The document compares the life-cycle carbon dioxide emissions and costs of various power sources, including solar, coal, natural gas, coal with carbon capture, and natural gas with carbon capture. Solar has the lowest CO2 emissions at 40g/KWh, while coal is highest at 1000g/KWh. Coal and natural gas would produce 1.86 and 0.74 billion tons of CO2 respectively over 25 years at a capacity of 50,000MW, saving over 400,000 lives but requiring billions of trees to offset the carbon.