DIY electricity

The Dallas Observer published a report1 recently that Texas has worst electric grid in the nation. This was based on a North American Electric Reliability Corp report2. That’s not very encouraging. They are also reporting that there is the possibility of rolling blackouts in 2013.

For a couple of years I have had the interest in setting up a backup power system for home use. There is a mobile system that provides power for work a couple of times per month, and is a backup system when at home. It provided power for 2 freezers, a refrigerator and a fan during 3 days of outage one summer several years ago. But we really want a system that has the specific purpose of supporting the house.

When looking for a mobile 120 volt (V) system I did talk to an “expert” who wanted to sell the best system that they had. He wanted to get me excited about selling power back to the electric company. After redirecting the talk with the expert to a mobile plan, and taking some of his advice, it proved to be an exercise in frustration.

Here's the money quote from that particular manufacturer:

When you compare the costs of solar and our thermoelectric generators based on the amount of electricity they actually produce per day, you find that our TEGs cost far less per kWh than solar. The PV (photovoltaic) equivalent of 50 watts of TEG power operating on a wood stove is 330 watts of solar panels or 1.2 kWh per day. This means using just 150 watts thermoelectric power can produce the same amount of electricity in a day as 990 watts of solar PV panels. If comparing costs, the price range for 990 watts of solar would be as much as $5,000 depending on the particular brand. Whereas the cost of 150 watts of thermoelectric power can be as low as $500. Unlike solar TEGs are not dependent on the sun to producing electric power. If you have a continuous heat source, like a wood stove, TEGs can produce power day and night, 24/7-365. Granted you will need a cheap or free source of heat, but if you already have an existing heat source such as a wood stove or hot flu gases there is no added fuel cost to run the TEG. Unlike conventional electric generators powered by fossil fuels, TEGs have no moving parts to break. They are virtually silent and rated to last more than 200,000 hours of continuous operation.

They're marketing individual units in a sort of DIY approach, and like most others push the "green" aspect. I don't give a hoot about symbolism, I'm looking for practical, affordable sources of powering a home in the absence of grid power. The excerpt above is one of the few examples on that particular site mentioning woodstoves.

I'd have to do some looking around to validate the cost comparison but if accurate, it's 1/10 the cost of solar, far less prone to failure and can be powered by any source of waste heat. Max temp and min temp to generate electricity would matter when designing an array, a "thermopile."

I'd think, given the presumed cost advantage, that a simple parabolic setup along the lines of that solar stove would work in sunny warm weather, and a woodstove or even hot water heater would work in cold. Whether an array could be designed for portability or not, for different applications given current circumstance, would be a good question to investigate.

I expect to see a lot more of these things popping up on the market in finished consumer goods. Camping is the obvious place and it's already out there in the Biolite camp stove with thermoelectric charged USB port.

It gets especially interesting to me when pondering the possibilities of being scaled up for emergency residential use, though.

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