Colorado State University and Solix Biofuels, Inc., a Boulder-based start-up company, are working in partnership to develop technology to mass-produce algae that create oil that can be converted into biodiesel fuel.
The Solix photo-bioreactor system, beta model shown here, which grows algae in temperature controlled closed plastic bags is the novel part of their process and the focus of development at Colorado State University.
Solix plans to commercialize the technology over the course of the next two years and expects to be able to compete commercially with the wholesale price of crude petroleum.
"Algae are the fastest growing organisms on the planet, and can produce 100 times more oil per acre than conventional soil-tilled crops that are now being grown for biofuel use," said Solix founder Jim Sears.
Solix technology captures the sun's energy through photosynthesis to grow algae, capture CO2 and produce valuable, energy dense "bio-crude". This patent-pending production system offers a scalable system that cheaply and effectively grows algae and optimizes oil production. By reducing the costs of energy input and initial capital outlay, the promise of algae based biofuels that are price-competitive with petroleum fuels is, for the first time, reachable.
Solix officials estimate that widespread construction of its photo-bioreactor system could meet the demand for the U.S. consumption of diesel fuel - about 4 million barrels a day - by growing algae on less than 0.5 percent of the U.S. land area, which is otherwise unused land adjacent to power plants and ethanol plants. The plants produce excess carbon dioxide, which is necessary to turn algae into oil. In addition to producing biodiesel, the process would prevent a large portion of the greenhouse gases produced by coal-burning power plants from being expelled directly into the atmosphere.
Colorado State and Solix officials are collaborating with New Belgium Brewing Co. to use excess carbon dioxide from the brewery's plant to test the algae-based biodiesel process.
Two problems were encountered in early attempts to grow algae for the production of oil: 1) the open ponds in which the high-lipid-concentration species of algae were grown were quickly colonized by local indigenous algae that had much lower levels of lipids. 2) the costs of regulating temperature in the open ponds was inordinately expensive.
The bioreactor designed by Jim Sears, founder of Solix Biofuels Inc., grows algae within closed plastic bags, which reduces the possibility of infestation drastically. And a novel low-energy temperature control system keeps the algae within a temperature range that optimizes growth.
How Solix turns algae into oil: Algae are grown in a very large bioreactor that primarily consists of two enormous transparent flattened tubes made of specialty plastics. Water weighted rollers squeeze the algae-bearing fluid through the tubes as they slowly move down tracks built into concrete supports on the side of the tubes. The peristaltic motion of the rollers creates a current inside the reactor, which force the algae to be in constant motion. This motion allows more than just the top layer of algae to receive sunlight. That in turn allows the fluid depth of the reactor to be 12 inches deep and not restrict photosynthesis to the surface layer of the fluid-a traditional obstacle to making cost-efficient photosynthetic bioreactors.
Within the bag is a thermal layer that can be raised or lowered by the rollers to regulate the internal temperature of the bioreactor. The shape of the straps holding the foam are designed to maximize the fluid rotation within the reactor, presenting all the algae sequentially to the sun absorption zone in the top layers of the reactor. This is where photosynthesis combines hydrogen from water with the carbon from the injected CO2 to form energy crops of vegetable oils and carbohydrates.
Algae cells are harvested from the fluid with a centrifuge. Once harvested, the oil will be extracted and the resulting oil can then be refined into biodiesel fuels through the same transesterification process currently used to refine other vegetative oil sources into biodiesel. The algae oil can also be refined into other liquid fuels, including ethanol and jet fuel.
Once land for the bioreactor system is acquired and basic infrastructure is completed, the only inputs into the system are sunlight, carbon dioxide, trace nutrients and a minor amount of energy needed to push the rollers. No external heating or cooling source will be required. The energy balance of the system is expected to greatly exceed that of conventional soy and canola-based biodiesel operations.
Because of the low capital costs of the bioreactor design, and the fact that the CO2 can be sourced from biomass-fed electricity plants rather than only coal or natural gas, it presents opportunities for developing countries also.
"This is an ideal solution for producing liquid transportation fuels while absorbing greenhouse gas emissions through growing biomass in countries that don't have access to fossil oil or coal," Sears said.
This system is quite a departure from other algae growing systems and addresses previously identified problems. To solve these problems are developing a system that is more mechanically complex than other systems, but still quite simple. This system should take less land area than the static tubes that are being developed by others and harvesting the algae should be easier. I wish them luck.
Additional resource: Background on Solix Biofuels Inc. System, Colorado State/Solix Biofuels, Press release, Dec 7, 2006