Research Helps Texas Renewables Work Better Together

September 6, 2018

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Sunrise at the 2MW CoServ Solar Station in Krugerville, Texas. Photo by Ken Oltmann/CoServ.
Sunrise at the 2MW CoServ Solar Station in Krugerville, Texas. Photo by Ken Oltmann/CoServ.

Saddle up: According to a strategic plan from Texas grid operator Electric Reliability Council of Texas (ERCOT), in the next 14 years the Lone Star State could add approximately 20 gigawatts of utility-scale solar capacity. New National Renewable Energy Laboratory (NREL) research will help ERCOT better manage its solar power and integrate it with the 20 gigawatts of wind capacity already installed in the state, helping Texans better utilize their ample renewable resources.

Since 2016, ERCOT has been using solar power forecasts to estimate the power generated by solar plants installed in its territory and to inform operating plans up to a week in advance. However, those forecasts are not sufficiently accurate; they do not adequately account for an uncertainty inherent in the prediction of solar power generation—clouds. The amount of sunlight available for photovoltaic (PV) plants is dependent on the presence, type, and location of clouds, and accurate predictions that account for their presence are necessary for day-to-day operation needs at ERCOT.

With funding provided by the Energy Department’s Solar Energy Technologies Office, NREL will lead a team of industry leaders and academic researchers to advance state-of-the-art forecasting technologies in predicting solar power generation.

First, the team will use NREL’s algorithms to generate predictions of solar power generation that better account for cloud cover variability and estimate the uncertainty of the solar power forecasts currently used by ERCOT. Then, these predictions will be combined with forecasts for wind power generation and electricity demand, enabling ERCOT to better predict the amount of renewable energy available to meet customer needs.

Second, when ERCOT calculates how much power generation it needs to ensure grid reliability, it will incorporate daily solar generation levels instead of the monthly averages that were previously used. A more accurate prediction of available solar generation enables the utility to more cost-effectively schedule power generation and calculate reserves. NREL will assist ERCOT with developing a methodology that will enable them to dispatch all power generators in a way that optimizes economics and ensures the reliability of the Texas electric grid.

For this research to be useful, it has to be proven in a test environment. As a part of their project, the NREL team will develop a visualization tool that provides operating crews with a sharply defined view and awareness of forecasted solar variability. This solution will be tested in an environment that replicates ERCOT’s operation room, helping to more thoroughly validate the new solution. Finally, the team will organize targeted training sessions on the new system for ERCOT’s operators and improve the tool based on their feedback.

Ultimately, this research collaboration will improve reliability on the Texas Interconnection, helping grid operators make more informed planning decisions for its renewable resources.

Learn more about systems integration research from the Solar Energy Technologies Office.