The pattern of wind power’s tax credit dependency is clear: In 1999, with the PTC in place, 575 megawatts worth of wind power was added to the nation’s grid. The credit was allowed to expire in 2000, and just 43 megawatts worth of wind projects were built. The credits were restored in 2001, and 1,696 megawatts of wind capacity went online, followed by just 410 megawatts of new wind power in 2002, when the credits were allowed to expire. The credits have remained in place since 2005, leading to the addition of 2,431 wind-generated megawatts that year, 2,454 in 2006 and 5,244 last year