New York Times: Key senators are studying whether power plants should be the guinea pig industry for the nation’s first cap-and-trade system designed to curb greenhouse gas emissions. Electric utilities are responsible for about a third of the country’s annual heat-trapping pollutants, and they have been involved for about 15 years in a similar market-based mechanism that has successfully reduced acid rain. But the focus on just one industry also comes with perils, and it is far from certain …