When you hear “biofuel,” people tend to assume you’re talking about corn. That makes sense, given that corn is anticipated to provide 80 percent of this year’s ethanol production — much more, say, than algae — until we consider a few numbers. By all accounts, microalgae is less land-intensive than corn production, and although it can pull double duty, providing high-quality feed for fish farms, it doesn’t compete with food crops. Furthermore, even by the largely pro-corn Renewable Fuel Association’s water-consumption standards, corn ethanol is a thirsty fuel: Drinking 2.8 gallons of water for every gallon of fuel refined, corn is often outclassed in efficiency by algae-based fuels.
Algae biofuel frontrunner Algenol, for example, converts plentiful saltwater into biofuel with yields nearly 17 times higher than those of corn, while producing 1.4 gallons of fresh water per every gallon of fuel produced. But simple consumption comparisons between corn and aquatic fuels are often apples-to-oranges affairs at best. Much like the RFA’s figure, which ignores that growing an ethanol-gallon’s worth of corn costs 1,145 gallons of water, these facile metrics often miss something fundamental: Corn biofuel production consumes land, fertilizers, and water, whereas algae biofuel production can filter water, recycle runoff, and ameliorate emissions.
But if aquatic fuels are really such a comparatively comprehensive solution, why are we still so obsessed with corn biofuels? The old argument would be that aquatic fuels aren’t yet commercially ready, that costs and yields simply aren’t there yet. But with the Deparment of Energy doubling down on grants for competition-ready aquatic fuels, that story no longer holds up. Simply put, when faced with a burgeoning rank of algae-based platforms boasting well-tested estimate yields up to 2.8 times that of corn, and 32 to 70 percent fewer emissions than gas, corn looks increasingly weak.
Macroalgae, or kelp, is a marine biofuel source promising some benefits that outstrip even its single-celled cousin. Unlike terrestrial corn, kelp — cultivated or otherwise g rows into aquatic forests. In essence, the kelp farms that would fuel a marine biofuel industry, would also form the foundation of a functioning ecosystem — one that filters shoreline pollution and sequesters 6.7 tons of carbon per acre. As both kelp cultivation and the push for more sustainable seafood continue to grow, biofuel itself might soon become just another byproduct of an entire sustainable food production system.
Aquatic farms and ecosystems are simply more productive than terrestrial monocultures. So once again, perhaps it’s worth asking why we’re still primed to associate biofuel with its most old-fashioned manifestation.
Biofuel remains a stepping stool to better solutions — and aquatic biofuel remains more promising than corn.