Guardian: The world’s largest offshore windfarm, which cost over £750m to build, is poised to open off the coast of Kent, with 100 turbines producing enough electricity to supply heat and light for 200,000 homes. The Thanet facility, which is going through final testing by Vattenfall, its Swedish power company operator, arrives as the National Grid revealed that at one stage last week 10% of the UK’s electricity came from windfarms. But industry experts claim that the wider green …