Algae, Biofuel and CO2 Capture
Algae, Biofuel and CO2 Capture
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Algae, Biofuel and CO2 Capture
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Algae is proving to be useful as a potential fuel source in a world where fossil fuels are on the way out. By converting algae to a biofuel, greenhouse gas regulations could be met by many organizations.

Algae wouldn’t make most lists of high-value crops. But certain algae present an opportunity for sequestering carbon dioxide (CO2) emissions while producing biofuel. In light of possible greenhouse gas (GHG) legislation, that could be pure gold.

“The idea of producing fuel from algae isn’t new,” says Robert Healy, manager of renewable energy development for Burns & McDonnell. “The U.S. government began financing research into oil-producing algae in the 1970s. But in the last two years there has been rapid development of systems designed to use algae to produce biofuels.”

Why Algae?

The renewed interest in algae is partially a response to criticism of the use of food crops for alternative fuels. Such use, critics say, raises commodity prices and exacerbates water shortages. Unlike the corn used to make ethanol, or canola that becomes biodiesel, algae growth systems don’t require land suitable for food crops. But to be technically and economically feasible, algae-to-biofuel systems, called bioreactors, have had to overcome several challenges.

Growing enough algae to produce substantial amounts of fuel requires large amounts of surface area. While some proposed systems use open ponds, newer algae bioreactors use plastic tubes or thin sheets of plastic in vertical frames. These closed systems take up less space, use less water and allow carefully metered application of nutrients, but they are more expensive than open ponds.

Putting CO2 Emissions to Work

Another challenge lies in separating the oil from the algae and growth medium — an energy-intensive process. Depending on the availability and price of alternatives such as conventional diesel, it has been difficult to produce a competitively priced product, and one that doesn’t lose its environmental advantage due to the amount of energy required to make it.

Healy is working with a large power producer in the southeastern United States to develop a pilot project that will test an integrated, algae-to-biodiesel system using CO2 emissions from a power plant to support algae growth. CO2-rich gas from smokestack emissions will be added to the tubular network of an algae bioreactor, where it will speed production of special high-lipid algae — which absorb the CO2 in the process. An on-site biorefinery will extract the algae oil and convert it to biodiesel, glycerin and other products from the dewatered algae.

Meeting a Need

Fossil-fueled power plants are one of the largest single, stationary sources of CO2 emissions. Despite efforts to add wind, solar and additional nuclear power plants to the mix, fossil-fueled power plants still produce the bulk of electrical power required to meet U.S. utility customers’ demand.

The Environmental Protection Agency’s recently published Mandatory Reporting of Greenhouse Gases Rule requires facilities emitting 25,000 metric tons or more of GHG to report CO2 emissions. Additional regulation imposing a penalty for GHG emissions — or providing incentives to reduce them — is widely expected.

“When there’s a need, new technology comes in to fill that need,” Healy says. “With the threat of carbon regulation, utilities are looking at all options to reduce their carbon output.”

A side business in algae may be one of those options — and a possible energy solution for the future.

For more information, contact Robert Healy, 816-823-7102.

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