other battery on charge with some solar cells.
When you came home switch the batteries, and so an other day goes on...
Easy and rewarding (for me as well, as I won't breath gas from your car).
I like the way you think. As I said above, my motivation is more about reducing my "checking account footprint" than it is about reducing my "carbon footprint".
That said, during this whole discussion, I've started to wonder if it might be better, for either motivation, to focus these efforts all into a single outlet for one of the plug-in hybrid cars that will be appearing on the market shortly.
Solar charged batteries are not very green, you only do them if there is no other option. That's because you don't want to keep batteries in permanent discharge, you want to fill them up regularly.
But once batteries are full, your solar system is usually just throwing away power unless you have another load for it (in which case how were you running that load while charging?)
Solar power only makes sense if you take 100% of the power the panels make. You can't throw it away the way battery people do.
Has it been over a year since you last donated to the Electronic Frontier Foundation
A variant on the of idea partitioning off load(s) into a isolated circuit:
Partition off enough load to approximately match what you're generating. Wire it solar -> battery -> inverter -> load. When the load needs more than you're generating, augment it with powerline -> efficient DC power supply -> your battery.
There's a double loss of going through two conversion steps when pulling power off the line (hence the goal of approximately matching your solar output). But it should be perfectly safe since a power supply can't push power back into the line.
Bedini, Tesla, Meyers, Puharich, Stubblefeild, Bearden, Pantone, and many more to read about energy and cheaper ways to produce it yourself. As in anything, If you want it done right the first time, you have to do it yourself. Most people today would rather buy a product instead of learning and doing. The automobile is a perfect example. How many of you who drive know how to fix your own vehicle? As an energy hobbyist, may I suggest building yourself a Bedini "School Girl" motor. It's called a school girl because it's so easy to build, a school girl can do it and did. Welcome to the world of energy!
Ah,
That's really a great question - how in short - do so many AC generators all cooperate together to feed a synchronized grid?
When you figure this question was solved some 100 years before the first transistor, you can begin to appreciate how fundamentally simple, and yet tantalizingly obviousness the solution actually is.
What was used is a centrifugal steam value. When the turbine is spinning too slow - which occurs when the demand for energy exceeds the supply - the valve opens and sends more steam to the turbine. The generators will turn in lock step with the grid, if the experience a load, they will DECELERATE the grid, if they experience a power input, they will ACCELERATE the grid frequency, as each generator experiences the frequency in speed-of-light time, the system communicates the load situation in real time - all demands send a signal to all the turbines to pass more steam.
Now to islanding.
If you want to know what percent of the total generating capacity a single input represents, you vary your power output by five percent in either direction and measure the effect on the grid frequency. If you are the only generator, the effect on the grid will be five percent, if you are the tail on the end of a much larger dog, the effect on the grid frequency will be negligible. To put this another way - you inject a signal into the grid and see if the signal is absorbed by the grid, or not.
Hope that helps,
The rules and requirements for grid-tie are there for a reason. Part of the cost for said system is the testing and validation that the safety circuits work (i.e. will interrupt w/o arc-welding shut in a surge, etc.) At best, a homebrew system violates the code in your area and you could be liable for connecting such to the grid. It also gives the power company more reason to distrust grid-tie ("see, we told you people would do this...") At worst, you light up a lineman who is trying to repair the system after a storm. The disconnect HAS to be certified. If you don't want to buy a commercial inverter, then buy a generator disconnect (but then you aren't grid-tied, that's an either-or). As for synchronization, if you are putting power on the grid out-of-phase with the grid, you will be really popular with your neighbors, really fast. Within the reach of your generation, you won't be at 120 vAC RMS anymore. If you grid-tie you are on the grid, period. Electricity flows where it wants, your power becomes others power. Your grand experiment is involving others, if they want it or not. Please tell me where you live, so I can isolate my house before you do this.... Now, if you want to experiment OFF the grid, that's really cool, and go knock your self out. Just don't include others in your experiment.
IANAEE but I used to work on car alternators for a living. One problem you may run into trying to synch alternator output to the grid is that alternators have a triple-wound stator that produces 3-phase AC current. That makes for much less ripple in the rectified DC and simplifies filtering. It's also the cause of the "alternator noise" you sometimes hear in poorly installed car audio systems.
This ain't rocket surgery.
what about hacks for those with grid-tied systems and want to add hacks to the system like wind or sun powered sterling engine? You know, to boost what the solar panels don't cover for electric usage. Another hack would be grid disconnect and some kind of grid faking scheme so the home still gets to use the solar energy there when the grid goes down?
Those inverters may be expensive but they do a nice job of providing good sine waves and protecting linemen from back powering when the grids is offline. Hacking addons for those seems like a valuable thing to do and probably safer. Well, except for the 300VDC input voltage levels used. That can smart a bit before you don't know what hit ya.
I work for a Utility in their Protection & Control department...DO NOT use a home-brew approach to do this if you are anywhere serious about other people's safety. If someone does get hurt, the utility will probably be able to find out where the power came from (especially if they have 'smart' metering in your area). Transformer work in both directions - they step up, they step down.
That said, what you're proposing is theoretically doable. Your best bet, as some posters already pointed out, is to go with the expensive (i.e. tested and UL or ULc approved) equipment or install the equipment on an isolated circuit. The people who mentioned HomePower Magazine have a point...but I believe the product was called the microsine (uSINE?) inverter and was specifically designed and tested for this application. The manufacturer was Trace (I think they have another name now though). You may be able to pick up some used ones (or other kit) on ebay or something similar to reduce your costs.
I've worked in across the country here and everywhere I've worked you require that the installation be installed according to the local electrical code. NEC in the US, Provincial in Canada (I think each province has their own code there). HomePower Magazine is a great resource for renewable energy in general. I'd recommend it to anyone interested in the topic (I've been getting it for years).
Why the focus on grid-tie electric. It is much easier for a hobbiest to get involved with solar heating/hot water.
It's possible to build a hobby solar electric system for well under $1000 including batteries, charge controller and inverter that can provide a reasonable amount of AC power for limited equipment. I have a small single panel system that produces about 15 kWh a month. There are never times when I would generate enough electricity to sell back to the power company (unless I unplugged the fridge and every device on standby throughout the house in the middle of summer), but I do have a couple of "special" AC receptacles in my office that run my laptop and other small devices. The limiting factor for me is the power inverter - I have to be careful not to get too greedy. I always have the option to use grid power, but I rarely need it in my office environment for anything but the overhead lights and "always on" devices like my wireless router and DSL modem. It was a fun way to get my feet wet with solar, but I wouldn't consider a larger installation with current technology (I'm too far north and there are no exorbitant gov't grants available to me in this area to offset the installation expense).
Hi, I would recommend a small off grid system, say JUST for running the computer. You would need at minimum a 1kW system: #6x 170watt solar panels [total 1020 watts]. #Roof mounting hardware. #Low voltage wiring. #Charge controller. #Battery banks. #Inverter. This system depending on how much sun insolation in your area would give you about a minimum of 120kwh/ month during winter. you could size it larger depending on your needs/ wants and the amount of money you want to spend. The price my company sells these for is about USD7000, so it may not be cost effective. An alternate suggestion would be to buy a smaller version just to supply all those wall warts around the house. you might be able to do that for your USD2000. perhaps a 200-400watt system might just be right for you. A grid tie system is NOT for the hobbyist!
You realize that a grid tie inverter is the opposite of a computer power supply don't you? They don't even have to consider phase, their output doesn't HAVE a phase.
Meanwhile, the non grid-tie inverters often output stepped voltage rather than a sinewave (and so harmonics). It's cheaper by far and good enough for many applications, but not for feeding into a big iron core transformer. They don't care about phase either. They just need to be somewhere close (ish) to 60 Hz.
They may still be overpriced, but not by 25 times as you suggest.
Given that a UPS makes a distinct clicking noise when it switches over, I'd say it's relays.
I'm playing around with solar power myself on the cheap and there are a number of very worthwhile uses. For example, Ebay has a large number of sellers selling LED downlight replacements, (MR16) that draw around 100ma while producing a fairly large amount of light, although the angle is much narrower and whiter than halogen downlights. These generally are from around $5AU to $25AU depending on power rating.
There are also a number of intelligent (micro controlled) solar chargers, a good charger is critical to getting the best possible performance out of the cells, while keeping losses to a minimum, and also charging the batteries for maximum life. These are around $80-$125AU. Cells themselves are very cheap, now, Oatley Electronics over here sells a complete 100w package among others, with a battery and rudimentary charger.
Batteries can be obtained cheaply, I use electric wheelchair batteries rated at around 12v and 35 to 45amphour. These are designed for deep cycling and are usually replaced when the chairs are serviced, regardless of the condition. Batteries from auctions for commercial UPS'es are also great, usually 2v at around 100-200amphour! Just don't short them, can be very nasty.
I'm slowly adding additional standard downlight fittings to all the rooms in my house, and fitting LED downlights to run off (two at the moment) solar cells hooked up to a smart charger/regulator and 12v cells. No electrician required, no heat, very minimal expense, doesn't affect existing wiring, although clearly marking the cable runs is advised for safety. Long term i'll be hooking up to the solar system a ventilation system throughout the house to help with moving stagnant air from inside wardrobes, etc to cut down on any mildew problems in winter. As well as overhead fans during summer to help with circulating air.
All up for 2 x 12v 20watt cells, 20 odd LED downlights, a smart charger/regulator, and 3 x 12v batteries, i'm out around $450-$550AU. People might argue that if would ages to recover that cost in the electricity bill savings, but this isn't about just that, I can now also do things that I wouldn't normally do with standard electric powered stuff because the cost now is nill.
Simply make or buy from a boat or RV supply a Simple Auto Transfer switch with delay (most rated 30 to 50 amps). Set up your inverter to supply the shore/utility side and the utility to supply the emergency side. Now power some circuit ( a good idea to have a fuse in line for circuit protection) with the load side. When the sun is shining the power comes from your inverter, when at night, or no sun, the utility picks up the load. The reason for the delay is to prevent cycling if the power interruption is temporary.
Matt's addition to Occam's Razor:"The most simple answer is preferred by those that are simple."
A UPS tries to run on wallpower if it can, but uses battery if there is no wallpower. I want an inverter that is sort of a reverse UPS. I want it to run on battery if the voltage is good but switch to wallpower if needed.
This way I can use solar power if I have any but my stuff (window AC, microwave, whatever) will still work when the batteries are too low. It has to be a bit smart not to switch back till the voltage gets above some threshold.
Is there such an inverter? What is this type called?
This is called Guerrilla Solar. Home Power magazine used to run spotlights every issue although I've not seen one in awhile. Folks would show off their systems that had been setup without their power company knowing about it.
You're better off isolating some room for use with this small scale stuff if the cost of a certified approved and TESTED inverter is too much for you. Yes, these things are expensive but they are also heavily tested for long term use by labs to ensure they don't burn your house down in some odd failure mode or kill a guy up on a pole. Yeah, the guys on the pole are supposed to know better; somehow knowing that wouldn't make me comfortable if someone died because I was too cheap to do it right with a known good tested piece of hardware.
Stick to powering something off grid and get used to managing loads, charging batteries, and maintaining your power source if you cannot do it bigtime to start. As you get comfortable with it maybe commit to something more expensive. Screwing around and possibly hurting someone does no one any favors when others want to grid-tie. Some of the existing codes are onerous enough without mistakes forcing municipalities to make it even harder....
Build it, Drive it, Improve it! Hybridz.org
Not only that. $2000 for the shiny pre-certified one.
cost of certification from in independent lab, what? $20,000+ ?
thx e
If you really want to do it as a hobby then probably your best bet is to stop looking at electricity all together. After all electricity is just a transportation mechanism for energy. An air conditioner doesn't even need electricity for instance. The primary component is the air compressor which could be run by anything from a wind turbine to a water wheel.
What's going to be most useful changes based on what you want and your environment though.
...of a small, old (ca. 1909) hydro plant belonging to a major utility. When they reconnect it to the grid, they get the voltage and frequency in the ball park, and then 'throw the switch'. The friend showing us the plant used a fist hitting the palm gesture to describe the moment of reconnect. Apparently, some imprecision is tolerable.
...Lorenzo / I'm into kinky crustaceans. I just discovered internet praWn.
Another thing to remember is doing anything on the central power grid that is not "clean power" can cause serious issues just while the grid is running. If you do some cheap tie in and manage to feed some strange harmonics into the grid, you can short/interfere with/destroy electrical equipment in other locations. Power companies generate clean power and sometimes just hooking the wrong equipment to a grid can create harmonics that can reek havoc. Doing a small hobby at home separate from the grid, play all you want. If you are tieing stuff to the grid, make sure you understand it 100% or just don't do it for so many reason.
This is a good recommendation. You can put in batteries and a panel or two, a windmill, etc, and hook them to a standard inverter, and use them to (say) take your laptops off the grid, or run the CFL lights in your office. No matter what you drive with it, that's electricity you won't use from the grid. In the end, unless you produce more than you use each month, either way is a wash.
However, I've seen systems that used DC battery storage with a grid-tie inverter that connected to the house wiring with a standard plug.
One possible means of detecting 'grid down' status would be to watch a different phase than you're feeding (presuming you're not matching all three phases, right?). Just a thought.
our phase generator v.s. chillers 2 miles away at a grocery store. That was an expensive learning experience. they didn't say anything about that in Engineering School.
Sure. You anywhere in the midwest?
go to http://www.homepower.com and feast on what the little folks are doing.
Also, go to http://www.instructables.com/group/solarenergy/ to see what the do-it-yourself crowd is up to.
I hope that this helps.
Al Yelvington
Arlington, VA
If you want to reduce your energy bill renewable energy, especially solar PV is not the way to do it.
If you're in any way a typical US resident then you live in a draughty, poorly insulated wooden box with an antiquated air conditioning unit that's run as a heat pump in winter; a fridge big enough to keep a body in from the Regan administration and incandescent lighting.
Before you look at spending money to generate more electricity look at how you're using what you already have. Insulate your home, buy smaller and more efficient appliances, use efficient lighting and get a washing line and stop using the tumble dryer, paint your house white and get the most efficient AC you can afford.
Once you've cut your consumption to manageable levels then look at deriving some energy from renewables. Start with heating loads, because they consume far more energy and are far more cost effective then electricity generation.
Get a wood stove for winter heat. Then look at solar thermal for water and space heating which costs a fraction of a PV installation and actually pays for itself in a few years. If you live somewhere warm you can easily DIY with some glazing, black paint and old radiators. Maybe make a biogas digester and use it to run your gas cooker.
Once you've done all this you can start thinking about generating your own electricity. If you're lucky enough to have a river or stream on your property then you're incredibly lucky because small scale hydro is cheap and reliable. If you live in a windy area think about wind power. If you don't have either then think about solar PV. Don't try to grid tie or convert the entire house unless you have a huge installation. Have a separate circuit run off a cheap inverter to run non-critical loads like lighting, fridges and suchlike.
So, basically, you're doing it wrong.
I haven't tried what this website says, but http://www.electricitybook.com/ claims to be able to show people how to make all their own electricity. It looks like it uses used vegetable oil - no rainforest would be cut down or food supplies reduced to supply your fuel - so is green with no negative consequences. Good luck with whatever you try
Good luck sometimes arrives disguised as bad
The idea I had was to try to use electricity as it is generated rather than storing it and using it for later. Rather than making a backup power system, just try to co-generate to reduce your electricity bill.
For instance, get a solar panel, a single 12V automotive (deep cycle) battery, and a 12VDC marine air conditioner. You can buy a device called a voltage relay that will turn on when the voltage in the battery reaches a preset value (like 13V) and turns off when it drops below a certain value (like 11V). Sun shines the most in summer, when you use the air conditioning the most. So when the sun is shining, the air conditioner runs, and cools your home. It won't be enough to keep your home cool by itself, but it will reduce the amount of energy you use for your regular central air. The advantage is that it doesn't require an inverter, and it's not tied to anything else in your house (no 120VAC). In the winter, it should be relatively easy to find a 12VDC heater instead of the air conditioner, and you'll reduce your heating bill a little. Of course, in the winter, there's far less sunlight to go around.
"I have never let my schooling interfere with my education." - Mark Twain
Grid-tie inverters need type-approval, which is part of what makes them expensive. If you just want 230 volts and 50 cycles a second, and you don't care much whether your crests and troughs align precisely with the local electricity board's crests and troughs, then just use an old UPS (or several). These can be had dirt-cheap when the old batteries are no longer capable of holding a charge, but your local scrap metal merchant will buy them off you for the lead they contain. It's simple to modify a UPS to make it into a straightforward inverter; all you need to do is disable the charging circuit and trick the mains-sensing circuit so it always converts DC from the batteries into AC at the output (you probably want to leave the low-battery-voltage cutoff in place, though). Just never plugging mains into it might even do all this for you.
Begin by counting your watts, checking the ratings plates on all your appliances. For lighting, you only need something like 42 watts per occupied room (20W in the ceiling rose and perhaps one or two 11W lamps). A refrigerator needs another hundred or so. Water heating, when solar power is not sufficient, probably is still best done by the mains.
Once you have decided what you can safely run from your UPS (and by the way, it's not a bad idea to under-run it: ordinarily, a UPS will only run from batteries until a generator can be plugged in instead of the mains, or for long enough to do a clean shutdown. The real limiting factor is your auxiliary generating capacity) then you can split your circuits as follows.
Install a second consumer unit and two contactors, one of which must be fitted with an auxiliary N/C contact. Wire this auxiliary N/C contact in series with the coil of the other contactor, so only one of the pair can be energised at any time (this gives you, in effect, a big change-over switch). Consumer Unit One feeds your heavy-duty circuits (water heater, shower, cooker and so forth) straight from the incoming supply from the street, and also supplies the inputs of contactor number two (the one) via a suitably-rated MCB. The coil is fed by the aux contact of contactor number one. Consumer Unit Two feeds your lighting circuits and everything else that's to run on locally generated power, from the outputs of the two contactors joined together. The input to contactor number one, and its coil, is fed from the UPS.
When the UPS is running, contactor 1 pulls in and supplies power from the UPS to consumer unit 2. The auxiliary contact in contactor 1 prevents contactor 2 from pulling in. When the UPS is off (perhaps because its batteries have run out of juice), contactor 1 drops out. The coil of contactor 2 is now fed from the mains, via the aux contact in its closed state, and supplies power from the mains to consumer unit 2.
I promise, it will all look much less complicated if you draw a diagram.
By the way, if you have central heating: A water-cooled diesel (i.e., cooking fat) engine can be plumbed in place of (or in series with! The boiler's thermostat will prevent it from firing up as long as the engine is heating the water enough. But if you do this, add a 3-port valve to short-circuit the engine when not running, so it doesn't sink heat from the boiler when that is running. The boiler shouldn't sink too much heat from the engine since its heat exchanger has a lower heat capacity and anyway, you aren't paying for the waste cooking oil) your boiler and used to spin a hefty alternator for battery charging. (Arrange it so the valve is normally short-circuiting the engine, but moves over to allow circulation when the engine is running. Diverter valves only need about 6 watts maximum, so you probably can use a separate, small inverter to power it; note that
Je fume. Tu fumes. Nous fûmes!
I am an electrical engineer and work out of Milwaukee with a consulting firm and I do handle this grid intertie inverter issue a few times a year from our clients. I want to grid-intertie with a small wind for all the good reasons people do these things. Unfortunately, I have noticed that the prices for a grid intertie LISTED inverter is usually much more than a basic inverter. In order to shave your load, it needs to be UL 508 (for motors) and UL 1741 (for grid-intertie) listed. Older style were just 508 listed for wind generators/controls. A UL 1741 is usually the minimum a utility will accept. Believe it or not, most utilities that I've dealt with have incentive programs to help defray these costs because they are under pressure to DELAY building new power plants and so funding is available, you just have to start local and work outward to the state level and do some homework.
Usually the poles in a car alternator have enough residual magnetism to self-excite and once the alternator is generating power it will be difficult to determine if the field current is from the grid or from the alternator.
Apocalypse Cancelled, Sorry, No Ticket Refunds
Power distribution is not simplistic at all. It is a huge balancing act between supply, demand, and current/voltage phasing.
In a net loss condition, the inverter system should drop off line. This prevents the isolated island syndrome and I doubt that most home equipment generators can supply enough energy to run more than one/two homes before overloading.
Power quality is paramount to all and affects all. The standards exist to ensure that. This means that the generation equipment has to be able to adjust its output voltage so that there is a net flow out into the grid and at the present power factor presented on the line. Ideally, the power factor should be 1.0 (current/voltage in phase) but that is rarely the case. So, the equiment has to be able to adjust its generation to match the line conditions. That is not an easy thing to accomplish and I can probably say with a good amount of certainty that hobbyist equipment out there can't perform the necessary task of offsetting the voltage/current phasing properly and adequately. Therefore, the power companies are within their right to prevent an inferior power generating source from being hooked up to the power lines. Personally, I don't think that there is ENOUGH regulation in place to limit the garbage impressed back onto the power lines from attached equipment.
The cost of the equipment is high because of the complexity of its task, both in generation of smooth, clean waveforms and to be able to protect itself at the same time. Let's take, for example, a large wind turbine, say 2 megawatts. The power that is going out to the power line is sine wave power from a rotating alternator. It is the control equipments responsibility to ensure proper operation. A home operation will probably use a PWM converter and huge filter that will provide a clean sine wave. You still have the same control issues that the wind turbine has with the home unit and its associated costs. But here, economy of scale really plays in here.
From having to track down noise sources on power lines because of the interference they create to other sources has really created an appreciation for clean power usage and generation. The cost point of ensuring a PWM power generation system on a small scale provides clean sine wave is just too prohibitive for the average hobbyist.
Then there is the payback on investment. Wind and solar generation are not on all the time. That is a given that you can't avoid. So the ROI gets stretched out.
This can be done, but at what cost to ensure good, clean usable power that meets the necessary power standards?
I would also think long and hard about criminal liability for the death or injury to utility workers who get killed
How about a thought or two on the ethics of adding serious risks to someone else's job without them even knowing so that you can save $1,500?
I'd say, if it's a hobby, then create some isolated systems in the house, power an A/C or computer off self-generated power. That's a hobby. Tying into the grid is a home upgrade that ought to require a professional's license.
I hear you but here, in France, you can't even use your own electricity. By law, you're obliged to sell it to the electricity company which, in return, is required to buy it at a pretty high price. I heard some people make big bucks out of this.
I'm a college student with a small solar power system in my dorm room which is independent of the grid. I installed the solar panel outside my window, run the power to batteries, and run my computer and lights off a camping-style inverter I got used. The cost of everything except the panel was less than $100. I still have dorm-supplied outlets I use when the batteries run out.
I think the key here is simply to isolate your hobbyist power from your grid power. It's easier and less dangerous for everyone involved.
(I didn't read through all the comments, sorry if this is a repetition.)
We simply have to start cleaning up our act and go along with EU, Australia, and Canada on enacting a carbon tax on all goods (and EU will be doing it to prevent manufacturing from leaving there). I seriously doubt that the UN will fight it.
I prefer the "u" in honour as it seems to be missing these days.
> Power goes down, circuit opens.
Except... the power doesn't go down, because you are back-feeding.
Go to the deer hunting section of Walmart, Gander Mountain, Academy etc. They have solar power deer feeders for under $100 complete. Panel, charger, circuitry, battery, motor and a timer. You can get them cheaper at closeout Dec-Jan.
Exactly. I have a car that is doing this right now...the field wire has a problem (not worth discussing now - stupid old sports cars) and I have to get to 3k RPM to auto-excite the alternator. After that, it still produces power at idle with no problem. I what would make more sense for an off-the-shelf unit would be an automatic transfer switch. Yeah..they're expensive, but you just leave the "generator" side open, feed your renewable power source inside your house PAST the ATS, and when the grid power goes down it will isolate your house.
Do not fold, spindle or mutilate.
This has to be one of the dumbest statements I have read here in years! What, exactly, is the lineman to do if the line that is down, broken, laying on the ground, shut off at the substation, is still being powered by some yahoo's home-brew system??? Ground it??? How exactly does that help him repair it???
Not to mention the whole: oh look, electric wires down and laying on the ground, how exactly do you approach them safely? Well, I'm sure that first you go through a process to confirm that they have been indeed been shut off. And again, if some yahoo's home system is still powering them, how exactly do you propose that a lineman approach them safely???
Wow, "he grounds live wires to ground". You really have no idea what you are talking about. I AM A LINEMAN. Do you know what happens if you are on a 50 to 90 foot pole in the middle of the night in a storm and you put grounds on a 21,000 volt line? You will be engulfed in a fireball and airlifted to the hospital. The cost of the equipment is in its promise that it will almost always work. The cost comes from the testing and built in redundancy. Before you suggest someone cut corners ask a lineman to show you his injuries. Any lineman, at random. If I ever see anyone put some junk up like some people suggest here and put my life at risk, we will cut your power so quick it will make your head spin. Look at the history of linemen and you will see why things are done like they are now.
Don't feed back power to the grid. I would be very surprised if you generated more power then you can store in batteries.
At one point I did alot of research on solar power, its only feasible if:
1) the solar panels are free
2) there is no other power available
Solar panels will take approx 20 yrs to pay off. The wind turbines generate far more electricity then you will ever get from solar.
Solar windows and solar water heaters can help cut a few costs.
"A home's value is increased by $20,000 for every $1000 reduction in annual operating costs from energy efficiency." -Appraisal Journal, 1998
This is inaccurate in the US.
In many cases, small projects don't require a permit at all, when done by the homeowner. There is no universal requirement that a permit be obtained.
And even if there is a "legal" requirement for certified equipment, permits, and such things, there is certainly no technical requirement for them, and if you can put in your own grid-tie system safely, without the authorities noticing anything, there is no real reason not to.
If you aren't generating enough power to justify the $2000 inverter, you probably won't drop your utility bill enough to make it worth the effort. As others have suggested, just go for point solutions, like solar-powered patio lights and the like. Of course, that will be horrendously inefficient...
tying into the grid is nice, if you're going to be producing enough power to light up 5 homes with an insanely large wind turbine, but this guy was talking about a hobbyist sized deal, where he's gone wrong is thinking he needs to tie in the grid at all. Batteries, cheap lead acid car batteries, they're really easy and cheap, and for a small project you might only need one $25 dollar battery and some cheap electronics that are quality but not certified for tying in the grid... then you can run a few lamps, maybe a refrigerator, maybe a tv, maybe even a computer... if you can predict the amount of energy produced all day, and the amount consumed, you can design the setup so the battery never dies, and always stays charged up...
why tie into the grid, when you're only producing enough wattage to power a single light bulb? eg: a home made windmill with a used car alternator.
why would you even consider tying into the grid instead of using a recyclable efficient lead acid battery?
as an example a nice DIY windmill might cost you $200 for a 16' pole, $30 for a used alternator, and $10-20 for wood and screws, and $40 for a new lead acid battery, plus $20-40 for wiring and electronics parts all told a DIY windmill for under $350 again it will probably only run a couple lamps, but the whole project is DIY
why tie into the grid when they sell lead acid batteries so cheap?
https://www.gnu.org/philosophy/free-sw.html
I'm not interested in a single purpose machine. I want to generate electricity and use that to power my blender, computer, DVD, whatever. However, the flywheel design is exactly what I'm looking for. Maybe it wouldn't be too hard to put a generator on the blender mount.
"What does sound like a hobbyist project to me, is building a homebrew windmill, using it to charge a UPS, and using that to power, say your low-voltage garden lighting, and your garage lighting."
I realize the UPS has a lot of the requires circuitry, and it can charge the battery up, or let the current through, or do both... but usually UPSes have Maintenance free batteries. i like good old maintainable lead acids, that you top off once a month to deal with evaporation or electrolysis to hydrogen gas.. there is no way for the hydrogen to build up if the battery isn't enclosed, and thus no way for it to explode.
that means doing more of the wiring on your own, or at least buying kits off the net, but still it's SAFER, even if you have the UPS in the garage away from flammables it's not pretty trying to clean up an exploded UPS.
plus it's harder to recycle/replace the battery and batteries and electronics SHOULD NEVER GO IN A LANDFILL (even though most do)
making a home brew windmill is definitely a cool weekend project and it would be pointless to put 4x the cost of the total home brew project just to tie in a small.
https://www.gnu.org/philosophy/free-sw.html
I am a CET!
So am I.. Are you an apprentice? Google search a reverse current relay. When measuring the phase of the current and voltage forward power is voltage and current in phase up to 90 degrees out of phase depending on power factor. Beyond 90 degrees toward 180 degrees, you are in a reverse current mode feeding power to the source. In a grid tie system, this is normal as you intend to sell power. The industry norm (including driven inducton motors) is to lag the phase. Upon loss of grid, including islanding, the voltage collapses, or you run at a rapidly receeding phase (low frequency) where you relay out for out of tolerance frequency or voltage or both.
They make controllers which monitor the frequency, current and phase just for this application.
Purchase a copy of IEEE Std 1547. It lists the co-gen requirements.
"Cummins peddles cogeneration switchgear for use with their generators and these are based on Basler's cogeneration relay which combines the protective functions that you need. These packages allow you to do both manual and automatic synchronising. Your utility might want to review the schematic diagram and relay features for these cogeneration packages but they are pretty cut and dried. Alledgedly, Basler's relay is smart enough to know when a line is deenergized from the other end when an arcing fault occurs so that the Basler relay will also trip out.
Similarly, inverters for interactive solar generation include a relay that disconnects from the line when there is a power failure and can sense when 1 or more inverters are the sole source of power. Some of this is done with voltage sensing and some of this is done with impedance sensing. That is, the line impedance that a solar inverter sees changes dramatically when the utility opens its circuit breaker or fuse."
From;
http://www.eng-tips.com/viewthread.cfm?qid=145806&page=1
The truth shall set you free!
Pulse width modulation produces a rectangular wave. If the duty cycle is 50% then that rectangle is a square.
I see even classic Slashdot is now pretty much unusable on dial up anymore.
It's not pretty (given that alternators want to output three-phase) but it looks possible. I don't think it's a great idea, just tempting because junk alternators are cheap.
It would be really ugly. Learn something about junk alternators. I think you might be speaking a cheap home 60 HZ machine. Most of these are really single phase 120/240 (US market) unless you are speaking of a car alternator which is 3 phase, but it is far from 60 hz for effeciency in size and weight.
First to make it really ugly, the home generator has laminated core on the AC side to reduce the eddy current losses in the core. The Field on the other hand often does not have laminations so eddy currents can provide regulation stability and react to dampen AC current spikes and other transients that would otherwise cause damaging voltage spikes in the field current. The field is often would with some shorted turns so it can sync as an induction motor and pull into sync as a syncronous motor. Putting AC into this Field winding is often impossible as many AC alternators to eliminate wear items are pilot excited to eliminate the brushes. A fixed field on a small pilot alternator provides AC to diodes which then power the main rotating field in the main alternator.
If you are speaking of car alternators, again the field is DC. Most have slip rings to power the rotating field. These instead of having 2 poles on the field, they often have a set of fingers so there is often 14 or more poles. This drives a 3 phase winding which is then rectified into DC. Due to the number of poles and the number of cycles per revolution, you can't just cut the diodes out and expect to obtain anywhere 60 HZ unless you drive it really slow (just over 514 RPM for the 14 pole machine) and get really low voltage and low power as a result. Driving the field with AC won't produce an AC output after the rectifiers. An alternator produces AC with a DC field current until rectified by diodes. (Yes a car alternator does produce AC current in it's windings.)
http://www.alternatorparts.com/understanding_alternators.htm
The truth shall set you free!
Utility companies have this power thing locked up and are going to be very reluctant to let small producers get in the game. Utility companies should not fear small producers they should embrace them and buy their excess power and resell it at a profit without any over head. The largest source of funds to build the power supply sytem is in the pockets of consumers: let consumers build it.
Most consumers do not have the capacity to meet their own usage, let alone sell any. Many small systems are in the neighborhood of 5-15 KWH/day and a typical family residence is in the 25-40 KWH/day. Either severe effeciency measures are needed, and/or more capacity is needed.
Look at last month's bill. What was your daily KWH usage?
The truth shall set you free!
I don't think anybody looks at the advantages of energy consumption when looking at corded/cordless drills, but rather the convenience
College-Pages.com - Online Colleges, Degrees, and Programs
" Solar panels cost about $4-5/Watt, inverters cost $1-2/watt."
That's cheap for solar panels. But it's way high for inverters. I paid $0.11/W for mine, decent ones, retail, with big guarentees.
Need Mercedes parts ?
" If the duty cycle is 50% then that rectangle is a square. "
Yeah. Try running a microwave from a cheap generator. The clock runs 10X too fast and it never heats up.
I'm a computer programmwer not a power engineer. I make things red or blue on the screen or bold or italic and don't know power factor from Max Factor but I'm guessing non-sinusoidal output here.
Need Mercedes parts ?
" Sure. You anywhere in the midwest?
I could^H^H^H^H^Hwill be if that's what it takes.
Need Mercedes parts ?
"i> For example, I used to run the vent fan on my greenhouse based on solar power. When the sun went down or when it was cloudy (i.e., when you didn't want the fan running), it'd stop"
Put 4 mirrors around it to concentrate the sunlight. I have a solar AA battery charger that only works on days, but by using one big mirror I can jack the output 3x (as measured) and it works on cloudy days now. This also boosts the output of my big solar panels, which just got dedployed. Currentlyu I'm on a hunt for a lot of mirrors. Like, 50 of them.
Need Mercedes parts ?
" Batteries need charge-controllers"
Let me correct that for you. *small* batteries need charge controllers. The smallest industrial Exide battery
(800 Ahr 1500 lbs) doesn't need one for anything your gonna throw at it with consumer grade solar panels and
wind turbines.
But no, you don't want to overcharge small batteries. Charge controllers are pretty stupid cheap though frankly,
and most wind wurbines have them built in to boot.
Need Mercedes parts ?
I can probably fabricate a circuit with an oscillator that syncs up to the 60Hz of power. After that, it's a matter of how to convert from DC to AC. It doesn't seem hard to me. Not hard, perhaps, but not legal; for some very good reasons. There is a long established protocol for attaching to the public power grid. It addresses disconnects for emergency workers, such as firefighters, and service requirements for those who service the grid.
In simple terms, it's irresponsible to encourage people to monkey around with something which could have devastating and even deadly consequences for others. Check out the rules and understand their purpose before subverting them.
Well put. Well said . True by any reasonable measure.
I would wager that those making the ill-considered argument that it's all a con know little about the technology or responsibility for shared utilities or public policy.
Thank you!
The hotter you run panels, the less efficient they are, and the faster they degrade. Just so you know.
"99 dead duelists of Dios on the wall. 99 dead duelists of Dios! Take one's ring, pass it around..."
PWM is about modulation of a square wave (achieved by comparing a triangular wave with a pure sine wave using a comparator). If modulated just right i.e. if the modulation index is optimal, using the leakage reactance of the output transformer, the HF square wave is easily filtered off leaving a pure sine output!(99% pure sine with a conversion efficiency of about 95% at optimal load) Simple concept isn't it? Actually not :) To add to this complexity is the fact that the input to the modulator needs to be in synch with the mains! This should explain the cost of $2K upward.
I see the mention of brushless motor here. Spoils the game you see.... moving electricals are notorious for their pathetically low efficiency. How low? Well a bad bad 30%!! So compared to a PWM system you may end up using 4 times the number of solar cells to get the same power.
Hook your solar/wind/mini-hydro setup to car batteries, hook those up to some 12v DC outlets and use car chargers to run your laptop, cell phone, and some LEDs. Add a small voltage regulator next to the batteries and run lines with USB plugs on them for 5v DC and run/charge everything else.
For the same reasons, I added a solar panel from Harbout Freight APX. $200.00, plus 4 battries APX. $200. DC to AC inverter APX. $50.00. I did take just one of my AC cirtuits from the main electric panel and fed it from the AC invertor. I have Kitchen, dining room and the back porch lights only on that circuit, and that seems to be working fine. However I did change all mu bulbs to low power 23 Watt bulbs. All togather I have 4 light switches with 15 bulbs. This seems to be woking fine. I did need to downsize my AC invertor, originally I installed a 1500 Watt invertor. I found that this invertor was using too much power just to run it, and I was wasting power just for the invertor, inother words the unit was oversized for the amount of power I needed. Now I have a 700 WATT DC to AC invertor and that seems to be working must better. BTW, this one circuit is totally fed from the SOLAR and rest of the circuits are still fed from the grid. I do plan to install some more solar panels and will cut over one circuit at a time. Bild my solar input little at a time. I have a cut over citcuit ready but have not installed it yet. This circuit, using inexpensive simple over the counter parts will allow me to switch back to the grid if my batteries run too low, for example no sun for long time. I have not run into this yet.
Ok, so not exactly hobbyist, but would be neat to have. A Toshibiba Micro Nuclear Reactor.
http://www.nextenergynews.com/news1/next-energy-news-toshiba-micro-nuclear-12.17b.html
FTA:
-20x6 feet in size
-200Kw
-Failsafe, totally automatic.
-lasts up to 40 years
-produces energy at 5 cents per KW/H
I knew a guy years ago that had a junction box in between his power box and the grid. It just had two circuit breakers, one inverted to the other, the switches taped together. Push up, you're on local power. Push down, you're on grid. It passed city inspection. Obviously, it may not pass yours.
One method is to use a regular AC induction motor driven by the grid. Unloaded this will run at slightly less than it's rated speed. The more power you take out of it, the more farther behind sync it slips. The reverse also applies, if you drive it faster than it's rated speed it will start to slip the other direction, pushing power into the grid.
Obviously just driving the motor without the grid doesn't produce any electrical power. So, when the grid goes down, your motor no longer produces any output. That is, presuming that your neighbors aren't trying to pull the same trick.
The grid supplies VARs to the motor to make it work. Of course the utility company has to make sure that sufficient VARs are available, as I understand it this usually involves installing big-ass capacitors on the line. The VARs consumed by the motor count toward it's rated power, so you can't push a full kW out of a 1kW motor, some of that capacity will be taken by the VARs.
You'd still have to provide a mechanism to disconnect from the grid during power outages or you'd be pushing your power out into the other nearby houses, but such a system might work more cheaply than an inverter system.
And, to address the original article, the home hobbyist can approach the system by selecting (or tailoring) specific circuits to completely disconnect from the grid and power from a renewable energy system. For example, if you have a 50W solar panel, consider installing a system that can run lights that consume 200Wh per day, perhaps the bathroom lights. This avoids the cost and complexity of grid-tie and also helps build awareness of the hard limits of the system (whereas grid-tied systems have infinite capacity, an independent system will cut you off once you've reached the limit, a good self-imposed reminder that you could probably conserve more than you are).