Screenshot from NREL interactive atlas for renewable energy showing energy intensities for solar photovoltaic energy (yellow) and biomass residue (green). Credit: NREL.
People in the renewable and alternative energy business talk about an “energy portfolio,” where the electricity deposited on the local grid will be generated from a mix of what the local natural resources offer (solar, wind, wave power, geothermal) and power plants that can be built anywhere (nuclear, coal).
Like all natural resources, the distribution of energy resources varies. The National Renewable Energy Laboratory in Golden, Colo., recently released an interactive tool, the RE Atlas, that maps the locations of potential renewable energy resources in the US.
In the press release, Dan Getman, whose NREL team developed the tool says, “Ease of use and breadth of data make RE Atlas an excellent tool for policymakers, planners, energy developers, and others who need to better understand the renewable resources available in the United States. RE Atlas is an important addition to NREL’s suite of geospatial tools, because it brings together so many renewable energy datasets in one easy-to-use tool.”
Those datasets include a rich collection NREL maps of energy resources, geographic data and maps, EPA site information, links to research and much more. The energy resources that the atlas maps are
• Hydro (existing small projects)
• Geothermal (potential hydrothermal sites)
• Biomass residue
• Geothermal (enhanced geothermal system)
• Concentrated solar power
• Solar photovoltaic
• Wind speed – offshore
• Wind power class – onshore
• Wave power density.
Renewable energy resources are distributed as one would expect across the country, and it is interesting to see how broad the swaths of intensity are. For example, solar photovoltaic is most intense in the most southern regions of the Southwest, but it is decently intense in the entire southwestern quadrant of the US. Biomass, too, which would seem to be region-independent, is most intense across the Midwest from the Dakotas down through Missouri.
The intensities of each energy resource are not given in a common energy unit like joules or BTU, but according to the units used to quantify that energy type, which makes it difficult to compare magnitudes of energy available unless you are familiar with the unit conversions. For example, the units for solar photovoltaic energy are kWh/m2/day, biomass is expressed in thousand tons/year, geothermal is categorized into ranges (class 1-5), etc.