“This study is further validation of what we’ve been saying – that obtaining 20% or more of America’s electricity from wind turbines is an achievable and desirable goal for our economy, environment, and energy security.” said Bode. “Now the only question is whether Congress and the Administration will step up and enact the policies – particularly a strong Renewable Electricity Standard and robust transmission legislation – that will allow us to get there. The American people know that wind works for America and agree that Congress must act—according to a recent national poll conducted by a bipartisan team of pollsters, 77% of Americans believe Congress is focusing too little on increasing renewable energy resources."
The study, called the Western Wind and Solar Integration Study (WWSIS), examined several scenarios in which wind energy would provide up to 30% of the electricity for a large region of the Western U.S.
Among the key findings of the study:
* Obtaining 35% of the Western region’s electricity from renewable energy is technically achievable, with 30% provided by wind and 5% by solar energy;
* Achieving 30% wind could reduce emissions of carbon dioxide by up to 45%, nitrogen oxides by up to 50%, and sulfur dioxide by 30%;
* Adding 30% wind reduces overall power system operating costs by 40%, saving consumers money and protecting them from fuel price volatility;
* The scenario is feasible, cost effective, and reliable even without storage; and
* Transmission is critical for achieving higher wind penetrations, and the cost of this transmission is very small compared to the benefits of the wind energy that would be brought online.
The study also highlighted a number of grid operating reforms that will help facilitate the integration of wind energy. These cost-effective reforms will benefit consumers by making the power system more efficient and reliable, and these benefits are realized even on power systems without wind energy:
1. Substantially increase Balancing Area cooperation or consolidation, real or virtual (the West region can save $2 billion on spinning reserve costs alone by operating as 5 consolidated regions instead of many smaller regions);
2. Increase the use of sub-hourly scheduling for generation and interchanges (this one step alone cuts regulation reserve needs nearly in half);
3. Increase utilization of transmission;
4. Enable coordinated commitment and economic dispatch of generation over wider regions;
5. Use state of the art wind/solar forecasts in unit commitment/operations (in the 30% wind case, state-of-the-art forecasting saves $5 billion relative to not using a forecast);
6. Increase the flexibility of dispatchable generation where appropriate;
7. Commit additional operating reserves as appropriate;
8. Target new or existing demand response programs to accommodate increased variability and uncertainty;
9. Allow wind plants to provide down regulating reserves.
Western Wind and Solar Integration Study
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 turbines, 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.
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.
A copy of the study and its executive summary will be available at http://www.nrel.gov/wind/systemsintegration/wwsis.html