Any form of organic material that can be used as an energy source: Forest, mill, and agricultural residues, urban wood wastes, and dedicated energy crops are all types of biomass resources .

An estimate of the quantities of such resources that are available by location and price levels: Biomass resource assessments must consider different factors, like practical obtainability and technical practicability, among others, to determine the usefulness of using biomass as an energy.

The source of hot water and steam below the surface of the Earth: The geothermal resources range from shallow ground to hot water and rock several miles below the Earth's surface, and even farther down to the extremely hot molten rock called magma.

Mile-or-more-deep wells can be drilled into underground reservoirs to tap steam and very hot water that can be brought to the surface for use in a variety of applications. In the United States, most geothermal reservoirs are located in the western states, Alaska, and Hawaii.

Lithium and its future.

A limited natural resource known as Lithium which may be in greater global demand.