You may have heard that we’re entering an algae farming boom. Biofuel produced by algae reared on greenhouse gases is supposed to replace fossil fuels with a climate-friendly brew. But if you try to refuel your car, tractor, or Cessna using this vaunted energy source, you’ll quickly realize that hype alone cannot stroke an engine. Algae biofuel isn’t for sale. At least, not unless you can get your hands on experimental samples being produced in laboratories. After more than 35 years of federally funded research, the cost of producing algae biofuel is a lichen-covered cliff that separates it from the ocean of cheap fossil fuels.
Despite algae biofuel’s economic shortcomings, though, there’s a feast of good news for supporters of slime-driven climate action. Algae are being cultivated commercially, and in growing volumes. They are being grown in waters enriched with carbon dioxide, climate-changing waste gases that can be pumped into algae ponds from mines, power plants, and factories.
Oil from the commercial harvests isn’t being sold as fuel. It’s ending up inside something more intimate than a rush-hour crowd in a biodiesel bus. It’s sold as food. The oils, proteins, and carbohydrates from farmed green slime are fueling the cells inside our bodies.
Algae is an imprecise word. The spongy plantlike species that we dump into the taxonomic algae bucket don’t all come from a common ancestor. Algae is one of those “you know it when you see it at the end of your fishing line”-type things. Some single-celled strains are microscopic; giant kelps can stretch 200 feet. Humans have eaten some seaweed varieties of algae for countless generations; other kinds of algae poison swimmers at beaches seeped in sewage. Today’s algae include the descendents of some of the first organisms to suck up carbon dioxide, use solar energy to combine the carbon into sugars and proteins, and create our animal-friendly atmosphere by pumping waste oxygen out after photosynthesis. Some algae light up oceans at night in glowing blues or paint them blood-red during the day. Some are carnivorous, preying on passing zooplankton—the microscopic equivalents of hypothetical savanna grasses that grab and devour passing gazelle.
Many algae species occupy the bottoms of food chains. When fish graze on algae, or on zooplankton that fed on algae, they absorb energy that the algae plucked from sunrays, and they lap up the algae’s nourishing fatty acids. These are the same acids that we hanker for when we buy fish oil tablets in hopes of lubricating our weary joints.
“You’ve got a bunch of algae out here, right?” President Obama said during a 2012 energy speech at the University of Miami. The Floridians laughed. They’re accustomed to pollution-fueled algae outbreaks that ruin their beaches and kill their pets. Florida’s lawmakers are considering spending $380 million next year to clean up 38 natural springs—waterholes popular with divers but infested with mats of algae following decades of pollution runoff. More than 100 manatees died in the Indian River Lagoon last summer. Scientists say they were poisoned after eating a type of algae that flourishes in pollution.
Algae can be a formidable environmental foe for the same reason that farming them seems so attractive—because they can prosper with so little. Warmth, sunlight, and nutrient-tainted waters are all they need, and these ingredients are in rich supply in many American states. Gulf of Mexico algae outbreaks fueled by Midwestern agricultural runoff trigger an annual oxygen-depleted dead zone that reached 5,840 square miles last summer. “If we can figure out how to make energy out of that,” Obama continued, “we’ll be doing all right.”
The thing is, we’ve already figured out how to make energy out of that. It’s just that nobody is doing it—not on a commercial scale, anyway. Farming and refining algae biofuel remain economically unviable. By National Algae Association estimates, a company would need to farm 250 acres of algae before it could start turning a profit on biofuel. That could change by 2020, if industry insiders who responded to an Algae Biomass Organization poll turn out to be correct, with growing costs expected to come down.