Marine Energy Resource Assessment and Characterization

To understand the full potential of our nation's water resources, the Water Power Technologies Office (WPTO) conducted the following resource assessments:

• Waves—energy contained in ocean surface waves;
• Tidal streams—energy contained in the flow of water from tides;
• Ocean currents—energy contained in the flow of water resulting from large-scale ocean circulation patterns;
• River currents—energy contained in rivers that can be harnessed without flow diversion structures; and
• Ocean thermal gradients—energy contained in the temperature difference between ocean surface and deeper waters.

There are three types of resource assessments:

• Theoretical resource potential—annual average amount of physical energy that is theoretically available;
• Technical resource potential—portion of a theoretical resource that can be captured using a specific technology; and
• Practical resource potential—portion of a technical resource that is available after other economic, environmental, and regulatory considerations are factored in.

WPTO published a summary of these energy assessments titled “Marine Energy in the United States: An Overview of Opportunities” in early 2021. The charts and tables below provide high-level overviews of the results presented in the summary.

The following table is a reference for the theoretical and technical levels of U.S. marine energy resource potential.