This article is part of Upstart, a series about young companies harnessing new science and technology.

LA PORTE, TEXAS — It wasn’t like it is in the movies. Nobody pulled down a big switch on the wall, producing a satisfying “thunk” and crackle of electricity. Instead, one evening last November, a shift supervisor for NET Power, a clean-energy technology company, clicked a mouse several times in a control room set in a double-wide trailer. With the last click, the company’s generator synchronized with the Texas grid, a major step toward providing power to homes and businesses. Twenty-seven minutes later, the supervisor cut off the connection.

It might not sound like much, but that brief display at this demonstration plant — with a fraction of the capacity of a full-scale facility — showed that a novel way of generating electricity that burns natural gas but doesn’t generate the same greenhouse gas emissions as fossil fuels, could play nicely with the nation’s power grid.

Cam Hosie, who heads 8 Rivers, the earliest shareholder in NET Power, said he was monitoring the test that evening on his laptop. When the plant synced up, he recalled, “I cried.”

It was a milestone for NET Power, which had been working toward the technology for 12 years. That synchronization — a tricky feat of matching the grid’s frequency and other characteristics — opened an enormous flow of interest, as companies looking for a cleaner way to generate power began seeking to license NET Power’s technology. Potential customers have announced plans for new plants around the world, including in the United States, Canada, Germany and Britain.

“If this were to become commercially deployable, it could play a key role, among others, in our ability to meet net-zero targets in the U.S., as well as globally,” said Carrie Jenks, executive director of Harvard Law School’s environmental and energy law program.

Most electrical plants boil water by burning coal or natural gas, or through nuclear fission; the resulting steam then spins a turbine. The burning of those fossil fuels yields greenhouse gases, the primary culprits in climate change. Scientists warn that if we cannot stop those emissions, increasingly dire disasters lie ahead.

Renewable energy (like solar, wind and geothermal power) has grown tremendously as its price has dropped. But many experts suggest that the grid will still need electricity sources that can be started up quickly — what the trade calls “dispatchable” power — to fill gaps in the supply of sunshine and wind. And while some researchers have suggested that the electric grid can be built completely on renewable energy and storage, Professor Jenks said, “I think fossil will continue to be in our energy system in the near future.” And so “you need a host of solutions for us to be able to keep moving on the path we need to go now. We don’t yet know what the silver bullet is — and I doubt we’ll ever find a silver bullet,” she said.

That’s where fans of NET Power say the company can make a difference: its technology burns natural gas without causing the biggest problems fossil fuels typically do. It combusts a combination of natural gas and oxygen inside a circulating stream of high-temperature carbon dioxide under tremendous pressure. The resulting carbon dioxide drives the turbine in a form known as a supercritical fluid.

In other power plants, capturing carbon dioxide means adding separate equipment that draws considerable energy. NET Power’s system captures the carbon dioxide it creates as part of its cycle, not as an add-on. The excess carbon dioxide can then be drawn off and stored underground or used in other industrial processes. The plant’s operations produce none of the health-damaging particulates, or the smog-producing gases like oxides of nitrogen and sodium, that coal plants spew.

Its only other byproduct? Water.

With commercial success, NET Power believes it will meaningfully reduce global carbon emissions, said Ron DeGregorio, the company’s chief executive. Many potential customers could still opt for coal power, but “bring this credibly to market, and this changes the world.”

The company licenses its technology to its customers, and its partners and investors will build and operate the plants. They include oil giant Occidental Petroleum, which is making a big bet on carbon capture; Constellation, which runs power plants; and Baker Hughes, which manufactures the kind of precision equipment the process requires. That kind of investment, said Rick Callahan, the president of Low Carbon Ventures, a subsidiary of Occidental, “demonstrates that people are putting their money where their mouth is with this project.”

The technology, like any power-generating equipment, can be applied in a number of ways, including producing power for industrial processes. Potential customers are being imaginative. One iteration of the process, planned by the energy company TES, founded in Belgium, proposes to incorporate NET Power technology in a complex chain of energy storage and generation as a way to provide hydrogen-based power. “The NET Power technology is a perfect fit” for the proposed system, said Jens Schmidt, chief technology officer for TES.

Another project proposed in Louisiana would use NET Power’s technology to produce various products, including hydrogen, oxygen and nitrogen. Known as G2 Net-Zero, it would also include an export terminal for liquefied natural gas, or L.N.G. Charles E. Roemer IV, the company’s chairman, said that while many L.N.G. export terminals were planned or under construction in coastal Louisiana, building a cleaner alternative could create a new paradigm.

The technology has spawned criticisms, particularly of its reliance on methane infrastructure and of the present-day limitations of carbon storage. Many environmentalists oppose L.N.G. terminals, in large part because they extend the use of fossil fuels; the Sierra Club recently targeted those planned for Cameron, in Southwest Louisiana, including G2 Net-Zero, arguing that they will cause grave environmental damage to the area.

“As long as a power plant is being powered by methane gas, it will continue to harm our climate and communities,” said Jeremy Fisher, senior adviser for strategic research and development for the Sierra Club. “This technology would do nothing to protect families living with pollution from fracking wells or next to dangerous gas pipelines, and it would continue to allow for the massive — and often undercounted — amount of climate-warming methane leaked from wellheads, pipelines and plants.”

Mr. Roemer referred to research showing that proper monitoring and quick action could reduce methane leaks greatly and said that he would work with natural gas suppliers that were “committed to the lowering of emissions.” As for exporting L.N.G. to be burned elsewhere, he said that someone receiving his L.N.G. could burn it in another NET Power plant and avoid greenhouse gas emissions. “I’m going to sell my product to people who are committed to the same things I’m committed to,” he said.

“The problem we’re trying to solve is abundant, clean affordable energy,” Mr. Roemer said. “I don’t see how you could be against what I’m doing.”

If, through regulation, nations make it profitable to capture carbon dioxide and stow it, technologies like NET Power’s will become even more attractive. Yet while the Intergovernmental Panel on Climate Change has repeatedly cited carbon capture and storage as part of the solution to climate change, the details have yet to be worked out — and many in the climate science community frame the technology as an excuse to keep burning fossil fuels, not a good-faith effort to decarbonize.

“What do you do with that CO2?” asked Michael Mann, a climate scientist at Penn State University. “If it’s used to enhance oil recovery, it’s still contributing to the problems. If it’s buried, how safely and permanently is it buried?”

Supporters of the technology note that solar and wind power looked like long shots before government incentives helped refine the technologies and drive costs down. Virginia Burkett, a leading scientist at the United States Geological Survey, said that carbon sequestration in deep geological formations was a “proven technology” and noted that the National Academies of Science called it ready for large-scale deployment” in 2019.

Julio Friedmann, an expert on carbon-removal technologies, called NET Power’s technology “an incredibly elegant solution to a difficult problem.” However, Dr. Friedmann, who has served as an adviser to the company, said that success on a commercial scale was not certain.

“I’ve had many discussions with physicists who say, ‘The physics is settled; the rest is just engineering.’ Well, the engineering is really hard. In theory, there’s no difference between theory and practice. In practice, there is,” he said. “It is still possible that they will fail — but I don’t think so.”