The Biofuel Brew

March 1, 2009

Kristina Weyer knows just how important it is for Colorado residents, businesses, and industries to conserve water. The state is one of many in the western portion of the US facing significant water shortages. Scientists have predicted that Colorado may one day have to join a growing number of states that recycle and reuse their water to make sure they have enough to meet the water needs of their residents.

This need to conserve water is one of the many reasons why Weyer, an engineer with Boulder, CO-based alternative energy company Solix Biofuels, is so excited about a biofuel project that she and her fellow Solix engineers are working on in partnership with researchers at Colorado State University.

Solix and the university–at which Weyer studied as a graduate student before obtaining her degree and moving to work full-time at Solix–are working together to develop a water efficient technology to mass-produce algae that will, in turn, create oil that can be converted into biodiesel fuel. The project’s engineers hope to demonstrate that a plastic film-based photobioreactor designed by Solix can successfully, and cost-efficiently, create a low-cost feedstock for biodiesel production.

The goal is to commercialize this photobioreactor, thus giving the country a new tool to use in its efforts to create alternative energy sources that would help weed the US off its dependency on non-renewable fossil fuels.

The idea of harvesting algae to create biofuel is not new. Weyer says such efforts have existed since the 1970s. But, she says, the Solix project has the potential to make a big impact. Part of the reason is that the pilot program, if it is expanded one day to wide-scale use, will require far less valuable land than do other biofuel options, while, at the same time, wasting far less water than do other algae-to-biodiesel options.

“We have been very sensitive to water implications,” says Weyer. “Water conservation, using water efficiently, is a big issue in Colorado, and we are definitely working to make sure our project uses water as efficiently as possible.”

In the Solix project, which is now taking place at the Engine and Energy Conversion Lab at Colorado State University, engineers have designed a system that constantly recycles and reuses the water in which their algae stock grows. The water, after being processed and treated, simply circulates back into the system. It’s a
closed loop.

This feature helps resolve one of the big challenges engineers have faced with turning algae into biofuel: It wastes far less water than do most other algae-to-biodiesel projects.

In even more good news, Solix’s project is not the only algae-to-biofuels experiment now taking place at laboratories and universities. And, in the best news of all, it’s not the only one that uses water efficiently. For instance, an algae-to-biofuels project, taking place at the University of Minnesota, will, if all goes well, be fueled by treated wastewater.

Supporters say that this combination of a fast-growing feedstock and efficient use of water is providing the still-fledgling algae-to-biofuels movement a significant boost.

And as researchers continue to work toward solving the water-use issues still largely associated with growing and harvesting algae, the fast-growing plant may one day become the key feedstock in the young biofuels industry.

An Issue of Land
Proponents point to biofuels as a possible solution, or at least part of the solution, to the US’ efforts to rely less on fossil fuels. But opponents cite several problems with biofuel production: Creating fuel from such stock as corn or soybeans requires huge tracts of agricultural land. This can result in serious problems: If demand for biodiesel made from corn, or other food crops, increases, it could boost food prices even higher than they are now.

To make matters worse, the process of transforming corn and soybeans into fuel might actually raise the amount of greenhouse gases emitted into the atmosphere.

Algae, though, avoids many of these problems. That’s why Roger Ruan, a professor of bioproducts and biosystems engineering at the University of Minnesota and the director of its Center for Biorefining, is excited about an experiment he is now overseeing at the university. Ruan and his team of researchers are studying the potential of extracting oil from specific types of algae that are made up of as much as 40% oil to product biodiesel. The engineers are trying to discover what strains of algae grow best in wastewater. In the actual demonstration phase of the project, Ruan and his fellow researchers will grow algae at local wastewater treatment centers to test how fast, and well, the various types of algae grow.

Throughout the earlier stages of the program, Ruan and his researchers are screening wastewater through several varieties of algae species, to see which species grows best in it. The engineers are also developing their own photobioreactor to see what kind of system will minimize the amount of energy used, while still maximizing the growth of algae.

Ruan, like Weyer, hopes to one day see his pilot program result in an efficient and cost-effective commercial application.

“The potential for algae is extremely significant,” says Ruan. “The main thing is that algae grows really fast. You can’t even compare the algae oil and soybean oil production per acre. Algae easily beats soybeans. If you use algae, you can get a major, major increase in the amount of oil production. The most important issue, though, is that 90% of biodiesel cost comes from the cost of raw material. If we can produce oil stock, then we don’t worry about biodiesel production anymore.”

Ruan estimates that by using just one-sixth of the agricultural land available in Minnesota, farmers could grow all the algae needed to provide enough liquid fuel for the entire country.

“Algae could potentially be a major stock to produce biodiesel, to produce enough biofuels to replace liquid petroleum use,” he says.

The main hurdle to biodiesel, aside from the land issue, has been cost, Ruan says. He’s hoping to help change that with his algae-to-biofuel pilot program. “The processes are there,” he adds. “Right now, we have to figure out how to improve the efficiency of them.” How do you develop these systems for the efficient production of this algae? We need more efficient harvesting and oil production. It’s all about investing the time and money to improve the systems. That is what we are working on now.”

Ruan says he has no timetable for how long his current pilot program will last. He’ll be studying the oil-producing potential of algae for at least several years. It’s too important a project, he says, to not commit to it for the long-term.

Conserving Water
Algae, though, is not a problem-free stock for biofuel. For one thing, in open-air algae ponds, water evaporates. This is a waste of a precious resource.

With the Solix project now taking place at Colorado State University, evaporation is no longer as serious of an issue. Researchers here are growing their algae stock in a specially designed photobioreactor rather than open-air pools.

The problem is, most photo bioreactors are costly. But because Solix hopes to one day see the biofuel made from algae compete with the liquid fuel consumers pump into their cars, engineers with the Colorado State project have to keep production costs down. One way to do this is to create a photobioreactor that is not only effective, but also less expensive than traditional versions.

The solution? A highly engineered plastic film.

Solix’s photobioreactor is made up of 50-foot-long plastic-film tubes stacked atop each other. The film is filled with pockets of air to give the tubes structure. This allows the photobioreactor to maintain its shape, and provide an efficient growing system for algae. And it all costs far less than traditional photo bioreactors. What material, after all, is cheaper than plastic film?

Researchers will test their plastic-film photobioreactor with a commercial prototype at New Belgium Brewery, located a quarter-mile away from the Fort Collins laboratory. Project officials will install a half-acre prototype at the brewery.

Researchers with the project are now considering ways to further reduce water waste for this commercial prototype. They’ll continue to recycle the water in which the algae grows. But they are also exploring ways to reduce evaporation in the system’s thermal basin, a pool of water in which the photo bioreactor’s plastic panels are submersed.

One option is to apply a monomolecular film, much like the film used commercially in swimming pools and reservoirs, to reduce the evaporation in the thermal basin. Users would pour the monomolecular film into the thermal basin. Because it is lighter than water, it would float to the pool’s surface, where it would offer protection against evaporation.

Weyer, with Solix, says that she is looking forward to the commercial prototype at New Belgium Brewery. The potential for large-scale commercialization of algae-derived biofuel is impressive, she says. And every day, it seems, the team working on the Solix photobioreactor is coming up with new ways to tweak and improve the process of growing the algae.

“This is definitely a viable technology,” she says. “It’s amazing when you think of where it was when we started two years ago. The company, and the technology, has evolved so much. It’s particularly exciting to see how far this technology has come. When I first started, it was just a small group of students at Colorado State University working on this. Now we have a highly skilled team coming up with new and interesting ideas every day. We are starting to see how we are going to be able to take this to a commercial scale and make it work.”

The good news is that the climate seems right for algae-produced biodiesel, Weyer says. A growing number of researchers are working on projects designed to commercialize technology that would mass-produce oil taken from algae and transform it into biodiesel.

The idea of turning algae into biofuel has existed since the 1970s, Weyer says. But until now, the push to commercialize the technology–the key step toward making algae-to-biofuel a reality-hasn’t been there. “We needed the right economic and political climate,” says Weyer. “The higher gas prices are what everyone thinks of, but that’s really just one of the factors. There is so much focus on climate change recently in the media. That’s another factor pushing us toward biofuels. Everything has worked together to raise everyone’s awareness of using biodiesel as an alternative fuel source.”

The challenge with mass producing oil from algae, though, has not changed much since the 1970s: Can scientists find a way to grow algae cheaply enough on a large enough scale so that the cost of the oil produced from it would be competitive with the price of liquid petroleum?

That’s one of the factors with the Solix-Colorado State University pilot project that has Weyer, and the other engineers working on it, so excited. The plastic film used to create the photobioreactor is an inexpensive material. By lowering the costs of the production of the algae-derived biodiesel, the fuel can then be sold to end users at a lower price.

And this is the key to convincing the public–not to mention governmental agencies–that biodiesel is a viable option to liquid petroleum. Add the water conserving measures that the Solix project has incorporated, and algae-to-biodiesel sounds like a technology that can significantly reduce the nation’s dependence on liquid petroleum.

“The fact that algae grows in water is a significant advantage over other agriculture-based biofuels,” says Weyer. “You don’t have to take over great amounts of land. There are all sorts of conflicts involved with using farming land to produce fuel.”

A Commitment to Biofuels
Xcel Energy, an electric power and natural gas utility based in Minneapolis, MN, earlier this year gave a $150,000 grant to the University of Minnesota to help support the university’s work on renewable energy projects.

According to a company press release, Xcel officials are especially interested in the university’s algae-to-biofuels project, which is led by a partnership of the University of Minnesota and the St. Paul-based Metropolitan Council. The team working on this project is studying the possibility of using the more than 250 million gallons of wastewater that the Metropolitan Council treats each day to cultivate energy-producing algae.

The Xcel funding is helping to support to a pilot system to produce enough algae to help researchers develop and improve the harvest, extraction, and conservation processes associated with converting algae to biofuels. Researchers are developing a closed-loop system using wastewater and the heat produced by treatment plants to grow algae in cold climates, such as that of Minnesota.

The pilot program might also result in the reduction of greenhouse gas emissions. The wastewater solids incinerators at two of the Metropolitan Council’s water treatment plants release carbon dioxide into the atmosphere. If the pilot program goes well, both treatment plants could one day be capturing this carbon dioxide and use it to boost the growth of algae.

Jim Turner, environmental policy manager for Xcel Energy, says that the utility is interested in the algae project, because algae consume carbon dioxide. Xcel produces a significant amount of carbon dioxide. By transforming algae into an alternative fuel source, Xcel could put the carbon dioxide it generates to productive use, he notes.

“Projects like this, that combine environmental leadership with technology innovations, are the most attractive to us right now,” says Turner. “We are trying to combine environmental work with innovation. This project appears to have both.”

The University and Metropolitan Council are working together to seek additional funding to run a bench-scale study and a subsequent pilot-scale process demonstration over the next two years. During the study, Metropolitan Council Environmental Services plans to grow and harvest algae in a wastewater effluent flow of one-half liter per minute, which is equal to about 180 gallons a day.

Ruan says he and his fellow researchers have already found several specific strains of algae that work well in wastewater. He would not release the types of algae though, saying that the results of the pilot program are still considered proprietary information.

“We need to discover those strains of algae that grow well in wastewater-even very concentrated wastewater,” says Ruan. “And we’re not only looking for those strains that grow well, but also provide a high oil yield.”

Turner says he’s optimistic that the University of Minnesota project will produce some intriguing results.

“Right now the project is still at the conceptual stage,” he says. “But we’re very excited that this project will include an actual demonstration at a wastewater plant. It’s not only lab work that’s going to be done. We are very interested in the demonstration scale.”

About the Author

Dan Rafter

Dan Rafter is a technical writer and frequent contributor.