Increasing the amount of oil that algae makes is one of the most promising ways to reduce costs. A number of other algae-biofuels companies are genetically engineering their algae to increase production, but Sapphire, instead, has developed a fast way to breed algae, select those with traits that can improve oil production, and make oil that resembles crude oil closely enough that it can be processed in ordinary refineries.
Sapphire has also bred algae that can flourish in open ponds. Other algae-biofuels companies use closed containers, which are more expensive but can help protect the algae from predators, fungal diseases, and other strains of algae that might take over a pond. Sapphire has bred disease-resistant algae that can grow under harsh conditions, such as high pH or salinity, that most other organisms can’t tolerate, reducing competition. It has also made them resistant to certain chemicals that inhibit the growth of other organisms.
Another major challenge is harvesting the algae. It takes about 1,000 grams of water to grow 1 gram of algae, and separating the two efficiently and extracting the oil can require a lot of energy. Borrowing techniques from water-treatment plants, Sapphire treats the algae with chemicals that cause them to clump together. The algae can be “squeegeed off the surface” says Tim Zenk, Sapphire Energy’s vice president of corporate affairs. The result is wet slurry that still contains a lot of water. Sapphire treats that with solvents at high pressures and temperatures to make three streams of products: algae oil, nutrients such as phosphates, and the leftover biomass. The oil goes to a refinery, and the nutrients and biomass are used to feed more algae.
The company is finding ways to reduce other costs. Rather than building concrete ponds, it is building cheaper ponds out of dirt and waterproof liners. It plans eventually to do away with the liners and make ponds that resemble rice paddies. Sapphire is also replacing energy-intensive paddle wheels used to circulate the algae with more efficient pumps, and is planning to design systems that use only the wind that sweeps across the New Mexico deserts for circulation.
The company is working with Munich-based Linde Group to develop a low-cost way to supply the algae with carbon dioxide, which is key to high productivity. Linde has developed systems for supplying greenhouses with carbon dioxide from a refinery.
Finally, Zenk says, the company may eventually turn to genetic engineering to further improve the performance of its algae.
When complete, the new 300-acre algae farm project is expected to produce about 100 barrels of algae crude per day, or 35,000 a year. Zenk says the process won’t be commercially viable without the economies of scale that will come with much, much bigger farms—1,000 to 5,000 acres.
Sapphire is a major beneficiary of the U.S. government. It received a $50 million grant connected to the 2009 Recovery Act and a $54 million loan guarantee from the U.S. Department of Agriculture. Its first customers may be the U.S. military, which is evaluating its fuels. Sapphire’s early funders included Bill Gates and a Rockefeller family fund. Monsanto is another major funder. It has an R&D agreement with Sapphire to identify genes in algae that might make corn, cotton, and soybeans more resistant to drought and other stress, and increase their yield.
Phil Pienkos, a research scientist at the National Renewable Energy Lab, says that Sapphire is doing a number of good things to reduce costs. Yet he says making algae fuels competitive will be a challenge. “It takes a certain amount of faith that there is going to be a business there,” he says.