Tidal energy is powered by the natural rise and fall, or surge, of ocean tides and currents. While hydroelectricity refers to the use of dams to produce energy from water, tidal energy uses the ocean/sea's tides. 

Geothermal energy uses drills to harness the Earth's essentially limitless supply of central heat. There are two main uses for geothermal energy: to convert to usable electricity and to heat homes.

Concentrated solar power (CSP), unlike solar PV, concentrates the sun's heat energy. The intense heat is used to generate electricity. While CSP is not widespread, it is gaining momentum as a result of Bill Gate's secret solar company. 

Hydroelectricity uses the force of moving water to generate electricity. Hydroelectricity typically employs river dams to generate faster waters. Hydroelectricity is one of the most prevalent types of renewable energy but also has some other environmental drawbacks.

Wind energy uses the wind to turn turbines that produce electricity through motion. It relies on consistent wind at higher altitudes and is typically employed through commercial wind farms, although there are some residential applications.

Solar energy harnesses the sun's light energy — photons — to generate electricity through solar panels. Solar panels can be employed by an individual (on a house), or commercially via large-scale solar farms.