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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?"
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. "
Yes.
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)
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.
This is a common mistake and is only good for very low power stuff. In picking a wire size people often think going from 120 volts to 12 volts only involves the math of supplying a wire 10X larger to handle the current without overheating. In a 120 volt application, you are permitted a 5% voltage drop. This isn't much as 5% of 120 volts is only about 6 volts. No big deal when running a 1200 watt portable hair dryer. If you simply size the wire to now do the same thing on 12 volts, you no longer have a 5% voltage drop. At the same current you still have a 6 volt drop with the 10X larger wire but you now lost 50% of your power in the wire. Take a hint from the pro.. Use an inverter. The 10% the inverter lost is made up by the 45% not lost in the wire. Do the math. Engineer the project.
Either your high draw items (Microwave, toaster, blender, etc) are either within 20 inches of the battery, or you will want an inverter. With an inverter you can use standard appliances. Look for energy effecient ones.
Another item is to ditch the grid tie for small systems. It goes down with the grid providing no security. Put the critical load on an Outback inverter. It was made just for this application. Small solar, battery maitenance, load transfer to and from solar and battery, etc. You don't have a surplus to sell to the utility, so don't connect that way. Use it to supplimant your load and reduce your total load. As a bonus, you don't have to enter a grid tie agreement with the utility where they buy your power whosale and sell it back to you retail.
Find Outback stuff here;
http://www.outbackpower.com/
Disclaimer, I just use it. I am not otherwise involved with this company. The company has grid-tie stuff if you decide you really want it. I don't recommend it except for larger installations. This company has done a great job meeting the market. Their grid tie units are the first that I know of that operate instead of shutting down in the event of a blackout. They solved the number 1 problem with grid tie stuff.. blackouts.
http://www.partsonsale.com/outbackgridtie.html
The truth shall set you free!
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.
Your problem is you use too much power. I had the same problem and just unplugged or rplaced everything that was overconsumptive. 700W desktop tower goes away in favouir of 45W laptop. Cordless drill that takes hours to recharge is replaced by a fast charginbh lithium ionh one. etc.
I cut my power to 1/4 doing this. THEN went solar. Your 30K cost is now 7K.
The OP doesbn't need a grid tie invertor. That's for selling excess power back to the power company.
I run a sat receiver by having it plugged into a ups with a ubiquitous 7Ah SLA battery, fully charged, with two 30W solar panels hooked up directly to the battery. It just sits there and works.
I have lots of solar panels, i just hook them up in lotrs of little autonomous systems than do one thing. Free, and forver (or until some part beaks or the sun stop shining).
I've got a bunch of these setups for various things with various batteries and inverters.
I can't for the life of my see how "small scale" and "grid tie" relate at all.
If you had an 18Kw hydro plant I could see it but...
Need Mercedes parts ?
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.
unfortunatly I am a software developer, so I tend to resist all forms of documentation. Here is my rundown (the setup of my house means I didn't even run any wires through the house so this was so freaking simple:
Wall unit AC (was what we used before the conversion) is on the back wall of the house) 115v 10,000 BTU unit I think they retail for ~$400-$500 (but we already had it)
My solar panels were second hand, so they were cheap, they were operating at ~81% their original capacity, so the company sold them to me for less than 1$/watt I have about 1300 watts, and the AC when it is on (it switches off and on throughout the day) it uses up to 875 watts. I got very lucky on the price for the panels, and the additional wiring and stuff, so maybe my $1000 number was not very "honest" maybe double or triple that if you are buying with urgency instead of waiting for a killer deal like I did. The capacitors I use are a cluster of those 2000 Farad Car stereo ones (I know I know it is not the right thing to do but it is the cheap thing to do, and they are firewalled). They are before the inverter, to feed it continuous power. And seriously that is about it, I mean wiring solar panels is about like wiring batteries (parallel banks of your desired series of voltage), then do the same with the capacitors, then the inverter, which can be bought for cheap from a Truck Supply store (some bigrigs use them, to run things like 1000 watt Routers, jackhammers, etc) From there, my inverter is mounted on my back porch (near the A/C unit) and the A/C is plugged directly into that (it has A/C outlets in it).
The roof vents are just seperate left over panels, with DC fans that run directly wired to the panels.
So basically I bought cheap ass panels, some consumer electronics, and put it all on my roof/porch. Doesn't sound as glorious when I put it that way, but in all I have almost made my money back in energy savings as compared to the bills from last year... and that is significant for me since I really only did it for fun. I think I will be in the black in August of this year, and the gear is still going strong, so hopefully it will be an actual cost savings.
The purpose of the grid tie isn't to provide security or to support a critical load. The purpose of a grid tie is to prevent the home power system from powering the grid when the grid goes down - if you pump power into the grid when it's down, you risk the health and life of workers trying to restore the grid.
For example - A line went down that supplies my road. Before workers started repairing the line, they isolated it at the substation, rendering it safe. Without a grid tie the line remains powered from the home systems - which can kill.
If you have a critical load, put it on a UPS. Don't skip the grid tie unless your home system is entirely isolated from the grid.
Seriously, there's times to home brew and jury rig and save a few bucks, this isn't one of them. Do it right and don't put lives and property at risk.
A company called Solatube makes pre-made solar powered attic fans
One of our competitors trademarked the term "hypothesis". From now on, we will call them "boneheaded ideas".
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.