Ocean Wave Resource Potential
Energy from the ocean can be harnessed in many ways and forms. Wind energy, tidal energy, and wave energy are all worthwhile possibilities. MarineCadastre.gov’s Ocean Wave Resource Potential data set shows users the predicted mean wave energy density within U.S. waters. The National Renewable Energy Laboratory (NREL), in partnership with NOAA’s National Centers for Environmental Prediction (NCEP) , the Electric Power Research Institute (EPRI), and Virginia Tech, compiled more than four years’ worth of modeled data to create this data set, which will assist the ocean planning community and in particular those who are developing devices to harvest wave energy and need to find the best places to put them. So what is important for ocean planners to know about the Ocean Wave Resource Potential data set?
- Wave energy is a viable option. Waves are ever-present to varying degrees, and developers are working on new technologies that allow energy harnessing devices to withstand and even continue collecting energy during large storm events. Developers continue to explore new ways to make the current wave energy harnessing technologies more efficient and resilient. Several countries have already begun testing these products, and some countries, such as Portugal and Scotland, have already started utilizing wave energy.
- The data vary in time and space. In the same way an electric bill is measured each month, NREL measured average monthly wave energy potential. The electric company does not care if a household or business used a great deal of electricity in the first two weeks of the month and then no electricity in the second two weeks. The company only cares how much was used for the whole month. Wave energy data and the models used to generalize these data do not represent the exact wave energy fluctuation at any given moment; they simply represent how much energy crossed the energy harnessing device over a set time period (month or year). In this case, NREL used data gathered over more than four years (51 months) to create this data set. By digging into the data set, users can find the monthly variability.
- The wave crest is the length of the wave. The crest is perpendicular to the direction the wave is traveling and is not the distance the wave crest travels. This distinction is important when considering the units, kilowatts per meter. In this case, the units represent the average energy crossing a meter of wave crest. This is a theoretical maximum, representing all energy present in the motion of the water. The actual efficiency of wave conversion devices is relatively small, so the actual amount of electricity generated per meter of wave crest will only be a small fraction of the theoretical numbers presented here. This study does not address the efficiency of wave devices.
Quick Caveats. The data are average values and thus do not represent peak power values. The data do not provide high enough resolution information for device developers to make development decisions. Planners should conduct further research after using this data set as a starting point. There are known large effects on wave characteristics at depths shallower than approximately 20 meters (65 feet) on the East Coast and 50 meters (160 feet) on the West Coast. Therefore, reliable site-specific information in shallow waters can only be produced using results from models with higher spatial resolution that include shallow-water physics. Planners interested in these areas should consult an expert on shallow-water wave dynamics and modeling. MarineCadastre.gov makes the annual data available in an ArcGIS-ready format. Files of gridded monthly and annual wave energy estimates are available through the Source Data link within the Properties page. Go to the full report to learn more about the process behind gathering the raw data. Note: the report is comprehensive and very detailed.
George Scott, Scientist, National Wind Technology Center, National Renewable Energy Laboratory
Nick Langle, Data Analysis and Visualization Team, National Renewable Energy Laboratory
Brooke White, Knauss Marine Policy Fellow at U.S. Department of Energy
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