China looms large over the global climate summit in Copenhagen, where Chinese officials are pressing the U.S. and other rich nations to accept new curbs on their emissions and to continue to subsidize poor nations' efforts to adopt clean-energy technology. China is the world's biggest source of carbon emissions. Less understood is the way China is now becoming a source of some of the solutions.
China's vast market and economies of scale are bringing down the cost of solar and wind energy, as well as other environmentally friendly technologies such as electric car batteries. That could help address a major impediment to wide adoption of such technologies: They need heavy subsidies to be economical.