Wind Power

The difference in wind speed between the house, and the top of our hill is pretty impressive. I have seen wind speeds by the back door that ranged from 0 to about 5 mph. With no measurable wind at the house, at the top of the hill I was getting a pretty consistent 8 mph, holding the anemometer as high above my head as I could. As you probably know, wind speed increases as you get higher above the ground. The next step is to build a weathervane driven rotating gadget to hold the anemometer fifteen feet in the air, so that I can get a more reliable reading.

Skystream Energy offers a wind generator intended for low wind speeds--and which as an inverter built in, so it produces a 240 VAC output instead of DC. According to the chart here, it starts producing power at 8 mph, although the amount is pretty small. (Of course, around here, we get at least an 8 mph wind 24 hours a day. Somewhere around 25 mph, it is producing 2.4 kilowatts. If we ended up averaging 15 mph (which I suspect isn't too far off for the top of our hill), that would be a bit better than half of monthly energy use.

Most wind generators (all wind generators?) have a maximum speed, with various mechanisms for shutting off the blade when the wind speed gets too high. A generator like the Skystream 3.7 gets no benefit from wind speeds above about 25 mph--while generators intended to take advantage of high speed (and therefore, high power) winds usually don't start turning until the wind is already moving pretty briskly. It makes me wonder if, in a place like this, where we have continual winds of 10-15 mph--and at least monthly, hour after hour of 40-60 mph winds--whether it might make sense to have both a generator intended for the light breezes, and one of the larger generators that can take advantage of the high wind conditions as well. The light wind generator would be turning 90% of the time, producing a low but steady current--and the other 10% of the time, the wind would be moving 50 mph, and producing prodiguous output.

At least so far, when I look at products like the Air-X and Whisper wind turbines at this website, they all seem intended for relatively low wind speeds.