Advancing Best Practices: Wind/Solar integration

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Advanced Energy Economy Institute and The Brattle Group for their June 2015 case study, Integrating Renewable Energy into the Electricity Grid, which explores how Electric Reliability Council of Texas (ERCOT) and Xcel Energy Colorado are integrating variable renewable energy (primarily wind power) into their regional grids.

ERCOT and Xcel Energy Colorado already manage large volumes of wind power while matching generation with demand in real time-an ironclad physical law of electricity grids. To allow continued growth of renewable power as envisioned under the federal Clean Power Plan and state renewable power mandates, other grid operators will have to contend with the same challenges that these two grid operators are facing successfully.

At 12.5 GW of wind turbine capacity, ERCOT is the biggest user of wind energy in North America; and Xcel Energy Colorado meets close to 20% of its average load with wind energy and experiences periods when wind energy is meeting more than half of demand, according to the report.

The two grid operators are managing the variability of wind power with "well-established and widely available methods and technologies," including: Ancillary services provided by flexible gas turbines, demand response and storage; the evolving reliability capabilities of renewable generators; and expansion of transmission infrastructure.

While ERCOT and Xcel Energy Colorado demonstrate what's possible with existing methods, authors Jürgen Weiss and Bruce Tsuchida aver that for renewable power to keep growing, "continued significant planning and effort, as well as investment [will be needed] in transmission infrastructure to bring electricity from renewable resource rich locations to load centers, and in distribution infrastructure."

"Bringing additional renewable resources to market will thus likely be an important additional driver of planning and building a 21st century grid, which is also driven by changes on the demand side … (including distributed generation, but also new sources of demand and options for demand-side flexibility), changing population densities, the desire to further increase inter-regional interconnections, cybersecurity concerns, the aging of existing transmission and distribution infrastructure, etc."

ERCOT is the independent system operator for Texas, managing the flow of electricity for about 24 million customers. Brattle is a research and consulting firm specializing in electric power, oil and gas, healthcare, financial services, telecom and transportation.