WRAPUP 3-Britain to double low carbon power role by 2020

* Britain unveils route map to low carbon economy

* More than 400,000 new UK 'green' jobs expected by 2015

(Adds context of EU partners' goals)

By Peter Griffiths and Nina Chestney

LONDON, July 15 (Reuters) - Britain will double the share of its electricity generated from low carbon sources by 2020 as part of plans to cut emissions and counter global warming, the government said on Wednesday.

Energy and Climate Change Secretary Ed Miliband said 40 percent of Britain's electricity will come from nuclear, wind, solar, marine and cleaner coal, compared with a fifth today.

By 2020, renewable energy sources will provide 31 percent of Britain's electricity, up from 6 percent today, while nuclear's share will fall to 8 percent from current levels of between 15 percent and nearly a quarter, depending on the variable output of nuclear plants.

"Our plan will strengthen our energy security...it seizes industrial opportunity and it rises to the moral challenge of climate change," Miliband said in a statement.