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Ocean Energy Results – Life Cycle Assessment Review

Chart that shows life cycle greenhouse gas emissions for ocean power technologies.  For help reading this chart, please contact the webmaster.

Estimates of life cycle greenhouse gas emissions of wave and tidal range technologies.
Credit: Lewis, A., S. Estefen, J. Huckerby, W. Musial, T. Pontes, J. Torres-Martinez, 2011: Ocean Energy. In IPCC Special Report on Renewable Energy Sources and Climate Change Mitigation [O. Edenhofer, R. Pichs-Madruga, Y. Sokona, K. Seyboth, P. Matschoss, S. Kadner, T. Zwickel, P. Eickemeier, G. Hansen, S. Schlömer, C. von Stechow (eds)], Cambridge University Press. Figure 6.11

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Few life cycle assessments have been conducted on emerging technologies like ocean energy systems, which include tidal and ocean current, ocean thermal energy conversion, and salinity gradient devices.

To better understand ocean energy systems, NREL completed a comprehensive review and analysis of life cycle assessments on wave and tidal power systems published between 1980 and 2010.

The figure below summarizes the results of NREL's systematic review. Life cycle assessments estimate that full life cycle CO2-equivalent emissions for geothermal energy technologies are less than 23 g CO2eq/kWhe for wave and tidal technologies, with a median estimate of 8 g CO2eq/kWhe for wave energy.

In comparison to fossil energy generation technologies, the life cycle greenhouse gas (GHG) emissions from ocean energy devices appear low. Insufficient studies have been conducted on wave and tidal range devices to determine whether there are any significant differences between them regarding GHG emissions. Additional life cycle assessments for all ocean energy technologies are needed to corroborate the results published to date and to better understand sources of variability.