Yale geology and geophysics professor Ron Smith surveys the world's major energy sources in this lecture from The Atmosphere, the Ocean and Environmental Change. He breaks down how energy is used for heating, transportation, and electricity generation, then moves resource by resource: coal's role in electricity production and its carbon dioxide and nitrous oxide emissions, oil and the concept of peak oil, natural gas extraction through hydraulic fracturing of shale, and nuclear power's stalled growth since the Three Mile Island and Chernobyl accidents. He closes on hydroelectric power, explaining how dams convert flowing water into electricity through turbines, and ends with a comparison of energy production across three states. The lecture runs through chapters on each resource in turn, giving a plain, data grounded survey of where modern electricity and fuel actually come from.