The buzzed-about summer series from Netflix “Stranger Things” depicts a fictional and highly secretive Department of Energy national laboratory unleashing a monster from another dimension on an unsuspecting Indiana town. It caused a lot of stress. But as my DOE colleague blogged, national laboratory researchers aren’t actually evil. In fact, a lot of us at the National Renewable Energy Laboratory (NREL) are working to reduce stress for power system operators and the power systems themselves as we shift to higher penetrations of wind and solar generation.
The key to managing stress in power systems is to anticipate and plan ahead. As power systems shift away from coal and to more natural gas, wind, and solar; operators and planners want to know how to predict the conditions they might face in the future.
At NREL, we think about futures with higher penetrations of wind and solar every day. Sometimes we think about what resources will be built, and where they will be built. Other days we’re thinking about how wind and solar power forecasts can be better incorporated into system operations. And in our integration studies, we explore the day-to-day challenges that could be expected in a future where wind and solar serve nearly 30 percent of annual load.
The Eastern Renewable Generation Integration Study (ERGIS) is our most recent attempt to explore what the future power system in the Eastern Interconnection could look like, and how it might operate on a daily basis. ERGIS builds on the lessons learned in previous integration studies, like the Western Wind and Solar Integration Study and Eastern Wind Integration and Transmission Study. ERGIS is the most detailed integration study we’ve done to date. We used the Regional Energy Deployment System (ReEDS) for generation capacity expansion/retirement, adopted transmission expansions from the Eastern Interconnection Planning Collaborative, and solved a mixed-integer optimization on a 60,000-node model of the Eastern Interconnection and Québec Interconnection. It took weeks to solve on our High-Performance Computer, Peregrine, and resulted in some big data in our solution files. To understand what wind and solar were doing to the system and what stressful conditions might look like for system operators in the future, we needed to come up with some new tools, and new ways to understand the stranger things that were happening in the data.
One of the tools we created to better understand the data is called the Multi-Area Grid Metric Analyzer (MAGMA). You can download the code from our GitHub repository. This tool helped us to analyze the regional and system wide impacts of wind and solar across time and space. We used it to systematically investigate traditionally challenging periods of system operations, as well as a few new challenges that wind and solar might present. To make the package, we refined a collection of scripts and programs that were developed in ERGIS and other projects to create a single resource for our data analysis. We found it decreased the time it took us to review our results, allowing us to dive deeper into questions we have not been able to investigate in the past. The tool will be released to the public, and we hope you can find a use for it in your projects too.
One of the things MAGMA helped us do was create visualizations of various system conditions. The first place we looked for system stress was based on historically challenging conditions, like peak load. We analyzed the top three load weeks for the system, and chose one period to look at in detail for the ERGIS final report. Here are two examples of commitment and dispatch plots that helped us compare results across the four study scenarios.
We also used the tools to explore some emerging concerns for system operators. We all know about the California duck curve, but what might an Eastern Interconnection “duck” look like?
Before ERGIS, no one had data to look at large-scale solar adoption in the Eastern Interconnection, and no one had ever seen what the dispatch looked like on the largest power system in the world with 120 s (GW) of solar and 80 GW of wind … at the same time.
In our analysis, we found several duck-shaped net-load profiles, especially in the spring and the fall. One of them, from our 10 percent solar and 20 percent wind case, the RTx30, is seen in this dispatch stack, the one with nearly 200 GW of wind and solar generation. This period stands out among other duck-curve plots because there are actually two, back-to-back duck shaped net-load ramps on May 12. The first is driven by wind and occurs after midnight, the second occurs around noon and is driven by both high solar and wind.
We also wanted to explore the “stranger things” in power system operations that can result from forecast errors and net load ramping. We found a period in November 2026 that combined three challenging conditions; a 60-GW forecast error corresponded with the down ramp from 100 GW of solar and a 40-GW increase in load, all in the span of six hours. To hear the full story on this strange set of operating conditions, you’ll have to attend the UVIG Forecasting Workshop Sept. 28 to 29 where Josh Novacheck, who is decidedly NOT evil, will tell you all about this video and follow-up work from ERGIS on stressful system conditions.
Aaron Bloom
Manager
National Renewable Energy Laboratory