For the first time, residents of North Carolina will be able to buy their electricity from renewable sources such as wind, solar, and biomass. Under “NC Greenpower,” a new plan approved by the state earlier this week, industrial electricity customers can choose to pay about 2.5 extra cents per kilowatt hour for green power; residential consumers would pay roughly 4 cents extra. The plan was delayed by a dispute over whether discarded wood should be considered a renewable energy source. Opponents were reluctant to include timber products in a supposedly environmentally friendly energy measure, but advocates, who eventually won out, felt that the option was necessary to make renewable energy affordable for users.