Economist: MOST people agree that carbon emissions from power stations are a significant cause of climate change. These days a fiercer argument is over what to do about it. Many governments are pumping money into renewable sources of electricity, such as wind turbines, solar farms, hydroelectric and geothermal plants. But countries with large amounts of renewable generation, such as Denmark and Germany, face the highest energy prices in the rich world. In Britain electricity from wind farms costs twice as much...