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Field guide

Ocean & marine energy

Oceans are enormous; marine electricity today is a postcard in a warehouse of potential.

Set the scene

Ocean energy includes tidal, wave, ocean thermal energy conversion (OTEC), and salinity-gradient technologies. IPCC AR6 WGIII notes marine energy remains a very small share of global electricity. Site-specific potential can be meaningful locally, but global deployment is limited today.

Signal, not noise

Three snaps from the evidence

3 beats
  1. 01

    IPCC AR6 WGIII states marine energy generation has remained at roughly about 1 TWh/yr since 2015—a very small global share.

  2. 02

    Tidal range or stream systems can be more predictable in specific regions; wave and OTEC technologies face engineering and cost hurdles.

  3. 03

    Impacts on marine ecosystems, fisheries, and coastal uses require careful, place-based assessment.

Chart break

Explore the data

Electricity production by source (terawatt-hours). Marine energy is typically a very small share globally—use this chart to compare the scale of sources; open the grapher page for definitions and datasets.

Chart: Our World in Data (CC BY). Each grapher page lists the underlying datasets, units, and processing notes—use it when citing numbers.

Open on Our World in Data

No fairy tales

Where it helps—and where it hurts

Strengths

  • Tidal regimes can be predictable in some locations, aiding planning compared with fully variable renewables.
  • Physical resource estimates for waves and thermal gradients are large in principle; niche opportunities exist.
  • Innovation can expand optionality for islands and coastal decarbonisation portfolios.

Limits & trade-offs

  • Global deployment is tiny today; costs and reliability remain uncertain at scale.
  • Harsh marine environments and corrosion raise maintenance and survivability challenges.
  • Conflicts can arise with shipping, defence, conservation, and coastal communities.

Read the receipts

Sources for this page

These entries are starting points for verification. Prefer the original report or dataset when checking numbers and figures.

  1. IPCC AR6 WGIII Ch. 6Clarke, L., Wei, Y.-M., De La Vega Navarro, A., Garg, A., Hahmann, A. N., Khennas, S., Azevedo, I. M. L., Loschel, A., Singh, A. K., Steg, L., Strbac, G., & Wada, K. (2022). Energy systems. In P. R. Shukla et al. (Eds.), Climate Change 2022: Mitigation of Climate Change (IPCC AR6 WGIII, Chapter 6). Cambridge University Press. https://doi.org/10.1017/9781009157926.008
  2. IEA RenewablesInternational Energy Agency. (2024). Renewables 2024: Analysis and forecast to 2030. IEA. https://www.iea.org/reports/renewables-2024
  3. Our World in DataRitchie, H., & Rosado, P. (2020). Electricity mix. Our World in Data. https://ourworldindata.org/electricity-mix (underlying grapher datasets include Ember and Energy Institute series, cited per chart metadata).