Building off a design invented and patented nearly 207 years ago by Robert Stirling, Qnergy’s Free Piston Stirling Engine is revolutionizing the capture of one of the most harmful pollutants out there — methane — and turning it into electricity.
The Ogden, Utah-based company took an engine first used to pump water into a quarry in 1818, retooled it with proprietary technology that is now deployed in a dozen oil and gas fields in eastern Utah, with more operating in Wyoming and 500 that are scattered in the Marcellus formation in the United States, one of the largest natural gas fields in the world.
“There is a high concentration of methane in natural gas,” said Steve Maughan, vice president of engineering for Qnergy.
In fact, natural gas is made up of 70% to 90% methane, which after carbon dioxide, is the second most prevalent greenhouse gas, accounting for 20% of global emissions, according to the U.S. Environmental Protection Agency.
Coupled with the Qnergy’s Compressed Air Pneumatics system, the Stirling generator can take what would be harmful methane emissions at gas well sites and turn them into harmless compressed air. These power generators can also transform emissions from landfills and pig farms.
Methane mitigation is especially important in the oil and gas industry, since the Biden administration is clamping down on emissions and issuing fines for producers who emit at certain levels.
Simplicity in action
The beauty of the Free Piston Stirling Engine by Qnergy is that it does not use any friction to turn an energy source into electricity and it lacks external combustion, Maughan said.
This allows the generator to be essentially maintenance free, absent an annual routine inspection.
“They can operate 24 hours a day, seven days a week for a year,” he said.
“In a combustion engine, every six weeks you have to change the oil,” he said. “There’s no reason to lubricate the (Stirling) engine.”
The engines are designed for 80,000 hours of continuation operation and, so far, the worldwide deployment of these have accumulated 10 million hours of engine operation.
The company has one of its generators in a remote spot in Utah’s Nine Mile Canyon where it is used to power the energy necessary to provide cathodic protection for natural gas pipelines.
Cathodic protection prevents corrosion on buried metal pipelines, storage tanks and oil well casings.
In the case at Nine Mile Canyon, the generator is producing direct current electricity to provide that protection, eliminating the need for a power pole.
From Nine Mile Canyon to Idaho National Laboratory
A Qnergy engineer teamed up with project lead Yasir Arafat at Idaho National Laboratory to develop the right kind of Stirling engine to power MARVEL, a sedan-sized nuclear microreactor that may come online as early as next year.
At a media event earlier this year, Arafat explained the importance of MARVEL.
“The way I think about the globe is that 50% of the world’s population lives on 1% of the footprint on this earth. With microreactors, you can make uninhabitable places livable and, again, you can refine water, you get energy. ... It can make opportunities for people to live. We are looking at Mars and other planets for colonization, but on Earth we have a lot of uninhabitable places we can open up.”
Qnergy has one of its generators in a remote location in Alaska and has worked with the National Oceanic and Atmospheric Administration to install power to run weather stations.
Maughan said while other companies are starting to enter the field, they remain the leader. Even though it is only a two-week production process, their backlog for orders runs into August.
The company employs a bevy of engineers in all matters of disciplines and has a business development office on the campus of MIT.
“There’s no one else doing what we are doing,” Maughan said.
Correction: A previous version of this story identified Steve Maughan’s last name as Graham in subsequent references.