Reid Gardner Station in Moapa, Nevada, is a coal-fired power plant undergoing an $85 million overhaul to reduce its emissions under an agreement with state and federal environmental protection agencies.

Coal, crude oil, oil shale, tar sands and natural gas are part of America’s mineral wealth. Fossil fuels generate damaging greenhouse gases that can be reduced using new “clean” technologies. Federal, state and local governments are encouraging the use of more renewable energy sources: wind, solar, biomass, water and geothermal. (© AP Images)