onshore wind farms
Ed Miliband said it was part of plans to turn the UK into a "clean energy superpower".
The prime minister's U-turn comes after a rebellion by Tory MPs.
Her jibe came after the PM performed two humiliating climbdowns in 24 hours.
The shadow climate change secretary accused Conservative "dinosaurs" of being opposed to clean energy.
The prime minister pledged to oppose any new developments when he was running to be Tory leader.
Boris Johnson said it will provide "clean, affordable, secure power" for generations to come.
Transport secretary Grant Shapps said they were "an eyesore" and damaged the environment.