Algae as a Biofuel

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  2. March 16, 2013 9:52 pm

Algae as a Biofuel

Pond Scum May Take Down Big Oil

Perhaps no other topic in biofuel science is as intriguing as the prospect of harvesting algae for a source of biofuel.

Algae need not compete with other crops for good land. They produce thousands of times more oil per acre than corn. During photosynthesis, algae produce oxygen and filter carbon dioxide from the atmosphere. Algae don’t require fresh water to thrive. They can feed on pollution and, in turn, become high-protein feed for livestock. Algae farms can create new jobs. Used as biomass, algae can produce numerous biofuels, including biogasoline, bioethanol, green jet fuel, biodiesel and vegetable oil.

Unfortunately, science has yet to solve several critical issues, including this: To produce ten gallons of renewable biofuel from algal biomass currently requires roughly ten gallons of nonrenewable fuel to complete the process.

To get plant-like algae to grow doesn’t take much. They need water, light, and carbon dioxide. Engineers, however, have yet to determine the optimal strains of algae for biofuel production. We must also learn how to control the growing conditions, prevent contamination and cost-effectively scale the harvest and extraction technologies if algae biofuels are to move from a concept fuel towards a viable commercial product.

Universities as well as the world’s leading petroleum companies and the National Renewable Energy Laboratory are working to resolve the prevailing issues of land use, yield optimization and the costs for capital equipment with which to process and extract oil. Chemical engineering research and development is expensive, and the financial returns on the investment likely remain decades distant.

Nevertheless, energy analysts are reasonably confident that the problems are solvable. Extracting oil from algae is not a complex process. Put enough algae in a press, squeeze it, and out squirts 75 percent of its oil. Mix hexane with the residue, and one can extract another 20 percent of the oil.

The extruded oil must be refined via transesterification, during which engineers add sodium hydroxide and alcohol to the oil, creating a biofuel with an additive, glycerol. Once engineers filter out the glycerol, the remainder is clean, renewable biodiesel fuel.


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