This week the National Grid in the United Kingdom reported that renewable sources of energy were generating more electricity than coal and gas for the first time. Power from wind, solar, hydro and wood pellet burning supplied 50.7 percent of British energy. A tenth of the U.K.’s power was coming from offshore wind farms—a newcomer on the energy scene whose costs have plummeted far faster than expected. The announcement comes as records for wind power are being set across Northern Europe.