Scientific American: Today, renewable energy sources generate 12 percent of electricity in the U.S. But wind, wave, sunshine and others represent more than 93 percent of the energy the country could be producing, according to the Energy Information Administration of the U.S. Department of Energy. If renewable energy is going to be a bigger player and have a significant impact in cutting the greenhouse gas emissions from power plants that are driving climate change, it’s going to have to grow quickly. …