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Western Wind and Solar Integration Study

This partial map of the western United States shows the WestConnect group of utilities.

The Western Wind and Solar Integration Study (WWSIS) is one of the largest regional wind and solar integration studies to date. It was initiated in 2007 to examine the operational impact of up to 35% energy penetration of wind, photovoltaics (PV), and concentrating solar power (CSP) on the power system operated by the WestConnect group of utilities in Arizona, Colorado, Nevada, New Mexico, and Wyoming (see study area map). WestConnect also includes utilities in California, but these were not included because California had already completed a renewable energy integration study for the state. This study was set up to answer questions that utilities, public utilities commissions, developers, and regional planning organizations had about renewable energy use in the west:

  • Does geographic diversity of renewable energy resource help mitigate variability?
  • How do local resources compare to out-of-state resources?
  • Can balancing area cooperation help mitigate variability?
  • What is the role and value of energy storage?
  • Should reserve requirements be modified?
  • What is the benefit of forecasting?
  • How can hydropower help with integration of renewables?

The Western Wind and Solar Integration Study is sponsored by the U.S. Department of Energy (DOE) and run by NREL with WestConnect as a partner organization. The study follows DOE's 20% Wind Energy by 2030 report, which did not find any technical barriers to reaching 20% wind energy in the continental United States by 2030. This study and its partner study, the Eastern Wind Integration and Transmission Study, performed a more in-depth operating impact analysis to see if 20% wind energy was feasible from an operational level. In DOE/NREL's analysis, the 20% wind energy target required 25% wind energy in the western interconnection; therefore, this study considered 20% and 30% wind energy to bracket the DOE analysis. Additionally, since solar is rapidly growing in the west, 5% solar was also considered in this study.

Western Wind Dataset

A primary task of the Western Wind and Solar Integration Study is to produce a comprehensive dataset that could be used to model the build-out of potential wind plants in the western United States. The Western Wind Dataset will be the basis for assessing the operating impacts and mitigation options due to the variability and uncertainty of wind power on the utility grids.

The goal of the Western Wind and Solar Integration Study is to understand the costs and operating impacts due to the variability and uncertainty of wind, PV, and CSP on the grid. This is mainly an operations study, (rather than a transmission study), although different scenarios model different transmission build-outs to deliver power. Using a detailed power system production simulation model, the study identifies operational impacts and challenges of wind energy penetration up to 30% of annual electricity consumption.

More Information

The following documents are available as Adobe Acrobat PDFs. Download Adobe Reader.

Publication cover.

How do Wind and Solar Power Affect Grid Operations: The Western Wind and Solar Integration Study (PDF 1.5 MB). (September 2009). Lew, D.; Milligan, M.; Jordan, G.; Freeman, L.; Miller, N.; Clark, K.; Piwko, R. To be presented at the 8th International Workshop on Large Scale Integration of Wind Power and on Transmission Networks for Offshore Wind Farms, 14-15 October 2009, Bremen, Germany.

Publication cover.

Large-Scale Wind Integration Studies in the United States: Preliminary Results (PDF 853 KB). (September 2009). Milligan, M.; Lew, D.; Corbus, D.; Piwko, R.; Miller, N.; Clark, K.; Jordan, G.; Freeman, L.; Zavadil, B.; Schuerger, M. To be presented at the 8th International Workshop on Large Scale Integration of Wind Power and on Transmission Networks for Offshore Wind Farms, 14-15 October 2009, Bremen, Germany.

Publication cover.

Development of Regional Wind Resource and Wind Plant Output Datasets (PDF 5.9 MB). (2008). 3TIER created the Western Dataset with oversight and assistance from NREL. 3TIER has completed this final report describing the overall project detailing the modeling and inputs. Read more about the Western Wind Dataset.