What is a renewable resource?

A renewable source is a substance of significant economic value that can be replenished or replaced in the same amount of time or less it takes to draw the supply down. Some renewable sources have a seemingly endless supply, like geothermal pressure, wind energy, and solar energy.

Other resources, such as biomass and wood are considered renewable, but a considerable amount of time and effort must be placed into their renewal. The energy that comes from renewable sources reduces the strain placed on the limited supply of fossil fuels. Since the supply will one day end, fossil fuels are considered to be nonrenewable resources. Relying on nonrenewable resources is unsustainable in the end.