How Energy From Algae Farms Can Lead to Our Next Biofuel

Drawing energy from algae farms is still costly, but can someday soon join a growing family of sustainable green biofuels.

| January 2014

Algae Farm

Our newest sustainable and green biofuel may be right around the corner as we improve ways to draw energy from algae farms.

Photo courtesy Jurvetson

The available energy sources on our planet and beyond are staggering in potential, but as Powering the Future (Basic Books, 2011) explains, the market will only move to such sources once the prices drop. From the possibilities of drawing energy from algae farms to tapping the almost limitless bounty of solar energy, renewable energy waits only for humanity to find effective means of production. Nobel Prize Winner Robert B. Laughlin describes a world in which we’ve burned every drop of petroleum and consumed every bit of coal, yet still have methods of sustaining our ways of life. In this excerpt from the chapter “Calling All Cows,” Laughlin writes of the potential for farming energy from algae farms, and the hurdles we need to overcome before it is a sustainable alternative for green biofuels.

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Drawing Energy From Algae Farms

The plants most likely to be exploited in the long term as an industrial carbon crop are saltwater microalgae. This prediction is somewhat of a stretch, because there is no saltwater agriculture industry at the moment from which you can make crop comparisons. However, microalgae grow, and thus fix carbon from the atmosphere, faster than any other plants in the world, so they’re very strong candidates. Their near-term production cost per unit mass is probably between five and ten times coal’s. This makes algae farms badly uncompetitive as an industrial carbon source while coal is plentiful but a potentially acceptable one when coal is exhausted. Other saltwater plants would have to beat this cost to win in the marketplace, and none of them can do so at the moment.

Microalgae also have an immense public relations advantage over other potential energy crops in that drawing energy from algae is quintessentially green. They’re not just natural things compatible with the environment; they’re the fundamental food source for the ocean’s entire ecosystem. These free-floating one-celled plants are visible at most ocean beaches as a green or greenish-blue tint of the light passing through the peaking surf. The powder blue color we find in open sea or in warm tropical waters indicates that the nutrients necessary for aggressive algae growth, chiefly nitrates and phosphates, are in short supply. But given a flow of nutrient-rich coastal runoff or a deep water upwelling, as we find on the Grand Banks of Newfoundland or Peru’s Humboldt Current, the water becomes turbid and green and abounds with life. Filter feeders such as shellfish, corals, and larval zooplankton eat the algae and multiply with abandon. Fish eat the filter feeders — and each other — eventually becoming abundant. Higher predators such as birds, seals, and killer whales eat the fish and likewise prosper. Commercial fishing operations thrive. The central role that algae may eventually play in the human economy when the coal runs out is thus extremely appealing, in that it echos the role they already play in the sea.

Farming algae is difficult, however... The fundamental reason why is that they achieve their great fecundity by avoiding responsibility, not by being gifted. A conventional food plant like corn has stems to erect, roots to put down, leaves to unfurl, seeds to generate, and so forth, not to mention longer-term things such as waiting for spring. But algae do none of these things. They lead a short, brutal life of freedom rather than a long one of endless toil, and they just don’t care about tomorrow. As a result, we have to do their chores for them if we want to raise them, and that costs money. The extra costs wind up being so great that no one can figure out how to farm algae profitably. That isn’t so surprising, for pure algal biomass is a green substitute for coal, a resource that is extremely cheap at the moment and correspondingly hard to beat. But the problem is worse than that, for algae become less productive than conventional agricultural plants, not more productive, once we discount the extra costs of raising them. Algae farming will probably not become a significant industry until both coal supplies and land resources for agriculture have run out.

Algae’s monumental cost problems make it almost impossible to take present-day algae biofuel companies seriously. We want to believe, but we find ourselves thinking instead about all those nutritious government subsidies. The most unforgettable of these subsidies is the high-priority U.S. congressional mandate that the Air Force secure a supply of green jet fuel at any price. Exactly how much the Air Force is paying isn’t public knowledge, but rumors are that it’s about ten times the cost of jet fuel made from petroleum.  Not surprisingly, saltwater agriculture is a rather low priority with startups jockeying to supply this fuel, as is agriculture generally. For example, one of them is reported to be growing algae in plastic bags (made from petroleum) stacked in warehouses. Another isn’t engaging photosynthesis at all but is instead grazing its algae in the dark on cheap sugar, presumably obtained from conventional crops such as beets or cane. Another eschews growing algae completely and plans instead to harvest the fish that eat them, no doubt with the objective of grinding the fish up and processing the happy brew into gasoline and diesel fuel.

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