This document summarizes key points about various renewable energy sources including wind, solar, geothermal, and hydroelectric power. It discusses what each energy source is, provides some history and examples of implementations. Wind energy is captured from turbines converting wind's kinetic energy. Solar energy uses photovoltaic cells to convert sunlight into electricity. Geothermal energy harnesses heat from within the earth. Hydroelectric power uses the force of moving water to turn turbines and generate electricity. The document highlights examples of each type of renewable energy being utilized both globally and within states like Idaho.