If the promise of emissions-free fossil fuel-based power generation can become a reality on a commercial scale, one side benefit will be reduced pressure on regional grids to continually reinvent themselves.

Keith Pronske, the CEO of a small privately held California-based firm, Clean Energy Systems (CES), holds out the possibility of both things happening sooner than might be widely recognized.

The Rancho Cordova, Cal.-based CES for more than a decade has been chasing the goal of utility-scale emissions-free fossil-fuel-based electricity generation, which Pronske says is, the logical progression of space technology born in the 1950s and 60s.

CES has perfected a land-based emissions-free power generation system using an oxy-fuel com-bustion process. That means the generation plants use oxygen and various fuels to produce power that results in no atmospheric emissions and water as a byproduct. Carbon dioxide (CO2) is captured and piped for use, ideally in productive oil fields for enhanced oil recovery opera-tions. For the past two years, working with the California Energy Commission (CEC) and others, CES has successfully tested a 5-MW version of its technology in oil fields north of Bakersfield, Calif.

"At the end of those tests, it was concluded that the combustion technology appeared to work quite well," said Rich Dennis, turbine technology manager for the federal Department of Energy (DOE), based in Morgantown W.Va. Since the end of 2005 Dennis has lead a DOE program aimed at designing a CES-like combustor that uses synthetic gas made from coal, including contracting with Siemens to develop special turbines.

While the federal fossil fuel-related research is centered almost entirely on coal, applying the CES technology, to gasified coal constitutes near-zero emissions, but it is not as clean as the project CES is developing in California.

That effort involves a 50-MW natural gas-fired, emissions-free plant that is being planned and designed this year. San Diego-based Sempra Energy has become a full equity owner of CES with a $2.5-million investment and two years ago, Arlington, Va. based AES Corp. took a similar equity position.

Pronske thinks his company's generation plants could impact regional energy infrastructure and integrated resource planning because they add to the viable, global, climate-friendly choices for electricity production, and at the same time they can be built closer to load centers, eliminating the need for additional transmission lines.

"We're real excited about it; the technology has shown a lot of promise," said Dennis, who worked with CES from DOE's perspective in the 2000-02. CES's combustor technology is pretty much perfected, said Dennis, who contrasted this with the high-temperature turbines, which he thinks still face a lot of challenges.

"CES is the only one in the world, that I know of, that is doing this kind of technology. They are the commercial champions of it, and they recognize as well as we do that they need a turbine that will be produced by someone else. They also have the latitude to take the existing machines and use them at lower efficiencies and if you're making electricity with zero emissions you probably can tolerate less efficiency," Dennis said.

The key to CES going fully commercial with utility-scale plants depends on the manufacture of high-temperature turbines. That does not require a technology breakthrough, Pronske says, but rather the engineering to get the job done. And what is in play is somewhat the classic "chicken/egg" dilemma, because until there is more defined market, it is hard to get one of the major turbine makers [General Electric, Siemens, Rolls Royce or Mitsubishi] to commit an engineering team to the task."

Skeptics would counter that the inherently complex contraption is still in a pre-commercial mode. It's a space technology that has yet to fully land on Earth. CES and its supporters disagree, saying it is somewhat the same challenge that gasification faces in which some people will take the view that it is unproven, experimental and unreliable, and yet nations have run their entire energy sectors on gasification for decades.

"This can have a tremendous impact on the grid because we have the ability to locate these plants in developed urban areas where we currently have old power plants, so it's difficult to site new ones because of emissions. You've got plants in the Los Angeles Basin, many of which sit on top of oil fields. These would be ideal for one kind of project" Pronske said [Richard Nemec].