The first reaction is always the same: It’s too good to be true.

The disbelief is directed at a next-generation power plant under development in Durham by NET Power. Its backers say their machine won’t emit a particle of pollution.

The emissions-free concept exists only on paper today, but a key mechanical component is getting readied for testing in about four months. It would have to elevate the pressure at which natural gas is burned by a factor of several times, a thermodynamic feat that has only been achieved in the aerospace industry but is limited to computer simulations in power plants.

Many remain skeptical, saying that a zero-emissions power plant is a marketing slogan wrapped around a physical impossibility.

Still, NET Power has a star-studded cast lined up behind the project: Designers and engineers from Japan’s Toshiba technology/electronics conglomerate; Chicago-based Exelon Corp., a major utility company that plans to test and operate these power plants; and The Shaw Group, a Baton Rouge global engineering and construction firm with 1,100 employees in Charlotte.

“We’re competing with solar in terms of emissions,” said NET Power executive Bill Brown, who teaches law at Duke University and spent years financing deals on Wall Street. “The next power plant actually has no smokestack.”

The power plant is one of several high-tech projects being developed by 8 Rivers Capital, a privately-funded Durham high-technology commercialization firm. Brown co-founded 8 Rivers in 2008 with fellow Massachusetts Institute of Technology alum and chemist Miles Palmer, a onetime U.S. Air Force test flight engineer who trained for astronaut duty with NASA. They have recruited principals and advisers with credentials from the Ivy League, Wall Street and U.S. Department of Energy.

One of the NET Power advisors is Joseph Strakey, a retired chief technology officer at the DOE’s National Energy Technology Laboratory in Pittsburgh.

“This is the power plant of the future,” Strakey said. “This is real. This isn’t just some crazy inventor who came up with something.”

NET Power’s goal is to create a super-efficient power plant that burns gas in a pure oxygen chamber and whose only byproducts are water and carbon dioxide, or CO2. The carbon dioxide is seen as an added source of revenue, with potential in various markets, such as advanced oil recovery, where oil is dislodged through underground gas injection. Or it could some day be pumped deep underground as waste, Strakey said.

Power plants today simply release CO2 into the atmosphere, and are considered by climate change advocates as one of the main causes of man-made global warming. Carbon dioxide can be removed from power plant emissions, but the energy-intensive process is so expensive that power companies such as Raleigh-based Progress Energy, which was acquired by Duke Energy in July, had abandoned coal-burning power for fear that CO2 emissions will one day be regulated.

Natural gas burners are much cleaner than coal, emitting half the carbon dioxide and a fraction of other pollutants that are released by incinerating coal. The NET Power design traps the CO2 without degrading energy efficiency, and in the process eliminates other emissions, such as nitrous oxides and mercury, a neurotoxin to children.

In its first iteration, the NET Power facility would burn natural gas. In the future, it could be modified to burn gas extracted from coal through the process of gasification.

Skeptics are bound to question the way the project is being described as emissions-free, especially in the wake of the U.S. Supreme Court’s 2007 decision that CO2 from automobiles is a pollutant.

Claims questioned

Bruce Nilles, director of the Beyond Coal Campaign for the Sierra Club, dismisses any such clean-energy claims for fossil fuel industries as “ridiculous.”

“CO2 is emissions,” Nilles said. “It meets the definition of pollution under the Clean Air Act.”

Nilles’ chief objection, however, is that natural gas has to be brought out of the ground through fracking or some other means, while coal-mining methods include mountain-top removal. That makes NET Power dependent on fossil fuels that are environmentally disruptive, Nilles said.

Strakey said he didn’t believe the NET Power concept was physically possible when the Durham company in 2010 asked the National Energy Technology Laboratory to independently verify the results through software simulations.

His skepticism was based on professional experience in federal research to improve the efficiency of power plants. It took NETL a decade to develop a super-efficient natural gas turbine that is less efficient than NET Power’s design because it doesn’t trap carbon dioxide. “It took 10 years to develop,” Strakey said, “and we spent millions of dollars doing it.”

The more efficient the plant, the less fuel it needs to produce electricity. The concept is equivalent to an automobile that matches the world’s highest gasoline mileage rating and as a bonus doesn’t need an exhaust pipe because it spews no waste.

The Allam Cycle

Shaw is investing $50.4 million in the project and will acquire up to a 50 percent stake in NET Power. Toshiba is designing NET Power’s high-pressure combustor and turbine, the key elements that must be specially developed for this project. The new components will be field-tested at a power plant to be built by Exelon, Toshiba and The Shaw Group outside of North Carolina.

The combustor is to be tested in December or January. Exeleon will then test the entire system in a 25-megawatt power plant in 2014. The final phase is to build a 250-megawatt NET Power plant in 2017, which would be a small but industrial-scale facility.

The combustion technology is named the Allam Cycle, after inventor Rodney Allam, a British chemical engineer who co-authored the global warming report by the Intergovernmental Panel on Climate Change.

“We just have not had in our universe something that burns this mixture of gas at this pressure,” Brown said.

8 Rivers was introduced to Allam through the firm’s MIT connections. Brown flew to London in 2009 to meet with the inventor of the technology the American investors coveted. Brown and Allam spent the afternoon talking in an upper-level Morgan Stanley suite overlooking London’s financial district.

“The first reaction is always, it’s too good to be true,” Palmer said. “The truth only comes out when you study it in exquisite detail.”