If you’re one of the millions of drivers fuming at the gas pump over the cost of fuel, pond scum may be the answer to your prayers. One group of scientists believes it could one day provide the world with an unlimited source of fuel.
Tasios Melis, professor of plant and microbial biology at the University of California at Berkeley, announced at the annual meeting of the American Association for the Advancement of Science that he and a team of U.S. Department of Energy (DOE) scientists have discovered a way to induce a lowly species of green algae, Chlamydomonas reinhardtii, to produce significant quantities of hydrogen gas. "Hydrogen is a good fuel because it burns clean, and it burns hot, and it doesn’t generate any pollution," says Melis. It’s so clean, in fact, that if a car were run on hydrogen fuel, the only byproduct would be clean (even drinkable) water.
Hydrogenis that safe?
But isn’t hydrogen what made the Hindenburg explode back in 1937? Not really, says Michael Seibert a scientist at DOE’s National Renewable Energy Lab (NREL). "The root cause of [the Hindenberg crash] was a diesel fireit wasn’t H2." Siebert, who works with Dr. Melis, also mentions that propane is much more dangerous than hydrogen. "Propane has caused a lot of accidents in this country, H2 relatively few."
For many years, scientists have known about H2’s ability to power engines without the toxic pollution and greenhouse effects caused by today’s hydrocarbon fuels. The problem is that they have been stymied by the shortage of supply. Currently, most H2 is obtained by breaking apart natural gasa process that is both expensive and a drain on the limited supply of natural gas. Enter the green algae.
Melis, Seibert and their teams started their research with C. reinhartii, an organism known for over 60 years to produce hydrogen gas under anaerobic (oxygenless) conditions. "It’s a green algae one can get in almost any pond in the country," says Seibert. "It’s a very common organism and it’s one we know relatively more about compared to other types of green algae." The problem was that the algae is also photosynthetic (oxygen producing), and as Melis notes, "The hydrogen production process and the oxygen production process in photosynthesis are mutually exclusive," meaning both cannot occur at once.
So the scientists discovered the means to "switch off" the oxygen production in C. reinhartii by deleting sulfur from the microscopic organisms’ environment. "Until now, no one knew how to reversibly switch off the oxygen production activity of photosynthesis, and essentially this is the discovery that we made," says Melis. "In the absence of sulfur, oxygen production by photosynthesis stops."
When will we be able to fill-er-up with hydrogen?
Scientists emphasize that H2 stations won’t spring up any time soon. "This isn’t gonna happen in the next six months or two years," says Seibert. "It’s a continuing process of research that will take continuing commitment to carry out and maybe hit pay dirt in 10 to 50 years."
One problem at the moment is volume. Each liter of algae culture normally produces 3 ml (that’s 0.1 ounce) of H2 gas per hour. But Melis and Seibert are working on increasing the hydrogen production tenfoldto 30 ml, or 1 ounce, per hour.
Also, Seibert reports that a mutant strain of the algae holds promise to make the H2 manufacturing process even cheaper and easier. "We have been able to demonstrate within the last six months a mutant organism that is able to produce H2 in the presence of small but significant amounts of O2, and so this represents a unique first step in our quest to produce an organism that will generate H2 in [the] presence of atmospheric O2." Also, he says, "We told the mutant if it didn’t produce H2 it was gonna die! Essentially we did this by adding a chemical that produces a toxic product that kills the organism when the organisam doesn’t produce H2."
Scientists working on the problem think that hydrogen powered cars, buses and trucks will provide clean, reliable and renewable transportation for humankind one day. And we may all end up thanking that slimy scum lining our pools, aquariums and stagnant ponds for producing the fuel to run them
"I often ask myself whether this is the beginning of the hydrogen era," says Melis. "We do not know. We will see."