The Sun. Most of the energy we capture for use on Earth originates in the nuclear reactions powering our Sun. Coal, oil, natural gas, biomass, and even the wind and hydropower we harness to generate electricity, originally derive their energy content from the Sun. Learn how our local star is the ultimate energy source.% of our total energy use comes from renewable energy sources, such as wind, solar, and hydropower. Renewable energy sources lessen our dependence on foreign energy and do not emit greenhouse gases. Experts predict that over the next two decades, renewable energy will provide a growing portion of U.S. overall energy.