The document discusses various sources of energy, including wind power from wind turbines which can cost $22,000 but are renewable and produce no greenhouse gases; solar power from solar panels which can cost $30,000 but are also renewable and clean; fossil fuels like coal, petroleum and natural gas which are non-renewable and formed over 300 million years ago; fission which can be dangerous but is stored in fuel cells; hydropower from moving water which costs $2,000 per kilowatt but is renewable and clean; biomass from stored plant energy which costs nothing if using compost; and geothermal energy from the earth like hot springs which requires a $34,000 system to capture the stored underground