Can power-plant emissions offer an alternative to fossil fuels?

By Dan Rafter

Potential. That’s the word Raymond Hobbs, senior consulting engineer with Arizona Public Service Company, the largest public utility in Arizona, uses when describing the generated-energy project currently running at the Redhawk Power Plant near Phoenix.

The project—which uses carbon-dioxide emissions and algae fields to produce enough onsite energy to power a van used by employees of the power plant—has attracted the attention of the energy community. Platts, a provider of news, analytical services, and conferences centering on the energy and metal industries, late last year honored both Arizona Public Service Co. and Cambridge, MA–based GreenFuel Technologies Corp., the developer that has partnered with the utility on the project, with one of its most prestigious awards.

Under the project, which started in 2005 and continues today, Arizona Public Service Co. is trapping the carbon-dioxide emissions from its Redhawk Power Plant, located about 50 miles west of Phoenix. Workers are then transferring the emissions to a nearby greenhouse-type structure filled with containers of naturally occurring algae. Workers harvest the algae, once enough of it has grown after it consumes the plant’s carbon dioxide, and turn its starches into ethanol and its lipids into biodiesel. These fuels power a Ford E-350 passenger van that ferries employees across the power plant.

Hobbs, though, sees even greater potential. He sees a future where carbon-dioxide emissions from power plants, such as Redhawk, are used to provide much-needed relief from the US’s reliance on other fossil fuels.

“If this proves out, if this in the long run proves to be economically feasible, the carbon-dioxide emissions just from power plants alone can be an enormous source of fuel,” Hobbs says. “You can take the amount of Btus going into power plants from fossil fuels, and move that carbon into the fuel of your choice. It would have a huge impact if this was something we could do on a large scale.”

It’s little wonder that Hobbs, and other observers, are excited about the Redhawk project. The emissions-to-biofuels project addresses two important issues that the US now faces: If replicated on a large-scale basis, the project would be one way to reduce greenhouse-gas emissions at power plants. It would also produce more domestic sources of alternative fuels for automobiles and power plants.

Officials with GreenFuel Technologies, a developer of systems used to recycle carbon-dioxide streams from power and manufacturing plant flue gases to produce biofuels, refer to the vast potential of the experiment when they say it is, theoretically, the first step in creating a self-sustaining renewable energy system for producing electricity.

The relatively small project at Redhawk, of course, would have to be expanded significantly to achieve this far-from-modest goal. But officials with GreenFuel say that they are committed to helping power and manufacturing plants take the steps necessary to get closer to this goal.

“The Redhawk project marks the first time ever that algae biomass, created onsite by direct connection to a commercial power plant, has been successfully converted to both transportation-grade biodiesel and ethanol,” says Cary Bullock, chief executive officer of GreenFuel.

An Economic Decision
Isaac Berzin, chief technology officer of GreenFuel Technologies Corp., knows all about the potential that algae has for generating biofuels. He’s the one who’s primarily responsible for GreenFuel’s patented approach to propagating algae on an industrial scale.

It was due in large part to him, then, that Arizona Public Service Co. decided to turn its algae into biodiesel ethanol, a liquid fuel, rather than a type of biogas. It’s far less costly to create liquid biofuels than it is to create their gaseous counterparts, Berzin says.

“If you compare the dollars to pounds on an economic matrix, you’ll see quite clearly that creating liquid biofuel is far more efficient and cost-effective,” Berzin says. “It’s more difficult to do it cheaply enough if you’re aiming for biogas.”

The project uses GreenFuel’s Emissions-to-Biofuels algae bioreactor system connected to Arizona Public Service’s 1,040-MW Redhawk power plant located in Arlington, AZ. This process allows GreenFuel to create a carbon-rich algal biomass, that has enough quality and concentration of oils and starch content, to be easily converted into transportation-grade biodiesel and ethanol.

This is not the only time GreenFuel has tackled such a project. The company’s Emissions-to-Biofuels technology relies on naturally occurring algae to recycle carbon dioxide from the stack gases of power plants and other commercial sources of continuous carbon dioxide emissions.

The Redhawk plant features specially designed pipes that capture and transport the carbon-dioxide emissions. Workers then transfer this gas to containers holding hungry algae. Like all plants, algae divide and grow through photosynthesis. When sunlight is present, the algae consume carbon dioxide. Officials with GreenFuel estimate that, through this process, algae can consume as much as 80% of carbon-dioxide emissions during the daytime hours at a typical natural-gas-fired power plant.

So far, Arizona Public Service has used the biodiesel it has created from the algae bioreactor to fuel a 2007 Ford E-350 passenger van that transports employees throughout the facility. In the future, the utility hopes to rely on the liquid fuel it generates—hopefully, in much larger quantities—for other practical purposes.

“Obviously, right now it’s kind of a novel idea what we’re doing here, that you can run vehicles on power plant emissions,” Hobbs says. “But it certainly does prove a point. One, you can make this fuel from algae and carbon-dioxide emissions. Two, you can actually drive a vehicle on it. That doesn’t leave anything for people’s imaginations.”

This, Hobbs hopes, is only the beginning. The utility hopes to continue studying its algae bioreactor as a research-and-development project through most of 2008. If all goes well, the utility would then move on to larger, perhaps commercial, production of the biofuels it creates from its algae.

The key, though, is to be able to create the fuel, and grow the algae, inexpensively enough so that it makes economic sense. That is the challenge that both GreenFuel and Arizona Public Service are now tackling.

The rewards for finding that right economic balance could be immense.

“We are trying to optimize this and find that commercial balance,” Hobbs says. “Algae are a valuable crop. It is a source of great chemicals and feedstock for fish farming. The trick is to grow it inexpensively enough to use it for fuel. That is the challenge of this whole thing. We are now trying to work on that whole issue; it’s a huge challenge. This would be wonderful if we could find the right combination to make fuel from. We would certainly have figured out a way to handle our country’s energy requirements, as long as there is a sun in the sky; it’s extremely renewable.”

So far, Arizona Public Service and GreenFuel have worked through two generations of design specifics for the Redhawk algae bioreactor, all in the hope of uncovering the most efficient system for producing enough biodiesel at a low enough cost.

The utility is now testing the third generation of bioreactor. Hobbs hopes this version represents at least one more step closer to a day when algae does become a key component of the nation’s energy usage.

“If we can get a good position on this to start with, if we can find a way to start this, we can have a tremendous impact on this country’s energy needs,” Hobbs said. “I’m certain that we can, with enough time and funding, hone this system. There is no doubt in my mind that we can hone this system. We have other technologies that have popped up in the last hundred years. Why couldn’t something like this work? This lends itself to that Manhattan project everyone talks about for energy. If we can get farther along on this, we can have an enormous impact on local economies. A whole new industry could spring up.” 

Writer Dan Rafter is based in Chesterton, IN.

DE - March/April 2008