Clean energy could become so cheap there’s no incentive to build any more. The plummeting cost of renewables could be a double-edged sword if energy markets fail to deliver the financial returns to justify further investments, experts believe. In the U.K., for example, a study by Cornwall Insight, an analyst firm, this month found that unsubsidized renewable energy projects could cease to be viable by the 2030s because solar and wind generation would have pushed wholesale pow

GIVEN THE WEATHER in the United Kingdom—that cloudy, foggy, drizzly country—it doesn’t seem like the best place to launch a business that revolves around solar power. But this is where the builder of the world’s best-selling electric car just started selling Nissan Energy Solar, a generation-to-acceleration scheme that equips customers with roof-mounted panels and a battery to store some of the electricity they generate. If they drive a Leaf, or Nissan’s e-NV200 electric van,

Long a leader and trendsetter in its clean-energy goals, California took a giant step on Wednesday, becoming the first state to require all new homes to have solar power. The new requirement, to take effect in two years, brings solar power into the mainstream in a way it has never been until now. It will add thousands of dollars to the cost of home when a shortage of affordable housing is one of California’s most pressing issues. That made the relative ease of its approval —

China is hoping to become the Detroit of the battery-powered electric-vehicle industry. Sales of EVs are expected to reach 1 million this year alone, and the government has big plans for expansion. But this welcome trend comes with a perplexing side effect: China is now using up more lithium-ion batteries than anywhere else in the world. What to do with them? Throwing those batteries away could be environmentally hazardous. Recycling them, meanwhile, turns out not to be very