Abstract
This report provides a concise and consolidated overview of the Unites States’ marine energy resources. The results reported herein are primarily based on U.S. Department of Energy (DOE)-funded marine energy resource assessments in the following technology areas: wave, tidal currents, ocean currents, ocean thermal gradients, and river currents (Jacobson, Hagerman, and Scott 2011; Haas et al. 2011; Haas 2013; Ascari et al. 2012). This report also incorporates recent updates and refinements to the U.S. wave and tidal resource assessments performed by several national laboratories (Kilcher, Garcia-Medina, and Yang 2021; Kilcher, Haas, and Muscalus 2021). Many of these refinements were undertaken to address feedback from the National Research Council’s evaluation of the original resource assessments (National Research Council 2013). Further, this report refines the analysis published to date by identifying the marine energy resources available in each state or region to the extent practical. In short, this report summarizes the best available data on U.S. marine energy resources at the state, regional, and national scales.
While marine energy technologies are still at the relatively early stages of development, the resource potential is immense and distributed widely across the nation’s coastlines and rivers. We use the following definitions to frame the conversation about marine energy resource potentials (International Electrotechnical Commission 2020):
- Theoretical resource—the energy available in the resource
- Technical resource—the proportion of the theoretical resource that can be captured using existing technology options
- Practical resource—the proportion of the technical resource that is available after consideration of external constraints. Where ‘external constraints’ are the socioeconomic, environmental, regulatory, and other competing-use constraints that determine whether a project is viable at a specific site.
In this work, we focus on the technical resource within the nation’s exclusive economic zone (EEZ) that can be harnessed for large-scale (megawatt- to gigawatt-scale) energy generation. It does not include marine energy resources that may be valuable to many blue economy applications, which often have lower power requirements and can use low-energy marine energy resources that are not sufficiently energetic for large-scale energy generation. Accordingly, some locations where this report indicates there is little or no technical resource may still have marine energy resources that are sufficient to provide power for blue economy applications.
The total marine energy technical resource in the 50 states is 2,300 TWh/yr, equivalent to 57% of the electricity generated by those states in 2019. The nation’s Pacific and Caribbean territories and freely associated states add an additional 4,100 TWh/yr of ocean thermal energy resource. While we do not attempt to forecast the future deployment of marine energy technologies, it is important to note that even if only a small portion of the technical resource potential is captured, marine energy technologies would make significant contributions to our nation’s energy needs. For example, utilizing just one-tenth of the technically available marine energy resources in the 50 states would equate to 5.7% of our nation’s current electricity generation—enough energy to power 22-million homes (U.S. Energy Information Administration 2020) (Figure ES-1). Assuming this energy could be generated at capacity factors between 30% and 70%, this would translate to between 40 GW and 90 GW of marine energy projects.
Marine energy resources are distributed throughout the United States and provide unique opportunities to different states and regions. Massive quantities of wave energy arrive at our coastlines every year, and this resource is particularly energetic along the nation’s Pacific shorelines (California, Oregon, Washington, Alaska, and Hawaii). Tidal energy, perhaps the most predictable renewable energy resource, could play a major role in Alaska’s electricity generation and could realistically contribute sizable quantities of power in Washington state and several Atlantic states. Ocean current energy, which is primarily contained in the Gulf Stream, has the potential to provide steady, reliable power to homes in North Carolina, South Carolina, Georgia, and Florida. Ocean thermal energy is another significant opportunity for parts of the Atlantic coast as well as the Gulf Coast states, Hawaii, and U.S. Pacific territories and freely associated states. Finally, the nation’s riverine resource can be harnessed without the need for dams or river diversion to provide reliable power throughout the country.