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?"

Comments

Renewable energy comer in many forms

[Anonymous Coward]

What are other options for the hobbyist to play around with renewable energy, other than charging a cell phone?

Breed Whales, burn the oil.

go 12 volt

[Jailbrekr]

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.

Re:go 12 volt

[Technician]

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

My partial solar solution in my grid tied house

[netsavior]

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.

hot water solar

[andrew_d_allen]

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.

Re:Renewable fuel

[rs79]

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...

One teeny problem...

[Anonymous Coward]

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.

Re:Use a 'fan center' to isolate when grid power d

[ahfoo]

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