and ocean current energy in the Florida Straits. In addition, socioeconomic and environmental filters will ultimately limit the practical resource to only a fraction of the technical resource, so it is unlikely that the resource assessments, which at best provide only a partial assessment of the technical resource, could serve as a defensible estimate of the available practical resource. Although DOE may want overall numbers in order to compare individual MHK resources with one another or with other renewable resources, a single number is of limited value for understanding the potential contribution of MHK resources to U.S. utility-scale electricity generation. Instead, site-by-site analysis will be needed to estimate the resource that might ultimately be available for electricity generation. This number is likely to be much smaller than the numbers generated by national resource assessments.
Another issue that applies broadly to the entire DOE-funded assessment efforts was the coordination among and consistency between individual resource assessments. These efforts suffered from a lack of coordination and consistency in terms of methodology, validation, and deliverable products. Each of the assessment groups chose its own methodologies, and while the committee understands that there was likely to be variation simply because the resource types differ, greater coordination at the outset could have discerned some commonalities that would have allowed easier comparison of the assessments. In addition, each validation group chose its own method, which also led to inconsistent results. In some cases, the method appeared to be less of a validation than a spot-checking of results with varying degrees of thoroughness. The committee is also concerned about the scientific validity of some assessment conclusions; these concerns are addressed in later chapters. The lack of coordination and consistency also affected the GIS database products. While some are already integrated into GIS Web applications hosted by DOE’s National Renewable Energy Laboratory (MHK Atlas and River Atlas5), others are currently hosted on platforms operated by individual assessment groups. Given that one of DOE’s objectives is to compare the various MHK resources with one another and with other renewable energy resources, the lack of coordination and consistency between the assessment groups was counterproductive.