Renewable energy - Blow hard

THE first wind farms sprouted in California in the early 1980s, thanks to generous tax credits. Today's machines typically have a capacity of 1.5-2.5 megawatts, or 30 to 50 times that of early turbines. Although wind generates only about 1% of all electricity globally, it provides a respectable portion in several European countries: 20% in Denmark, 10% in Spain and about 7% in Germany. Capacity in America jumped by 45% last year to reach nearly 17 gigawatts (GW). China has nearly doubled its capacity every year since 2004. Globally, wind power installations are expected to triple from 94GW at the end of 2007 to nearly 290GW in 2012, according to BTM Consult, a Danish market-research firm.