The following is a brief explanation of the major sources of renewable energy. 

Biomass:  Energy is created by burning organic material that would otherwise naturally decompose.  The input materials for a biomass system are renewable as they can be replaced in a few years time, whereas fossil fuels take centuries to replenish. 

Wind:    Wind energy comes from the constant changes in air currents around the Earth, making it a continuously renewing energy source.   Wind power is collected on wind farms through the use of turbines.

Solar:  Solar power captures the energy from the sun, mainly using photovoltaic cell technology, and converts it into electricity.  This source can also be used for heating, hot water, and lighting.

Geothermal:  Energy is produced by accessing natural heat sources located underground in a geothermal deposit. 

Landfill Gasses:  Energy from this source is produced by capturing the gasses released by the decomposition of waste products.  About half of this gas is methane, which can be separated and burned in a power plant to produce electricity or heat.

Municipal Solid Waste:  This consists of solid, liquid, gaseous, or semi-solid waste material that is burned as a fuel source.  These can be from industrial, commercial, mining, agricultural, or residential sources.  Specific items, such as domestic sewage and radioactive material, are excluded from use as a fuel source.

Hydroelectric:   Hydroelectric uses water as the source of energy.  This type of renewable energy is produced by using a dam to control the flow of water as it passes through the facility.     

Hydrokinetic:  Also referred to as Marine Energy, is similar to Hydroelectric in that water is used to produce electricity; however, hydrokinetic does not use a dam.  Instead, hydrokinetic uses free flowing water, ocean tides, waves, and currents to power the turbines.