Wind Power Number of the Day: 59.3%

59.3% -- Albert Betz calculated in the early 20th century that the maximum theoretical efficiency of a wind turbine is 59.3%.

50% -- Currently, modern wind turbines are efficient at about 50%, a very impressive number.

15% -- According to GE, when it entered the wind turbine market in 2002, the average wind turbine was out of commission about 15% of the time.

3% -- Nowadays, wind turbines are down only about 3% of the time. That helps drive the cost of wind power down and get the most out of each turbine. Uptimes can probably be improved even further.

8 -- Electricity produced by a m...