As elaborated on in the sections that follow, the committee concludes that the overall approach taken by the wave resource and tidal resource assessment groups is a useful contribution to understanding the distribution and possible magnitude of energy sources from waves and tides in U.S. waters. However, the committee has concerns regarding the usefulness of aggregating the analysis to produce a “single number” estimate of the total national or regional theoretical and technical resource base (defined in the section below entitled “Conceptual Framework") for any one of these sources. The committee also has some concerns about the methodologies and assumptions, as detailed in the sections below. For the wave resource assessment, the committee is particularly concerned with the extension of the analysis into shallow depths, where the modeling is most inaccurate. One important issue for the tidal resource assessment is the lack of clarity on how the assessment group will incorporate any sort of technological considerations into its resource assessment. The committee is also concerned about the limited scope of the assessments’ validation exercises. These issues are discussed further below.
MOTIVATION FOR AND PURPOSE OF THE INTERIM REPORT
Marine and hydrokinetic resources are increasingly becoming part of energy regulatory, planning, and marketing activities in the United States and elsewhere. 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 MHK technologies. This interest is reflected in the number of requests for permits for wave, current, tidal, and river-flow generators that have been filed recently with the Federal Energy Regulatory Commission (FERC); at the end of 2010 FERC had issued preliminary permits for 110 projects and had another 12 preliminary permits pending. It should be noted that although permit activity is a measure of the potential interest in MHK resource development, it is not a reliable predictor of the future development of Hydrokinetic resources because developers apply for permits before planning the facility or obtaining financing.
In order to assess the overall potential for U.S. MHK resources and technologies, the DOE is funding the following: (1) detailed resource assessments for estimating what the DOE terms the “potential extractable energy” for each resource and (2) projects for generating the technology-related data necessary for estimating the expected performance of the wide variety of technology designs currently under consideration (DOE, 2010; Battey, 2010, 2011). The objective of the DOE’s work in the area of MHK resource assessments is to help the DOE prioritize its overall portfolio of future research, increase the understanding of the potential for MHK