Tides: Abundance
A fifth of world energy dissipated, a sliver captured
What this tab covers How much of this energy there is: the natural flow or stock, the share that could be harnessed, and how much is used today, compared with world primary energy use (592 EJ in 2024).The tides dissipate about 3.3-4 TW worldwide, roughly a fifth of world primary energy, of which perhaps 1 TW is near coasts. Actual output is about 1 TWh a year, a few millionths of world energy use.
A flow: renewed continuouslyHow much there is
| Measure | Value | Compared with world energy use | Note |
|---|---|---|---|
| Total tidal dissipation | about 3.3-4 TW5 | about 0.18-0.21 times world primary energy (104-126 EJ/yr vs 592 EJ) | Derived from Egbert and Ray, who found that the 1 TW dissipated in the deep ocean is 25-30% of the total |
| Deep-ocean dissipation | about 1 TW5 | about 0.05 times world primary energy | Spent mixing the deep ocean, far from any coast; the rest is lost in shallow seas |
| Technically harvestable resource near coasts | about 1 TW2 | about 0.05 times world primary energy (about 31.5 EJ/yr) | Estimate by several sources quoted by IRENA |
| Global ocean power capacity, end 2024 | about 513 MW6 | negligible | Almost all in two tidal range plants: Sihwa (254 MW) and La Rance (240 MW); 1.6 MW was added in 2024 |
| Annual output of the two big barrages | about 1.1 TWh/yr2 | about 0.0007% of world primary energy | La Rance about 540 GWh and Sihwa about 552 GWh per year |
| World primary energy consumption, 2024 | 592 EJ1 | baseline | Energy Institute Statistical Review of World Energy 2025 (total energy supply) |
The tidal flow is large in absolute terms but small against human demand: even capturing the whole of it would cover only about a fifth of today's primary energy, and most of it is spent in the deep ocean or across wide shelves where it cannot be tapped. The coastal, technically reachable share is roughly 1 TW.
Use remains tiny. Two barrages, La Rance in France (1966) and Sihwa in Korea, provide most of the world's tidal electricity. Tidal stream turbines in Europe produced 13.4 GWh in 2024, 10 GWh of it at MeyGen in Scotland, which has delivered over 70 GWh since 2018.
Sources
- Statistical Review of World Energy 2025 (74th edition): world total energy supply 592 EJ in 2024 (physical energy content method), the baseline for all vs_world comparisons Energy Institute, 2025
- Tidal Energy: Technology Brief IRENA, 2014
- Significant dissipation of tidal energy in the deep ocean inferred from satellite altimeter data (Egbert and Ray, Nature 405) Nature (abstract via RePEc), 2000
- Renewables 2025 Global Status Report: Ocean power REN21, 2025