President Barack Obama ‘s proposed rule to curb carbon emissions from the nation’s power plants could raise costs and affect reliability in the U.S. electricity system, federal regulators told Congress. But the commissioners of the Federal Energy Regulatory Commission, the government agency charged with overseeing the electric grid and other parts of the nation’s energy infrastructure, also said at a House hearing that the government has a responsibility to act on climate change. As part of Mr. Obama’s climate agenda, the Environmental Protection Agency is proposing to cut carbon emissions from the electricity sector by 30% by 2030 based on emissions levels in 2005. States are expected to comply with the rule by using cleaner, though potentially more expensive, energy. Utility companies are already shifting away from coal because of the natural-gas boom and other environmental regulations. The rule is expected to accelerate the trend, which could put pressure […]