Besides solar cells, the other big renewable energy form is wind. While you can buy 500W turbines to put up in your yard, the real money is in the big systems. But big is a moving target. Once apon a time a 50kW unit was big, then came the 200kW, then the 600kW, then the 1.5MW. These things were getting pretty darn big. Well now big is 5MW, like the new unit in testing from REPower.
Construction started in April, and they hope to finish by the end of the year (putting together a 200 ton windmill is not a quick job). The unit features a 390 foot tall tower, and required quite a tall crane to lift the 120 ton carbon fiber composite rotor on to the top list last month. Each rotor is over 200 feet long:
To make it easier to get to the main housing for maintenance, a helicopter pad was included in the design. Hope those spinning rotors don't interfere with the airflow too much. Not the kind of house call I'd want to be making on a regular basis.
At a price of $17MM, this works out about the same price as solar panels, though obviously wind is more available in some locations (such as offshore) than the sun. Still with the estimated annual output of 17GWh per year, this is only expected to meet the need of about 4,500 people in the nearby German town. Using these to meet the needs of millions would require thousands of towers and billions of dollars. And lets not even bother with the math for a country like India or China that has billions of people. Thinking about power and construction on that kind of scale is just mind boggling.
[references]
Articles from Renewable Energy and
Reuters.
