Tuesday, July 28, 2009

Wind Economics - First Step

When I bought this house last year, I was really excited about the possibility of using a wind turbine for power. Before I even got my first electric bill, I had asked my town if it was OK for me to put up a tower. (They said that there's nothing in the regs preventing it, so go right ahead. They checked county and state regs too, for height restrictions. The results escape me now, since I had done some preliminary economic calculations by then.)

One of the first steps, even for people on mountains, is to determine how much wind is available. I bought a wireless weather center last fall, but stopped short of using it because I couldn't figure out how to mount the anemometer in a way that I could access it to change the batteries when necessary. On Sunday, I finally overcame the lengthy inertia, bought some galvanized piping and mounting pieces, and got the thing up yesterday (one of the rare times I've actually accomplished anything on a weeknight). This one is at 20 feet, which is technically too low to get a true reading of the wind (note the trees about 40 feet SE of the thing). But it would err on the low side, meaning if it's acceptable at this altitude, it would be great at 60 feet or higher. PS, I suspect I should ground it before too long...

(Warning, geeky engineering stuff follows.)
On the economic side, my stove and water heater are run by propane. My furnace is heating oil, and the rest is electric. My average electric use last year was 12-24 kwh per day, about 4300 kwh for the year (at a delivered cost of 11.6 cents per kwh, I spent about $500). If I converted the propane stuff to electric, it would about double this number. (I am aware of, but didn't take into account potential savings because my current water heater is old and inefficient.) The potential savings then is about $1000 per year at best, ignoring the heating oil usage. I estimate that I'll use about 300 gallons of heating oil (which is half what I used last winter - I learned a lot about that!). The kwh equivalent of that is 11,757 kwh, which in oil will cost me about $800.

In summary, a turbine to take care of my electricity only would deliver 4300 annual kwh. Adding propane, the turbine would deliver about 9,000 annual kwh. Adding heating oil would size the turbine to deliver 21,000 kwh a year. Installed cost for a turbine would run somewhere in the vicinity of $20,000, just to cover my electric use only! To cover all my uses, it would be north of $100,000. It's easy to see that there is no economic benefit to wind power.

That is, there is no economic benefit now, with my inefficient lifestyle, and wide open, windy house. When I make the house more air-tight, and get better at being efficient, I'll do the calculations again. It's likely that I would require a smaller size blade, and also likely that the technology will advance a bit and may be cheaper then. By then I'll have data on the available wind here too.

There is definitely a benefit to being off-grid though! So I'll keep at this thing and maybe the benefits will tip the scale over to the plus side in a few years.

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