From the press release: > More than 90 percent of the world’s electricity comes from sources of heat such as coal, natural gas, nuclear energy, and concentrate

From the press release: > More than 90 percent of the world’s electricity comes from sources of heat such as coal, natural gas, nuclear energy, and concentrated solar energy. For a century, steam turbines have been the industrial standard for converting such heat sources into electricity. > On average, steam turbines reliably convert about 35 percent of a heat source into electricity, with about 60 percent representing the highest efficiency of any heat engine to date.