DOE reports show major potential for wave and tidal energy production near US coasts

21 January 2012

The US Department of Energy (DOE) released two nationwide resource assessments showing that waves and tidal currents off the nation’s coasts could contribute to the United States’ total annual electricity production. These new wave and tidal resource assessments, combined with ongoing analyses of the technologies and other resource assessments, show that water power, including conventional hydropower and wave, tidal, and other water power resources, can potentially provide 15% of our nation’s electricity by 2030.

The United States uses about 4,000 terawatt hours (TWh) of electricity per year. DOE estimates that the maximum theoretical electric generation that could be produced from waves and tidal currents is approximately 1,420 TWh per year, approximately one-third of the nation’s total annual electricity usage. Although not all of the resource potential identified in these assessments can realistically be developed, the results still represent major opportunities for new water power development in the United States, highlighting specific opportunities to expand on the 6% of the nation’s electricity already generated from renewable hydropower resources.

The two reports—“Mapping and Assessment of the United States Ocean Wave Energy Resource” and “Assessment of Energy Production Potential from Tidal Streams in the United States”—calculate the maximum kinetic energy available from waves and tides off US coasts that could be used for future energy production.

The total available wave energy resource along the US continental shelf edge, based on accumulating unit circle wave power densities, is estimated to be 2,640 TWh/yr, broken down as follows: 590 TWh/yr for the West Coast, 240 TWh/yr for the East Coast, 80 TWh/yr for the Gulf of Mexico, 1570 TWh/yr for Alaska, 130 TWh/yr for Hawaii, and 30 TWh/yr for Puerto Rico. Overall, as compared with the preliminary wave energy resource made by EPRI in 2004, this represents a 26% increase in the available resource estimate. Regionally, the increase is markedly greater for the East Coast than the West Coast and Alaska, because the 2004 EPRI estimates were rounded to the nearest 5 kW per m, and such rounding has a much greater effect for the lower wave power densities of the East Coast.

—Mapping and Assessment of the United States Ocean Wave Energy Resource

The West Coast, including Alaska and Hawaii, has especially high potential for wave energy development, while significant opportunities for wave energy also exist along the East Coast. Additionally, parts of both the West and East Coasts have strong tides that could be tapped to produce energy.

Earlier this year, DOE announced the availability of its national tidal resource database, which maps the maximum theoretically available energy in the nation’s tidal streams. This database contributed to the “Assessment of Energy Production Potential from Tidal Streams in the United States” report, prepared by Georgia Tech.

The wave energy assessment report, titled “Mapping and Assessment of the United States Ocean Wave Energy Resource,” was prepared by the Electric Power Research Institute (EPRI), with support and data validation from researchers at Virginia Tech and DOE’s National Renewable Energy Laboratory (NREL). The report describes the methods used to produce geospatial data and to map the average annual and monthly significant wave height, wave energy period, mean direction, and wave power density in the coastal United States. NREL incorporated the data into a new marine and hydrokinetic energy section in their US Renewable Resource atlas.

In addition to the wave and tidal resource assessments released today, DOE plans to release additional resource assessments for ocean current, ocean thermal gradients, and new hydropower resources in 2012. To support the development of technologies that can tap into these water power resources, DOE’s Water Power Program is undertaking a detailed technical and economic assessment of a wide range of water power technologies in order to more accurately predict the opportunities and costs of developing and deploying these innovative technologies. The Program is currently sponsoring more than 40 demonstration projects that will advance the commercial readiness of these systems, provide first-of-a-kind, in-water performance data that will validate cost-of-energy predictions, and identify pathways for large cost reductions.

Resources

• Assessment of Energy Production Potential from Tidal Streams in the United States

• Mapping and Assessment of the United States Ocean Wave Energy Resource