The Wall Street Journal cited a paper that appeared last winter in the Journal of Economic Perspectives in a column about the low probability that electric cars would replace gas-powered vehicles anytime soon. The JEP paper by Thomas Covert, Michael Greenstone, and Christopher Knittel concluded that, without major greenhouse gas policies, the global economy was unlikely to stop relying on fossil fuels as their primary energy source. Despite substantial progress in reducing costs of “clean” technologies, the authors say those energy sources were still too expensive to compete with relatively cheap and abundant supplies of fossil fuels.