NREL study looks at how eastern grid could accommodate 30% renewables

A recent study from the Department of Energy (DOE) National Renewable Energy Laboratory (NREL) used high-performance computing capabilities and other tools to examine how the power grid of the eastern United States could operationally accommodate 30% annual penetration of wind and solar.

Whereas previous studies have investigated operations in one-hour intervals, the NREL study released Aug. 31 analyzed a year of operations at 5-minute intervals, the same real-time interval used by grid operators for scheduling resources.

“By modeling the power system in depth and detail, NREL has helped reset the conversation about how far we can go operationally with wind and solar in one of the largest power systems in the world," said Charlton Clark, a DOE program manager for the study.

"Releasing the production cost model, underlying data, and visualization tools alongside the final report reflects our commitment to giving power system planners, operators, regulators, and others the tools to anticipate and plan for operational and other important changes that may be needed in some cleaner energy futures," Clark said in a news release.

For the study, NREL produced a high-resolution model of the entire Eastern Interconnection, including Canada, an important power trading partner with the United States. NREL modeled more than 5,600 electricity generators and more than 60,000 transmission lines in a power system that spans from Florida to Maine and portions of Canada and as far west as New Mexico.

The “Eastern Renewable Generation Integration Study (ERGIS) considered four hypothetical scenarios to analyze how the Eastern Interconnection might function in 2026, when the power system could have significantly less power generation from fossil fuels.

The scenarios vary according to how wind, solar, and natural gas are used to replace the fossil fuel generators. The scenarios also differ according to the amount of new transmission lines that are assumed. Simulations occur in a modeling framework that mirrors the security constrained unit commitment (SCUC) and economic dispatch (SCED) process used by system operators.

The study suggests that traditional power sources like coal, natural gas and hydroelectric facilities would likely run for shorter periods of time as wind and solar meet more of the demand.

For example, wind and solar generation result in a 30% reduction in generation and commitment from coal and natural gas plants in the high wind and solar scenarios.

Regulatory changes, market design innovation, and flexible operating procedures are important to achieving higher levels of wind and solar, NREL said in the study.

Looking at a year of operations at a five-minute level, ERGIS shows that the power system can meet loads with variable resources-like wind and solar-in a variety of extreme conditions.

But technical feasibility depends on other transmission and generation operators providing the necessary ramping, energy, and capacity services; wholesale market design changes; and various capital expenditures.

Over the baseline scenario, CO2 emissions were reduced by up to 33% annually in our high wind and solar scenarios.

NREL developed new modeling and analytical approaches that were executed using Peregrine, the lab’s ultra-efficient supercomputer. Peregrine has a peak performance of 2.25 petaflops (2.25 million billion calculations per second).

About Wayne Barber 4201 Articles
Wayne Barber, Chief Analyst for the GenerationHub, has been covering power generation, energy and natural resources issues at national publications for more than 20 years. Prior to joining PennWell he was editor of Generation Markets Week at SNL Financial for nine years. He has also worked as a business journalist at both McGraw-Hill and Financial Times Energy. Wayne also worked as a newspaper reporter for several years. During his career has visited nuclear reactors and coal mines as well as coal and natural gas power plants. Wayne can be reached at