The big black box in the boiler room at the Radisson Blu hotel in Bloomington looks a bit like something out of a science fiction movie. Inside, chemical reactions are turning carbon dioxide into grist for soap-making.

The "CarbinX" machine is part of a CenterPoint Energy pilot program aimed at capturing carbon dioxide and boosting energy efficiency.

"Decarbonization of the gas system is becoming more important to CenterPoint and the state of Minnesota," said Todd Berreman, energy efficiency director at CenterPoint. Indeed, gas utilities are under pressure from regulators and environmental groups to slash CO2 emissions.

"This is a piece of the pie," Berreman said.

A very small piece now, but an intriguing one. The CarbinX machine, developed by Calgary, Alberta-based Clean O2, sucks in flue exhaust from natural gas water heaters and boilers. The machine is stocked with potassium hydroxide, which is transformed into potassium carbonate, an ingredient for soap and other cleaners.

Currently, CarbinX machines capture 25% of the CO2 in flue exhaust, but the company's CEO and founder, Jaeson Cardiff, says a new model that would capture 50% of CO2 emissions is due out as early as this year. He said 100% carbon capture is feasible.

Clean O2's market is commercial buildings, and the company often works closely with utilities to deploy its machines.

Houston-based CenterPoint, Minnesota's largest gas utility, recently launched a pilot program paying for the $25,000 machines. The first of 10 was installed at Guardian Angels, an assisted living center in Elk River. The CarbinX machine at the Radisson Blu was deployed last week.

"We were very interested in the project because of our sustainability culture," said Alberto Abreu, general manager of the Radisson Blu Mall of America. "Hopefully, this will incentivize other hotels to try the unit."

The Radisson Blu brand in the U.S. — along with other Radisson concepts and several chains including Country Inn & Suites — are owned by Maryland-based Choice Hotels International. The company's long reach gives Clean O2 and CenterPoint potential to expand CarbinX technology if the pilot succeeds.

"Getting in with a partner like Radisson Blu is really important to us," Berreman said.

Cardiff said the lodging industry is "particularly interesting" because hotels are natural customers of soap and other cleaning products. "They use a lot of detergents, and we can provide them with something that supports the circular economy."

Cardiff, a plumber and gas fitter by trade, started developing CarbinX technology in 2005 and sold his first commercial machine in 2017. Clean 02 since has sold 42 more machines, which are deployed in Canada, the U.S. and Japan.

Soap-making is a critical part of Clean 02's economic model since it provides revenue for both Cardiff's company and the CarbinX machine's hosts. Potassium carbonate — pearl ash — is collected from the machines and made into soap or other detergents by Clean 02 itself or contract manufacturers.

Part of Clean O2's challenge will be building out an economically efficient soap-making network.

The company is small, generating about $1.6 million in sales last year. Cardiff said Clean 02 is working on an agreement with a major U.S. boiler manufacturing company to make and distribute the CarbinX machine.

The $300,000 cost of CenterPoint's CarbinX pilot project in Minnesota is covered by the utility's state-mandated and ratepayer-funded Conservation Improvement Program. That program is aimed at energy efficiency projects.

The CarbinX machine captures waste heat from furnace and water heater exhaust, recycling it to preheat water flowing into water heaters and conserving gas in the process.

CenterPoint is evaluating whether to expand its CarbinX program via a separate regulatory route dedicated to carbon reduction. That would need approval from the Minnesota Public Utilities Commission.

CO2 releases from furnaces and water heaters are known as Scope 3 emissions and are discharges from end users. CenterPoint's Scope 3 emissions policies have been criticized by As You Sow, a nonprofit group representing two of the company's shareholders.

On their behalf, As You Sow filed a shareholder proposal for CenterPoint's coming annual meeting aimed at getting the company to bolster its Scope 3 policies. CenterPoint recommends its shareholders vote against the resolution, saying its Scope 3 policies are adequate.

Whether CarbinX technology can have a significant effect on reducing C02 emissions is far from clear.

"I think it is an interesting technology," said Joe Dammel, manager director for buildings at Fresh Energy, a St. Paul-based clean energy advocacy group. "But in terms of the scalability and commercial technology potential of [CenterPoint's program], I'd like to wait and see the pilot's results.

Dammel said the best way to cut CO2 emissions from natural gas is to electrify heating.

"The gas that you don't use is a much more effective way of stopping emissions," he said.