Most everyone has encountered carbon dioxide in its gas and solid forms. Gaseous carbon dioxide leaves our lungs when we exhale, and solid carbon dioxide, or dry ice, is often the secret ingredient in a spooky Halloween punch bowl.
But under certain high-temperature, high-pressure conditions, using carbon dioxide in power generators in place of traditional mediums like steam or air can help power systems run more efficiently, engineers at Southwest Research Institute said Monday. This can save fuel and money and reduce greenhouse gas emissions.
As part of a six-year effort to further develop this technology, construction will begin this month at Southwest Research’s West San Antonio campus on a 10-megawatt demonstration power plant. There, a turbine the size of a desk will generate enough electricity to power 10,000 homes.
Southwest Research, the nonprofit center for research and development, is working with the Gas Technology Institute and General Electric on the pilot project, which engineers hope will show the technology is commercially viable.
“It exemplifies part of what is truly great about our institute: commitment to improving our world through innovation,” Southwest Research President and CEO Adam Hamilton said at an event Monday.
Attendees included elected officials such as U.S. Rep. Will Hurd (R-Texas), Texas Secretary of State Rolando Pablos, and State Sen. José Menéndez (D-San Antonio).
The $119 million pilot plant is receiving up to $84 million in funding from the U.S. Department of Energy, which has engaged the institute in more than 20 projects involving similar. On Monday, Southwest Research engineer Jeff Moore led a tour of the laboratory where the institute’s staff have fine-tuned equipment so it could handle what researchers call supercritical carbon dioxide.
“Supercritical” refers to a fluid that’s in the throes of an identity crisis. Under the right heat and pressure conditions, carbon dioxide can behave like a gas, even though it has the density of a liquid.
That means small changes in temperature and pressure bring huge changes in density, something engineers can harness in the power-generation process. Using supercritical carbon dioxide can make power systems 6 to 10 percent more efficient, said senior research engineer Aaron McClung, who leads the project team.
“We’re circulating carbon dioxide throughout the system, and that allows us to tweak some of the properties on the power side,” McClung said. “We can optimize things here, change things there, to get higher efficiencies.”
Department of Energy Assistant Secretary Steven Winberg, a former vice president at Consol Energy, called the use of supercritical carbon dioxide a “huge technology advance.”
“It can be used on coal,” he said. “It can be used on natural gas, it can be used on nuclear, and it can be used on … large solar collection facilities. It is truly cross-cutting across many of our energy resources.”
San Antonio Mayor Ron Nirenberg said the plant will be a “game-changing pilot that demonstrates first-of-its-kind technology developed right here in our city.”
“Most power plants are aging and inefficient,” Nirenberg said. “They burn large amounts of fossil fuels, creating significant greenhouse gas emissions that are harmful to the environment. … Southwest Research Institute, the Gas Technology Institute, and [General Electric] are helping the industry take a leap forward to reduce cost and emissions.”
Southwest Research staff expect construction on the plant to be complete in April 2020.