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Sources of energy
Beginner
Fossil, nuclear, solar, wind, hydro and geothermal sources.
Primary sources: fossil fuels, nuclear, solar, wind, hydro, geothermal and biomass. Sources differ in energy density, cost, emissions and availability.
Gasoline holds about 46 MJ/kg, a battery about 0.7 MJ/kg.
Electricity is a carrier, not a source.
In more detail
Energy sources include fossil fuels, nuclear fuel, solar, wind, hydroelectric, geothermal and biomass. Each converts a store of energy into a usable form, such as electricity.
Real-world uses
- Countries plan energy mixes using data on fuel supply and cost.
- Homeowners choose solar panels or heat pumps based on energy sources.
- A national grid draws electricity from coal, gas, nuclear, wind, solar and hydro sources, each with different energy input.
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Frequently asked questions
Is energy ever created at a power plant?
No. It converts energy from the source, such as chemical energy in coal or kinetic energy in wind.
Which energy source is best?
There is no single answer. Each has trade-offs in cost, reliability, emissions and land use.
Which energy source is best?
There is no single best source. Each has trade-offs in cost, reliability, emissions and land use that depend on local conditions.
Related topics in Work, Energy & Power
Heat as energy transfer · Mechanical equivalent of heat · Mass–energy equivalence · Renewable energy · Conservation of energy in collisions · Virial theorem