Wind, solar and natural gas are cheaper electricity sources than coal-fired plants if climate change costs and health impacts are measured, a U.S. study found. The study authors, writing in the Journal of Environmental Studies, say the United States can cut carbon pollution from power plants in a cost-effective way by replacing coal-fired generation with cleaner options. Using official U.S. government estimates of health and environmental costs from burning fossil fuels, the researchers reported they\'ve determined it\'s cheaper to replace a typical existing coal-fired power plant with wind turbines than to keep the old plant running. \"Burning coal is a very costly way to make electricity. There are more efficient and sustainable ways to get power,\" study co-author Laurie Johnson, chief economist in the Climate and Clean Air Program at the Natural Resources Defense Council, said. \"We can reduce health and climate change costs while reducing the dangerous carbon pollution driving global warming.\" Power plants are the nation\'s single largest source of such pollution, accounting for 40 percent of the national carbon footprint, the study authors said. \"And yet, there are no federal limits on the amount of carbon pollution our power plants may release,\" Johnson said. \"That\'s wrong. It doesn\'t make sense. It\'s putting our future at risk. We limit the amount of mercury, arsenic, soot and other harmful pollution from these plants. It\'s time to cut this carbon pollution. \"Already, climate change is contributing to record heat waves, floods, drought, wildfires and severe storms.\" Such extreme weather caused more than $140 billion in damages in 2012, with much of that bill being paid by American taxpayers, an NRDC report said. \"These damages are only likely to increase if nothing is done to reduce carbon pollution,\" Johnson said.