But Nakamura and colleagues are betting that Japan’s new pricing system, which guarantees a premium price for every kilowatt-hour of renewable energy exported to the grid, will cover the higher costs.

Investors could invest up to $37.5 billion by 2014, spurring 10 gigawatts of new solar—the energy equivalent of three nuclear power stations. That would make Japan the world’s third-largest solar market. Bloomberg projects 0.7 gigawatts of new wind by 2014, but says growth should pick up thereafter.

The Japanese government is also funding development of novel options for renewable energy. Those include floating offshore turbines adapted to Japan’s deep coastal waters. Marubeni and Tokyo University are leading an industrial consortium funded by the Ministry of Economy, Trade, and Industry that plans to install three floating wind turbines totaling 16 megawatts in capacity some 20 to 40 kilometers offshore of Fukushima Prefecture, as well as the world’s first 66,000-volt floating power substation.

Power experts say that limited interconnections between utilities will become a challenge as renewable energy expands. The 10 utilities that control Japan’s grid have resisted such upgrades, which erode their effective monopoly over power generation in their regions. But DeWit see the utilities’ power weakening. “I haven’t felt this optimistic about Japan for years,” says DeWit.

Change can’t come fast enough. In the short term, Japan is actually moving in the opposite direction, substituting on carbon-heavy coal, oil, and gas. Utilities produced 40.5 percent more power from fossil fuel this winter than they did the previous winter. As a result, consumption of crude oil almost tripled, and natural gas use increased by 34 percent.