Grow Your Own Energy: Harvest Algae of Oil

All algae produce natural oils. We may just need to harness the right ones for an energy source

Before we run out of fossil oil, we will thoroughly tap the sea floor, find and frack wells wherever they may be, and excavate and extract the most recalcitrant of oil shales. In so doing, we will fuel our lifestyle for a few more decades at the cost of releasing vast amounts of carbon dioxide, adding to global warming, melting ice caps, raising sea levels, acidifying oceans—and setting course for a future for which there are few optimistic scenarios.
In the face of all this, scientists are racing to find alternatives. Biofuels are my passion, but they have had rather a bad press, from complaints about displacing food production to the inefficiency of soybeans and the carbon footprint of ethanol. Microalgae have a low profile but they deserve a much higher one, since the fossil oil we mine mostly comes from microalgae that lived in shallow seas millions of years ago—and they may be key to developing sustainable alternative fuels.
Algae are single-celled organisms that thrive globally in aqueous environments and convert CO2 into carbohydrates, protein, and natural oils. For some species, as much as 70 percent of their dry weight is made up of natural oils. Through transesterification (the process of adding three molecules of alcohol to one molecule of natural oil), the algae oils can be transformed into renewable fuels.

Microalgae hold great promise because some species are among the fastest growing plants alive and are therefore one of the best sources of biomass, while other species have been estimated to produce between 18,700 and 46,750 liters of oil per hectare per year, nearly a hundred times more than soybeans' 468 liters per hectare per year.
But there are big unsolved problems at which governments should be throwing funds and brainpower as if we were involved in a Manhattan project. For example, since few species of microalgae have been domesticated, we don't know how to grow them reproducibly or economically. At what scale will algae farming be efficient? To put this in perspective, U.S. planes use 80 billion liters of fuel per year. To supply this fuel from microalgae at the lower end of the estimated production rate would take 4.2 million hectares—twice the area of Wales.

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