Energy systems

Fossil Fuels

Meaning statusEstablishedSource recordDirect document linkedWhy these are different

Definition

Fossil fuels are hydrocarbon-containing materials of biological origin, formed from the buried remains of plants and animals over geological time, that are burned to release energy. The category includes coal, petroleum and its refined products, and natural gas, along with derivatives such as oil shales, bitumens, tar sands, and heavy oils. They are non-renewable resources.

References

Encyclopaedia BritannicaFossil fuel (hydrocarbon materials of biological origin; coal, petroleum, natural gas, oil shales, bitumens, tar sands, heavy oils; nonrenewable; >80% of industrialized-country energy)

definition and energy share

Overview

What it means

Fossil fuels powered industrialisation and still supply more than 80% of energy in industrialised countries, but their combustion is the dominant source of anthropogenic carbon dioxide and a major source of air pollution. Their geological origin means reserves are finite and unevenly distributed, shaping global trade and geopolitics.

How it is used

The term frames the central divide in energy policy between conventional and renewable sources; it appears throughout climate negotiations, national energy statistics, and decarbonisation planning.

Why it matters

Understanding what counts as a fossil fuel — and what "unabated" use means — is a prerequisite for reading phase-out commitments, carbon budgets, and energy-transition scenarios.