Swedish government to build one of largest windfarms in Britain The £400m Pen y Cymoedd windfarm in south Wales will have a 25-year lifespan and contribute £45m to the local economy, Vattenfall said. With a total of 76 turbines creating 228 megawatts of power, the windfarm between Neath and Aberdare will be the biggest onshore project in England and Wales. Offshore and onshore wind is an important contributor to our energy mix. We have provided certainty early to onshore and offshore wind investors and now see significant investment decisions being made that will benefit the UK's economy for years to come. Meanwhile, contruction on Vattenfall's Clashindarroch windfarm in Aberdeenshire has already begun, and is expected to be completed in 2015. The Scottish site will boast 18 turbines producing 36.9 megawatts of power. Peter Smink, head of Vattenfall's Sustainanble Energy Projects unit, said: "The UK market for investing in onshore wind power is an attractive market for Vattenfall because the government has backed its development as a crucial part of its growth agenda."