According to a release, the report is valuable for decision-makers and utility executives because it compares estimates across six renewable energy technologies and unifies assumptions and methods. It shows the achievable energy generation of a particular technology given resource availability -- solar, wind, geothermal availability, etc. -- system performance, topographic limitations, and environmental and land-use constraints. The study includes state-level maps and tables containing available land area (square kilometers), installed capacity (gigawatts), and electric generation (gigawatt-hours) for each technology.
NREL's Anthony Lopez, a co-author of the study said, "Decision-makers using the study will get a sense of scale regarding the potential for renewables, and which technologies are worth examining. Energy modelers also will find the study valuable." NREL's Donna Heimiller, another co-author added, "This is intended to be a living document. We'll be frequently updating the information as we get more data."
According to the report, it is unique in unifying assumptions and application of methods employed to generate comparable estimates across technologies, where possible, to allow cross-technology comparison. Technical potential estimates for six different renewable energy technologies were calculated by NREL, and methods and results for several other renewable technologies from previously published reports are also presented.
The report presents the state-level results of a spatial analysis calculating renewable energy technical potential, reporting available land area (square kilometers), installed capacity (gigawatts), and electric generation (gigawatt-hours) for six different renewable electricity generation technologies: utility-scale photovoltaics (both urban and rural), concentrating solar power, onshore wind power, offshore wind power, biopower, and enhanced geothermal systems. Each technology's system-specific power density (or equivalent), capacity factor, and land-use constraints were identified using published research, subject matter experts, and analysis by the National Renewable Energy Laboratory (NREL). System performance estimates rely heavily on NREL's Systems Advisor Model (SAM) and Regional Energy Deployment System (ReEDS), a multiregional, multi-time period, geographic information system (GIS) and linear programming model. This report also presents technical potential findings for rooftop photovoltaic, hydrothermal, and hydropower in a similar format based solely on previous published reports.
The report notes, ". . .as a technical potential, rather than economic or market potential, these estimates do not consider availability of transmission infrastructure, costs, reliability or time-of-dispatch, current or future electricity loads, or relevant policies. Further, as this analysis does not allocate land for use by a particular technology, the same land area may be the basis for estimates of multiple technologies (i.e., non-excluded land is assumed to be available to support development of more than one technology)."