Primary & Secondary Energy Sources: What They Are, & Examples

There’s different forms of primary energy sources, and also secondary energy sources.

In this guide, we explain what each one is, and give examples of each.


Summary – Primary and Secondary Energy Sources

Primary energy sources are sources of energy found in a raw form in nature

Primary energy often has to be converted or transformed into more usable secondary sources of energy

There’s several examples of both primary energy sources and secondary energy sources, and we list them in the guide below

We also give examples of which primary energy sources are converted into which secondary energy sources in the guide below


What Are Primary Energy Sources?

Primary energy sources are usually natural resources or raw materials found in nature

They may also sometimes be refined resources

They usually undergo some type of energy conversion process or energy transformation process before they become usable energy

Conversion of energy happen via extracting, processing, refining, and combusting, amongst other stages of an energy conversion process


What Are Secondary Energy Sources?

Secondary energy sources usually come from primary energy sources 

This happens via energy conversion or energy transformation, or via the energy being stored

Secondary energy is essentially a good that has been changed from it’s original state to another state for ease of consumption, convenience, or to be a more usable form of energy than a primary energy source

Some reports refer to secondary energy sources as ‘energy carriers’, as they help move useable energy from one place to another

Coal undergoes an energy conversion process (at coal power plants) into a secondary energy source in the form of electricity


The two most well-known [secondary energy sources and] energy carriers are electricity and hydrogen (


Examples Of Primary Energy Sources

Examples of primary energy sources might include:

– Coal

– Raw oil

– Natural gas

– Wind

– Sun (which can be used in solar PV)

– Streaming (or moving) water (which can be used in hydropower in the case of rivers, or ocean based energy in the case of waves or tides)

– Uranium (used in nuclear fuel)

– The Earth’s heat (which can be used in geothermal energy)

– Wood


Examples Of Secondary Energy Sources

– Gasoline (also called petrol)

Comes from the primary product of crude oil

Is used in motor transport


– Electricity

Primary energy sources are converted into electricity

There’s a whole range of primary energy sources that can be used to make electricity

Electricity is carried through power lines and other transmission infrastructure, and is used in homes, at businesses, and so on 


– Hydrogen

Comes mainly from fossil fuels

But can also be made from renewable energy sources


Examples Of Converting Primary Energy Sources Into Secondary Energy Sources


Crude oil must be put through an oil refinery before it turns into secondary fuel (useable fuel) like gasoline, diesel or kerosene.

Coal is usually put into a coal-fired power plant to generate electricity

Wind must be harnessed by a wind turbine before it can generate electricity mentions that petrol, and also electric energy are examples of secondary energy sources:

[An example of a secondary energy source is] petrol, that derives from the treatment of crude oil and electric energy, obtained from the conversion of mechanical energy (hydroelectric plants, Aeolian plants), chemical plants (thermoelectric), or nuclear (nuclear plants).

Electric energy [is a secondary energy source that] is produced by electric plants, i.e. suitable installations that can transform primary energy (non-transformed) into electric energy.


In the case of geothermal and solar thermal, heat is the primary energy which is converted into geothermal or solar electricity 


What About Bioenergy?

Bioenergy comes from biomass

Biomass might be the primary energy, which is converted into bioenergy or biofuel goes into more detail about bioenergy


More Information On Primary & Secondary Energy Sources provides some good examples of primary energy sources, energy breakdown processes, and secondary energy sources.














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