This is an excerpt from EERE Network News, a weekly electronic newsletter.

May 26, 2010

NREL Study: Western Grid Can Handle Increased Wind and Solar Power

A new study shows that it would be possible for the Western power grid to draw 35% of its electricity from wind and solar energy sources by 2017. The Western Wind and Solar Integration Study (WWSIS), released by DOE's National Renewable Energy Laboratory (NREL) on May 20, examines the benefits and challenges of integrating wind power, solar photovoltaic systems, and concentrating solar power onto the grid. The study concludes that while additional infrastructure isn't needed, key operational changes are required to meet this target. The report focused on the power system operated by the WestConnect group of utilities in Arizona, Colorado, Nevada, New Mexico, and Wyoming.

The study found that coordinated operations among utilities across a large geographic area decrease the effect of the variability of wind and solar energy sources. Though wind and solar output vary over time, the study shows that it is operationally possible to accommodate 30% wind and 5% solar energy penetration to the grid. To accomplish such an increase, utilities will have to schedule their generation deliveries, or sales, on a more frequent basis. Currently, generators provide a schedule for a specific amount of power they will provide in the next hour, a process called "hour ahead" scheduling. More frequent scheduling would allow generators to adjust that amount of power based on changes in system conditions, such as increases or decreases in wind or solar generation.

The study also finds that if utilities were to generate as much as 27% of their electricity from wind and solar energy across the Western Interconnection grid, it would lower carbon emissions by 25 to 45%, while decreasing fuel and emissions costs by some 40%, depending on the future price of natural gas. Other key findings from the study include: existing transmission capacity can be more fully utilized to reduce the amount of new transmission that needs to be built; to facilitate the integration of wind and solar energy, coordinating the operations of utilities can provide substantial savings by reducing the need for additional back-up generation, such as natural gas-burning plants; and the use of state-of-the-art wind and solar forecasts in utility operations is essential for cost-effectively integrating these renewable energy sources. The study complements the previously released Eastern Wind Integration and Transmission Study (EWITS), which examines the feasibility of integrating up to 30% wind in the Eastern states. See the NREL press release, the WWSIS Web page, and an article on the EWITS from the January 27 edition of the EERE Network News.

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