Bioenergy

The Algae Attraction

Some recent breakthroughs in technologies to achieve carbon-neutral coal plants now exist while others are years away. One such concept is to use waste carbon emissions from power plants to grow algae, which is subsequently converted to energy and because those releases would be re-cycled, carbon dioxide emissions would be cut in half.

Views range from enthusiastic to reserved. It’s a sensible alternative but one that will not end the debate over which fuel sources will best meet the global community’s future energy needs. In fact, if the theory can be scaled up and used at power plants, the subsequent reduced emissions might even encourage the use of coal.

Consider NRG Energy, which is field testing the technology at one of its coal-fired plants in Louisiana: It is using naturally-occurring algae to capture and reduce flue gas carbon dioxide emissions. The energy-rich algae are harvested daily and can be converted into a broad range of bio-fuels or high-value animal feed supplements.

Power generators can choose to dry and store the carbon-rich algae biomass for use as renewable fuel for the power plant or change it into valuable transportation fuels such as biodiesel or ethanol. Industry experts say that the rule of thumb is that it takes two million tons of algae to be able to capture one million tons of carbon dioxide. The process requires no re-engineering of the power plant, the utility says.

“Coal is — and will remain — the premier domestic fuel source for power generation purposes in the United States for the foreseeable future,” says David Crane, NRG’s chief executive. “This means it is incumbent on us not only to build new coal plants using technology which limits or eliminates greenhouse gas emissions but also to find the best way to retrofit the country’s existing fleet of coal plants for post-combustion carbon capture.” The company is continuing to monitor the algae carbon-capture technology.

Roughly a third of all carbon dioxide releases come from power generation. Coal is the biggest culprit with natural gas-fired power a distant second.

While using carbon dioxide to cultivate algae is not new, taking it from power plants and turning it biodiesel and ethanol is ground-breaking. It was first done by Arizona Public Service and GreenFuel Technologies in 2006, marking the first time ever that algae grown on-site by direct connection to a commercial power plant had been successfully converted to transportation-grade bio-fuels.

Now that the initial tests have shown promise, the next step is to prove it can all be done on a commercial scale and that it is financially viable. Moving to a coal plant is the next progression in the evolution of this technology — something in which government researchers are assisting. Interestingly, participants acknowledge that conversion strategies have been more successful than carbon-trapping ones. “With the help of forward thinking and environmentally responsible companies, we can use algae to recycle power plant carbon dioxide emissions safely and economically into a continuous supply of clean, renewable fuels,” says GreenFuel CEO Cary Bullock.

Taking Bets

Meanwhile, a San Diego-based company called Sapphire Energy says that it too can take the carbon dioxide that is released from power plants and transform it into algae. That, in turn, can then be converted into a greener form of gasoline and diesel. The end result — high-value hydrocarbons chemically identical to those in gasoline — will be entirely compatible with the current energy infrastructure from cars to refineries and pipelines.

Everything from the byproducts released at the refineries to those shed from tailpipes will be cleaner, it says. The company adds that it will soon establish a pilot project, all with an eye on making it commercially feasible within five years.

In the end, Sapphire says that development of the fuel source will be cost competitive with other unconventional fuels such as those that produced from Canadian tar sands. Those energy forms, incidentally, have not bypassed the scrutiny of environmentalists, who acknowledge the potential but who fear that that the total production cycle is ecologically harmful.

“Sapphire Energy was founded on the belief that the only way to cure our dependence on foreign oil and end our flirtation with ethanol and biodiesel is through radical new thinking and a commitment to new technologies,” says chief executive Jason Pyle.

Algae, which is homegrown that can be created anywhere sunlight exists, has the potential to ingratiate itself into the energy mix. The ultimate fuel form could either be used in conjunction with fossil fuels or possibly to displace them.

That’s vital, considering that coal provides more than half of the fuel needed to make electricity in this country. Meanwhile, the United States keeps importing ever-increasing amounts of foreign oil. Last year, the number totaled $200 billion. The increased demand is the major reason behind record-high prices at the pump.

“It’s hard not to get excited about algae’s potential,” says Paul Dickerson, chief operating officer of the Department of Energy’s Office of Energy Efficiency and Renewable Energy. “Its basic requirements are few: carbon dioxide, sun and water. Algae can flourish in non-arable land or in dirty water, and when it does flourish, its potential oil yield per acre is unmatched by any other terrestrial feedstock.”

The verdict is still out. It’s not just a question of whether algae-based fuel can work on a large scale but also whether the production cycle turns out to be environmentally benign. Imbedded within the discussion, however, is an inspiring message: Researchers are convinced that the idea works, leading some risk takers to make substantial bets.

Ken Silverstein is an award-winning journalist who is the editor-in-chief of Energy Central’s publication, EnergyBiz Insider. With a background in economics and public policy, he has spent several years writing about the issues that touch the energy and financial sectors, and his work has been published in more than 100 periodicals.

Republished with permission from CyberTech, Inc. EnergyBiz Insider is published three days a week by Energy Central. For more information about Energy Central, or to subscribe to EnergyBiz Insider, other e-newsletters and EnergyBiz magazine, please go to http://www.energycentral.com/.