Renewable energy jobs grew by 14% to 6.5 million employees worldwide in 2013, says the International Renewable Energy Agency. In decreasing order, the largest employers were China, Brazil and the United States. The solar panel industry, spurred by falling prices, employed 2.27 million workers, mostly in China.

Wave power has the potential to be a massive source of renewable energy, yet it lags behind solar and wind power. An analysis in Yale 360 Environment describes the multiple challenges — including the difficulty of designing a device to capture the energy of waves — that stymie efforts to generate electricity from the…