Pond-scum power: going really green

SINCE the days of Richard Nixon, the United States has sought a replacement for oil, for reasons economic, political, and environmental.

Our reliance on oil makes our economy vulnerable to oil-price spikes. Each oil-priceA shock since the 1970s has been followed by an economic recession, and as our oil imports have risen, that impact has become more severe. Some economists credit the most recent oil-price spike with contributing to, or even kicking off, the global recession.


Also, keeping military equipment moving uses a lot of oil. The U.S. military uses 130 million barrels of oil each year, which is about how much the entire country of Sweden uses. The idea of being dependent on oil supplies from hostile regimes is troubling, as is the idea of facing guns and bombs that were purchased with dollars you provided.

Adding to the pressure to find a replacement for oil is the drumbeat of alarm over greenhouse-gas emissions, especially as China and India continue their economic development, adding millions of gasoline-powered vehicles to the world’s roadways.

Unfortunately, an economically feasible replacement for oil is hard to find, because oil is a marvelous, energy-dense fuel, inexpensive compared with alternatives. Ethanol from corn, a favored contender as an alternative to gasoline, has lost its luster as it shows itself to be both economically and environmentally disastrous. (The government continues to subsidize it, of course.) Converting coal to liquid fuel is a proven technology, but it too fails tests both economic and environmental.

But a new contender has entered the ring. That contender is (drum roll)–pond scum. More precisely, algae, which can be turned into a renewable, environmentally friendly replacement for gasoline, diesel, aviation gas, and more. Algae fuels hold so much promise, in fact, that venture capital is pouring into their development even in the face of a massive recession–suggesting that, unlike other “green” fuels, it won’t need government subsidies to thrive. More than 150 companies around the world are putting money into algae-fuel research. And you know things are serious when Big Oil buys in: Shell, Chevron, Conoco-Phillips, and ExxonMobil have jumped into the pond with big money, hoping to find another source of liquid fuel to complement oil in meeting expected world demand. ExxonMobil is in the game to the tune of $600 million, serious money even for them.

Here’s how it works. Algae use sunlight to convert carbon dioxide (the dominant man-made greenhouse gas) into sugar molecules, which they then convert into the myriad chemicals they need to live. They have high population-growth rates, and, most important, they’re oily: About half their mass is fat, which can be chemically converted into diesel fuel, gasoline, aviation fuel, etc.


Several things make algae especially interesting from a fuel perspective.


The National Renewable Energy Laboratory estimates that algae can produce 10,000 times more oil per acre than other biofuel crops, such as soybeans.


Algae don’t compete with food crops for land. Algae don’t need arable land, just flat land, where they’re grown in long, oval, racetrack-like ponds. Algae can also be grown in enclosed growth systems, which can be just about anywhere there is a combination of warmth, sunlight, and surplus carbon dioxide.


Unlike ethanol, algae don’t need to consume fresh water. They can grow on salty water, or even waste water, which they clean up as they grow. By contrast, according to some estimates it takes 140 gallons of fresh water to produce a gallon of corn ethanol.


The stuff left over after you squeeze all the oil out of algae is a mixture of protein and sugars that can be used in many different products, including animal feed, bio-plastics, and pharmaceuticals, or you can just chuck it into a furnace and generate electricity from steam. We already use algae for all kinds of things, such as food, coloring agents, pharmaceutical production, and treating sewage.


Yhere’s the greenhouse-gas connection. Algae fed on the carbon dioxide in regular air are carbon-neutral. They pull carbon dioxide out of the air when they grow, and it’s released back into the air when they’re used as fuel.

Of course, there are plenty of challenges to be overcome. The best strains for given growing conditions have to be identified and optimized. Algae grown in open ponds are susceptible to weather, predation, and disease. If fresh water is used, evaporation becomes a significant problem, increasing water use.

Will algae fuels let us have our Hummers and drive them too? Nobody knows yet, but with the private money pouring in from around the world, there’s certainly nourishment for the scum to grow on.

Green, Kenneth

==> See more about algae: Since the algae, efforts to save water run deep – Rural Finance – Business Surveys Series