NREL Study Shows Power Grid can Accommodate Large
Increase in Wind and Solar Generation
NREL - May 20, 2010
The National Renewable Energy Laboratory (NREL) today released an
initial study assessing the operational impacts and economics of
increased contributions from wind and solar energy producers on the
power grid. The Western Wind and Solar Integration Study examines the
benefits and challenges of integrating enough wind and solar energy
capacity into the grid to produce 35 percent of its electricity by 2017.
The study finds that this target is technically feasible and does not
necessitate extensive additional infrastructure, but does require key
changes to current operational practice. The results offer a first look
at the issue of adding significant amount of variable renewable energy
in the West and will help utilities across the region plan how to ramp
up their production of renewable energy as they incorporate more wind
and solar energy plants into the power grid.
“If key changes can be made to standard operating procedures, our
research shows that large amounts of wind and solar can be incorporated
onto the grid without a lot of backup generation,” said Dr. Debra Lew,
NREL project manager for the study. “When you coordinate the operations
between utilities across a large geographic area, you decrease the
effect of the variability of wind and solar energy sources, mitigating
the unpredictability of Mother Nature.”
The study focuses on the operational impacts of wind, photovoltaics, and
concentrating solar power on the power system operated by the
WestConnect group of utilities in the mountain and southwest states.
WestConnect is a group of transmission providers, which includes Arizona
Public Service, El Paso Electric Co., NV Energy, Public Service of New
Mexico, Salt River Project, Tri-State Generation and Transmission
Cooperative, Tucson Electric Power, Western Area Power Administration,
and Xcel Energy. Though wind and solar output vary over time, the
technical analysis performed in this study shows that it is
operationally possible to accommodate 30 percent wind and 5 percent
solar energy penetration. To accomplish such an increase, utilities will
have to substantially increase their coordination of operations over
wider geographic areas and 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. 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 generate 27 percent of their
electricity from wind and solar energy across the Western
Interconnection grid, it would lower carbon emissions by 25 to 45
percent. It would also decrease fuel and emissions costs by 40 percent,
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.
• Use of wind and solar forecasts in utility operations to predict when
and where it will be windy and sunny is essential for cost-effectively
integrating these renewable energy sources.
The study was undertaken by a team of wind, solar and power systems
experts across both the private and public sectors. The study
complements the recently released Eastern Wind Integration and
Transmission Study, which examines the feasibility of integrating up to
30 percent wind in the eastern states.
The report released today is an important first step in assessing the
impact of solar and wind energy on the electrical grid. Under the
American Recovery and Reinvestment Act, the Department of Energy is
investing more than $26 million to further study the Western
transmission interconnection, which will help states, utilities, and
grid operators prepare for future growth in energy demand, renewable
energy resources, and Smart Grid technologies.
The study can be downloaded at http://www.nrel.gov/wwsis. A media
webinar will be held on May 20, 2010. For details, please contact
Richard Sawyers at rsawyers@kearnswest.com.
NREL is DOE’s primary national laboratory for renewable energy and
energy efficiency research and development. NREL is operated by DOE by
The Alliance for Sustainable Energy, LLC.
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