Rehabilitating Pond Scum

A term typically reserved for society’s worst miscreants may soon undergo a radical transformation.

Pond scum, understood in its original usage as a synonym for free-floating algae, could fundamentally alter the U.S. energy landscape — for the better, many energy experts believe.

In fact, a fervent race already is under way at universities throughout the country to turn this common substance into a commercially viable energy product.

As the New York Times reported Dec. 2, some algae are made up of as much as 50 percent oil — oil that can be converted into biodiesel or jet fuel. But the biggest hurdle — one that has stymied many otherwise promising renewable energy sources — is cost of production. By one Defense Department estimate, converting algae into a biofuel source could run higher than $20 a gallon.

The goal is to find some way to whittle this cost down to around $2 a gallon. But the question remains how.

Researchers also are busy figuring out how to extract the oil from algae and identifying the strains best suited to mass production — efforts that are being helped along by a diverse array of supporters, including government, particularly the Department of Defense, venture capitalists, utilities and even big oil.

But it likely will be several years before demonstration plants are built and likely many years more before algae is converted on any sort of mass scale.

But if this potential fuel source ultimately becomes cost effective, the results could be far-reaching, according to Mark Hall, the Alabama Cooperative Extension System’s renewable energy specialist.

Hall has tended to describe other forms of renewable energy as niche technologies — technologies that will help fill some of the gaps in renewable energy needs. Algae, on the other hand, has potential to become much more.
“This is bigger than a niche – it could be a big player,” Hall said in an interview earlier this year.

Also, compared with other biofuel sources, algae likely will require considerably smaller amounts of land for production, leaving much smaller environmental footprints.

According to one estimate, an acre of corn can produce some 20 gallons of oil a year, while an acre of algae could produce a possible 15,000 gallons of oil.

One thing is virtually certain: If pond scum ever is developed into a viable renewable energy resource, Alabama, because of its moderate climate and plentiful water supply, could profit in a big way. In fact, venture capitalists already have begun considering how algae could be raised in ponds with catfish, which could provide the algae with an ideal source of carbon dioxide.

Also, from a bioenergy standpoint, some of the more appealing strains of algae are found in saltwater. Some of these conceivably could be grown in saltwater aquifers in western Alabama, said Dr. Paul Mask, Alabama Extension’s assistant director for agricultural programs, in an interview earlier this year.

But, again, challenges abound. For starters, Alabama isn’t warm enough to raise algae year-round, at least outside. Moreover, algae grow near the surface of water, and the deep ponds associated with catfish aren’t the best suited to grow algae.

That may present big obstacles, at least under current technological constraints, Mask says.

There are the added challenges of harvesting and drying algae.
Even so, Mask believes Alabama has a key asset working in its favor: a world-class fisheries program manned by experts who know how to manage water and manipulate it to provide optimal conditions for algae.

Posted by Jim Langcuster at December 6, 2007 02:07 PM