Exajoule (EJ)
An SI unit of energy equal to 10¹⁸ joules (277.8 TWh), used to express national and global primary energy supply.
The exajoule is one quintillion joules. It is the standard unit of the Energy Institute Statistical Review of World Energy and is widely used by the IEA and IPCC for global primary energy balances.
1 EJ = 277.78 TWh = 23.88 Mtoe = 0.9478 quad (10¹⁵ BTU)
1 quad = 1.055 EJ
1 EJ ≈ 163 million barrels of oil equivalent (at 6.12 GJ/boe)
1 EJ ≈ 26–28 billion m³ of natural gas
Scale references: global primary energy consumption reached about 620 EJ in 2023 (Energy Institute 2024), of which oil about 196 EJ, coal about 164 EJ and natural gas about 144 EJ. World electricity generation of 31,772 TWh in 2025 corresponds to about 114 EJ of electrical output. United States primary energy is about 94 quads (roughly 99 EJ, EIA), China about 170 EJ, Germany about 11 EJ.
When renewable electricity is converted to EJ, the accounting convention matters. The Energy Institute uses the substitution method (equivalent fossil input at about 40% efficiency), so 1 TWh of wind counts as about 9 PJ; the IEA and Eurostat use the physical energy content method, counting it as 3.6 PJ. This can change the reported renewable share of primary energy by a factor of more than two.
Related terms
All terms →- Joule (J)
The SI unit of energy, work and heat: the work done by a force of one newton over one metre, or one watt sustained for one second.
- Terawatt-hour (TWh)
A unit of energy equal to one billion kWh (10⁹ kWh) or 3.6 PJ; used for national and global electricity generation and consumption.
- Primary energy
Energy in its raw natural form before conversion, such as crude oil, coal, natural gas, uranium, biomass, and the electricity or heat from renewables.
- Tonne of oil equivalent (toe)
A conventional energy unit equal to 41.868 GJ (10 Gcal, 11.63 MWh), the nominal heat content of one tonne of crude oil, used in energy balances.
- MMBtu
One million British thermal units (1.05506 GJ, 293.07 kWh); the standard pricing unit for natural gas and LNG in the United States and Asia.