# Ocean thermal gradient: Overview

Power from the warm top and cold bottom of the sea

Source page: https://www.materialinsights.org/energy/e_ocean_thermal/overview/

What this tile covers The temperature gap between warm surface water and cold deep water. Share of use 0% share of world energy supply (2024)

Share of world total energy supply, 2024 (latest year where noted). Denominator is the Energy Institute Statistical Review 2025 total of 592.2 EJ (physical energy content method). Flows EI omits (traditional biomass via WBA, solar and geothermal heat, food energy) are set against the same 592.2 EJ, so shares sum to slightly more than 100%. The largest operating OTEC plants are about 0.1 MW, so the share rounds to zero. Source: [Makai Ocean Engineering connects world's largest OTEC plant to U.S. grid](https://www.power-eng.com/2015/08/31/makai-ocean-engineering-connects-world-s-largest-otec-plant-to-u-s-grid/), Power Engineering.

#### Key facts

| **Origin** | Indirect solar |
|---|---|
| **Renewable** | Yes |

#### Included from the reference tables

- Ocean thermal energy conversion (OTEC)

#### Also in Solar-derived flows
[Sun Sunlight](https://www.materialinsights.org/energy/e_sunlight/)[Wd Wind](https://www.materialinsights.org/energy/e_wind/)[H2O Water cycle](https://www.materialinsights.org/energy/e_hydro/)[Wv Ocean waves](https://www.materialinsights.org/energy/e_waves/)[Oc Ocean currents](https://www.materialinsights.org/energy/e_currents/)[Sal Salinity gradient](https://www.materialinsights.org/energy/e_salinity/)[Bm Biomass](https://www.materialinsights.org/energy/e_biomass/)[Amb Ambient heat](https://www.materialinsights.org/energy/e_ambient/)[Mu Muscle power](https://www.materialinsights.org/energy/e_muscle/)

Explore paths from here
 More on this tile in the tabs above: how energy resides, abundance, fluctuation in time, across the earth, impact on nature.

## Other sections

- [Summary](https://www.materialinsights.org/energy/e_ocean_thermal/index.md)
- [Correlation](https://www.materialinsights.org/energy/e_ocean_thermal/correlation/index.md)
- [How energy resides](https://www.materialinsights.org/energy/e_ocean_thermal/resides/index.md)
- [Abundance](https://www.materialinsights.org/energy/e_ocean_thermal/abundance/index.md)
- [Fluctuation in time](https://www.materialinsights.org/energy/e_ocean_thermal/time/index.md)
- [Across the Earth](https://www.materialinsights.org/energy/e_ocean_thermal/geography/index.md)
- [Impact on nature](https://www.materialinsights.org/energy/e_ocean_thermal/nature/index.md)
- [Relationships](https://www.materialinsights.org/energy/e_ocean_thermal/links/index.md)