Wind, solar could replace coal power in Texas

Texas could be a model for the nation on how effectively coal is replaced by wind and solar for the state’s energy needs, while meeting environmental goals, according to new research from Rice University engineers.

The new work led by Environmental Engineer Daniel Cohan and Senior Informatics Major Richard Morse of Rice George R. Brown School of Engineering uses optimization modeling to identify the least costly combinations of proposed wind and solar projects with the potential to replace coal generation in Texas.

As the authors say in the paper that is in the journal Renewable energies: wind, water and solar“Simply put, it’s not always windy and not always sunny, but it’s almost always windy or sunny somewhere in Texas.”

Cohan said this could allow wind and solar to replace almost any coal outlet, especially if wind and solar projects are located in places that provide complementary output. The new paper builds on a 2018 study from his lab.

“This paper is really about how we can get rid of coal as quickly as possible,” said Cohan, an associate professor of civil engineering and environmental engineering. “Texas still burns more coal and emits more sulfur dioxide and other pollutants than any other state. Even though a transition is inevitable, it is urgent that we move out of coal as soon as possible to improve air quality and health. ”

“The energy cleanup we use to empower society is one of the most important things we need to do,” said Morse, who won the Malcolm Verdict Memorial Poster Contest at the Texas Energy Summit in 2020 for his work on Project won. “Professor Cohan announced it as a mathematical project, and that’s my background, so being able to help with a clean energy integration project was very interesting to me.”

Several large Texas coal plants closed in 2018, and most of the remaining plants operated well below capacity, including in the middle of the fall during the February 202 freeze. The team’s research found that only one-third of the wind – and solar projects already proposed to the Texas Electrical Reliability Council by June 2020 will replace almost all of the state’s coal generation. Since June 2020, dozens of these projects have been built, and the queue of proposed solar projects has doubled.

The key to success for wind and sun is an extension of transmission lines that connect the windiest and sunniest parts of the state with the cities.

“In Texas, this is the largest bottleneck that slows down the growth of wind and sun,” Cohan said. “The bipartisan infrastructure bill passed last year is a good start, but does not have nearly enough funding for the transmission. Also, by not connecting it to other grids, Texas has missed opportunities for excess wind and solar energy. to sell to other states. “.

Cohan notes that natural gas will continue to be critical to Texas’ electrical reliability in the short term, especially as ERCOT works to recover from the 2021 freeze. However, complementary seating of wind and solar farms could reduce the need for natural gas and storage and eliminate the need for coal, he said. The study shows that wind power from West Texas tends to peak overnight, while South Texas wind gusts with sea breezes in the summer afternoon and evening. Together with the sun during the day, these complementary sources can cover most but not all hours of the year.

“Even with complementary seating, there will still be hours when the sun is not shining and the wind is not blowing,” Cohan said. “Historically, the main challenge was summer afternoons when air conditioners were running at full height, and sometimes deep freezing. Solar and coastal winds work well during the summer peaks, but can have lull on some evenings if we need something else to shoot. in the.”

He said eliminating coal from the Texas grid is just a matter of time. “I think none of the power companies want to run long-term coal plants,” Cohan said. “They are dirtier and more expensive to operate than building zero-solar wind and solar projects, and most utility companies now have plans to achieve non-zero carbon emissions by 2050, if not earlier.

“Maybe that’s why they have not invested in upgrades to their coal plants, many of which are more than 40 years old and not very efficient,” he said.