Power in ocean waves originate as wind energy that is transferred to the sea surface when wind blows over large areas of the ocean. The resulting wave field consists of a collection of waves at different frequencies traveling in various directions delivering their power to near shore areas, whereas ocean tides are a response to gravitational forces exerted by the Moon and the Sun. The limitless potential of tidal power for human use has traditionally led to proposals that employ various schemes to harness this generated power. Now, as marine and hydrokinetic resources increasingly become a part of energy regulatory, planning, and marketing activities in the United States, assessments are being conducted for future development. In particular, state-based renewable portfolio standards and federal production and investment tax credits, have led to an increased interest in the possible deployment of marine and hydrokinetic (MHK) technologies.

Assessment of Marine and Hydrokinetic Energy Technology: Interim Letter Report provides an evaluation of detailed appraisals for the Department of Energy estimating the amount of extractable energy from U.S. marine and hydrokinetic resources. In order to assess the overall potential for U.S. MHK resources and technologies, this report evaluates the methodologies, technologies, and assumptions associated with the wave and tidal energy resource assessments.