The cheapest and quickest way to grow algae is also the riskiest. The shallow pools get great sun exposure and have little overhead costs, but they leave algae vulnerable to temperature changes, animals, and competing algae strains. HR BioPetroleum sidesteps these risks by growing algae strains first in sterile, transparent outdoor tubes before transferring them to open saltwater ponds for a day or two -- long enough to flourish and produce plenty of oil but not long enough to be contaminated. HRBP thinks its method is the only way to mass-produce algae oil at a reasonable cost, and Shell agrees. The oil company partnered with HRBP last December to begin construction on a pilot facility on the Kona coast of Hawaii. HRBP thinks it can scale up production to open a commercial facility capable of making more than one million gallons of oil a year as early as 2011.
There's a six-thousand-square-foot greenhouse filled with hanging plastic bags of green algae slush at Valcent's El Paso plant. The setup's purpose: expose the algae to as much sunlight as possible without the risk of contamination. Though much more expensive than growing algae in open ponds, Valcent believes its system is far more efficient because it can maximize oil output by precisely controlling the temperature and chemical composition of the algae solution. Valcent is perfecting its technology as it prepares to license it to outside biofuel companies, possibly as early as this spring. Its target is a system that is self-sustaining, with the algae increasing 50 percent in size every twenty-four hours.
Most scientists believe photosynthesis is the key to algae oil. Solazyme sees it as the problem. Algae can convert sunlight into chemical energy, but not nearly as efficiently as other materials -- industrial wastes, switchgrass, low-grade molasses -- can. So Solazyme designed a process that lets algae feed in the dark on input biomass rather than sunlight, cutting down the conversion process from weeks to days. The company's end-product diesels meet the same standards as nonalgal diesels, and it expects their price to be on par in two to three years. Until then, the company, which signed a development agreement with Chevron this year, will continue to clock miles in its algae-powered cars, standard vehicles purchased straight off the lot.
Most algae producers focus on diesel -- not only is it cheaper to produce, but it burns cleaner and more efficiently than gasoline. But sensing that America's conversion to diesel could come slowly or not at all, Sapphire Energy has used synthetic biology to make algae cells that automatically produce carbon chains nearly identical to those found in gasoline. Sapphire's gasoline emits as much carbon as petroleum, but because algae consumes atmospheric carbon, Sapphire claims its system is carbon neutral. In September, Bill Gates's investment company added an undisclosed amount to the more than $100 million Sapphire has raised, making it one of the best-funded algae start-ups. In three to five years, Sapphire expects to produce at least ten thousand barrels of gas a day.