Advertisement

Image: CellanaAs early as the 1950s, researchers were looking at algae for methane gas production. The algae was grown on rooftops of Massachusetts Institute Technology (MIT). Drawings and illustrations of open pond raceways on the roof of Harvard Univ. were also recovered from the 1950s. The reason for this research was algae naturally make oil, and this intrigued researchers as a feedstock for biodiesel.

In the 1970s, algae for use as an alternative fuel had another push, this time related to gas-related fuels. And this push came when the U.S. Dept. of Energy (DOE)’s National Renewable Energy Laboratory (NREL) started a program called the Aquatic Species Program. The program was originally meant to evaluate photosynthetic organisms that grew in or near water—including algae, seaweed, swamp-type plants and more. The program was looking for ways to supplement the amount of terrestrial biomass that could be grown, looking at different aquatic species. And very quickly into this process, NREL settled on algae, more specifically microalgae, due to their ability to produce lipids, which were known as a potential source of biofuels. The project lasted from 1978 to 1996, at which point the price of oil had gone down to about $10 to $20/barrel. And the price was thought to stay at that price for a long time.

Since the interest dried up due to the decreasing price of gasoline/oil, the DOE could no longer hold funding across the board on biofuels, so they terminated the algae part of the program to continue focusing on cellulosic biofuels. From 1996 to 2006, little work was done on algal biofuels. Then, starting in 2007, interest was, yet again, sparked when the price of oil rose to $40 to $50/barrel; and companies started to form the Algae Biomass Organization in 2008. From there, algal research started up again with a vengeance.

Despite the ups and downs, this alternative fuel source has seen its renaissance today, with similar funding (over $18 million spread across national labs, universities and industrial companies from the DOE and more from private sources) and more interest from companies in its potential.

The trouble of commercialization stunts benefits
The onset of the rise in algal biofuels research in 2006 and 2007 was the publication of the first billion ton study, which was a joint effort between the USDA and the DOE. The study posed the question of how much terrestrial biomass or lignocellulosic biomass could be sustainably produced in the U.S? And the answer, according to the study, was about a billion tons per year.

“Looking at the different conversion properties and processes to turn cellulosic biomass into fuel, you can basically assume a billion tons a year could be used to produce about 60 billion gallons of gasoline equivalent a year—whether that is ethanol or some other fuel molecule,” says Philip Pienkos, Group Manager of the Bioprocess R&D Group at NREL in an interview with R&D Magazine.

As a nation, we burn about 140 billion gallons of gasoline a year. We also burn 40 billion gallons of diesel, and 20 billion gallons of jet fuel. “Cellulosic biomass can only cover a small fraction of this,” says Pienkos. “Our calculations show algae could easily match cellulosic biofuels in terms of overall production. It could actually exceed the cellulosic biofuels we produce because of the lipids, sugars and other components found in algae. There is enough free space in the U.S. that isn’t being used that can cultivate algae; so, easily, 60 billion gallons of biofuels could be produced in the U.S.”

However, the DOE has set a more conservative target, and is looking to establish 5 billion gallons of algal biofuels a year, with a notion it could be an order-of-magnitude higher.

Yet, the commercialization of algal biofuels has proved much harder than expected. And some view algal biofuels as more hype than a reality.

“The joke is algal fuels are 10 years off, and they always will be,” says Pienkos.

However, the main reason why algal biofuels haven’t exploded yet is the reason why most are getting their funding: Algal biofuels aren’t quite economically viable to compete with gasoline. “They are getting there,” says Rhona Stuart, Postdoctoral Researcher at Lawrence Livermore National Laboratory in an interview with R&D Magazine. “And there’s research being conducted in all different pipelines, not just in the growth of algae, but also the production and conversion of algal biofuels to get it to the point where it competes with gasoline at a cost per gallon.”

To help alleviate this issue, there has been much effort from the national labs and DOE-funded projects that look at techno-economic analysis and lifecycle analyses of algal biofuels. And these projects have identified two key barriers to getting these biofuels within the cost per gallon range of gasoline: low yields of algae biofuels and high costs of producing algal biomass. “The goal for the funding provided by the DOE is getting the gasoline gallon dollar equivalent of biofuel product down to less than $5/gallon,” says Stuart. “And right now, by some estimates, it’s at around $8/gallon.”

“If you look at the petroleum industry, worldwide it’s a trillion dollars a year industry,” says Pienkos. “And that’s the magnitude of the opportunity for biofuels and bio-based chemicals. We are talking about an algae industry that could be on the same order of magnitude, or thereabouts, as the petroleum industry. And it’s going to take a lot of money.” The industry is starting small, and it will take success at the higher-value, smaller-market products to establish commercial revenue streams. In response, high-value products will be the main focus for near-term commercial success. And it is hoped that those revenue streams will lead to further R&D progress, eventually ushering large-scale algal biofuel production (and some companies are well on their way, such as Sapphire, Cellana and Algenol).

Yet, despite the cost issue, there are many benefits to using algae instead of gasoline. How algae compares to gasoline is highly determined on the strain of algae used and chemically what oil that strain makes. Currently, some companies are engineering algae to produce oil very similar to a gasoline equivalent biodiesel that could be dropped into a car. Other downstream processes harvest the biomass, not just the oil, and convert it into ethanol.

“In general why algae is a good alternative is because it’s carbon neutral,” says Stuart. “Algae is grown on non-potable water, maybe even wastewater, so you’re not using water and you’re not using arable land, because you are growing this algae in ponds. This means the cultivating of algae isn’t interfering with our food source. The algal biofuels, once produced, will take up carbon dioxide and burn that carbon dioxide immediately in a car, showing a carbon neutral process.” Essentially, the algae is taking up the same amount of carbon that’s released. In addition, algae can produce mass quantities of lipids and fats, making them easily convertible into liquid fuels, such as biodiesel or jet fuel.

The barrier of pond crashes
A large barrier to the commercialization of algal biofuels is pond crashes, where algae will begin to grow and then suddenly die off. The reason ponds crash is because they are open to the atmosphere and many deleterious species come into the pond and either eat or infect the algae. These pond crashes are unpredictable and must be understood to minimize their devastating impacts—basically losing whole algae harvests and starting over again.

Image: AlgenolSince theses crashes are unpredictable, they also are an economic barrier to making algal biofuels viable to replace gasoline, and the process to developing algal biofuel ponds and cultivating the algae is a time-consuming process, taking months. “The reason the process takes months is researchers must clean these ponds from any infected deleterious species that may have gotten in and caused the crash,” says Stuart. “That is a huge liability. So, if we can prevent even 10% of those crashes, we can really improve the annual yield.” Annual productivity is a key metric for algal biofuel production that, if optimized, could significantly decrease and stabilize biofuel price per gallon. Larger yields give algal biofuels the competitive boost they need to compete with gasoline.

To study these pond crashes, the DOE has awarded Lawrence Livermore National Laboratory $1 million over the next three years. “This is new area for us at Livermore Lab, and we are only just beginning to understand the pond microbiome isn’t only an indicator of health, but also a tool for crop protection. The project will start officially on Oct. 1, 2015,” says Stuart. “But we are leveraging some other work that got funded last year in October that’s much more basic research—it’s not as applied as our project—to look at algae and the bacteria that are attached to the algae.”

The research will focus on a special region called the phycosphere, a boundary layer around an algal cell, where there are many important interactions between algae and the beneficial bacteria that can attach to the algae and help them grow. “We are trying, at a very fundamental level, to understand how these beneficial bacteria attach and interact with the algae in the phycosphere, which surrounds an algal cell,” says Stuart.

While still in the early stages, Livermore Lab is hoping to identify and employ what Stuart calls “probiotic bacteria,” or probiotics for algae, to increase microalgal survival by two-fold when under attack by rotifiers or chytrids in mass algal cultures.

According to Stuart, rotifiers and chytrids are the common culprits of algae grazing. And by using probiotic bacteria to increase algal resistance against these grazers, Stuart estimates a 5 to 10% increase in annual productivity. “The proposed tool has several advantages over the baseline, including minimal risk of pest evolution, tailored microbiome diversity to increase ecosystem resilience and productivity and probiotics that can increase algal productivity and outgrow pests,” says Stuart.

“We need to establish big algae farms to expand the future of algal biofuels,” says Pienkos. “We literally need hundreds of algae farms situated in areas around the U.S. where there is open land, some light and water availability and carbon dioxide availability.”

Overall, the U.S. needs the same amount of algae farmland comparable to the acreage the U.S. plants corn on today. And keeping those algal ponds/farms safe is a first step to commercialization. But the area of algal biofuels is ripe for innovation.

Two-pronged approach
The importance of open ponds for algae research isn’t unnoticed, as seen in Lawrence Livermore’s upcoming work on pond crashes. And, in fact, most industrial companies looking to commercialize algal biofuels use open ponds for their research and cultivation, as the technology has been tried-and-true for decades. Yet, the issue of contamination by undesirable algae strains still looms over the technology. However, Cellana, a San Diego-based developer of algae-based bioproducts, looks to produce algal biofuels in a new way.

The company’s approach presents a different way to growing algae biomass that opens research into multiple types of species never grown at the commercial-scale before. “Our approach relies on what products we want to make, and finding the right strain(s) that haven’t been produced at industrial scale before to address those products,” says Martin Sabarsky, CEO, Cellana in an interview with R&D Magazine. “This is an overall 180-degree flip on R&D and product development that has been done to date in algal biofuels research.”

The technology, called ALDUO, relies on closed-culture photobioreactors (PBR) with open ponds in a two-stage process. “Most attempts of scaling-up algae production use a PBR or open pond individually, not coupled,” says Sabarsky. “PBRs by themselves are generally unable to produce algae at an acceptable rate and tend to be too costly to be commercially viable for commodity products.”

With a large production plant in Kailua-Kona, Hawaii, Cellana has access to unique and naturally occurring algae strains from the Univ. of Hawaii, in addition to strains collected in Hawaii, that have been selected for high production of algae oil and rapid growth under targeted commercial production conditions. And the ALDUO process works where, first, the PBR is used to maintain constant conditions that favor continuous cell division and prevent contamination of the culture by other organisms.

Image: Cellana“The PBR is like a thin-film bag that protects the crop and culture, but still allows light to pass through so photosynthesis can be used in production,” says Sabarsky. “Continuous to semi-continuous production is happening in these protected PBRs, where you are only growing the strain of algae you want. You aren’t subjecting or exposing that strain to any other species that would affect your crop.”

In the second step, the algae is transferred, at dawn, after growing in the PBR for a few days, without contamination, to an open pond system of nutrient-depleted culture medium. The open pond is a paddlewheel-driven, recirculating raceway, fitted with a durable plastic liner. The goal is to expose the cells to nutrient deprivation and other environmental stresses that lead to synthesis of products, such as oils for nutraceuticals and biofuels.

After two or three days, the algae cells are concentrated by gravitation into a slurry, excess water is removed and the mixture is further concentrated. “The wet biomass is then dried,” says Sabarsky. “And that dried algae biomass can then be used as a supplement for aquaculture hatchery feeds or functional foods. If the components contained within the algae are desired instead of whole algae, the algae oils, or other components, can instead be extracted for nutraceuticals, animal feeds, biofuels or other desired products.”

“We pride ourselves in cutting our algae production into multiple products and maximizing the value of the entire barrel of algae, rather than just going after the low-value products like fuel,” says Sabarsky. “And by doing this, we will be able to see, in the near future, price-competitive crude oil and fuels, but also high-value products.”

Four fuels are better than one
Algae naturally makes oil, and they are quite good at it. And this has intrigued people as a replacement for biodiesel for over 60 years. However, another approach towards algal biofuels is producing ethanol instead of biodiesel.

Algenol, Fort Myers, Fla., entered the algal biofuels arena in 2006 trying to produce ethanol, not biodiesel. “If ethanol were made directly inside the cell, then it would leak out of the cell and evaporate from a culture,” says Paul Woods, Founder and CEO of Algenol in an interview with R&D Magazine. “So that was the impetus of Algenol 10 years ago.”

Making ethanol that leaves the cell is obviously different than making a heavy oil trapped inside a cell. But the company’s original approach back in 2006 wasn’t that different as they used a horizontal closed and sealed bioreactor. There algae wasn’t cultivated in a pond, but it was still produced horizontally. “And, at that point, we had made about 3,600 gallons of ethanol a year; which considering corn ethanol does 420 gallons a year, we are a world leader,” says Woods.

However, that number was still far from the company’s goal of 6,000 gallons per year. And, in 2010, Algenol embarked upon an important evaluation. The company wanted to know why they weren’t getting the numbers they wanted and why they weren’t scaling up the way they wished to. “And I think this evaluation forever separated us from the competition,” says Woods. “We had the man power and money to critically examine the question of why companies fail to scale-up. And when we really examined the problem, we found the true problem with commercialization and industrialization set us apart.”

Upon switching their production method from a horizontal to vertical process, Algenol began to overcome the problems commonly seen in commercialization and scale-up. Horizontal systems can never address light distribution, and when Algenol moved to a vertical panel system it addressed this problem as algae don’t want 2,000 microEinsteins of direct sun, they want 300. “And our technology really addressed these issues of heat dissipation, light distribution and photoinhibition, and it did so simultaneously,” says Woods.

Algenol’s DIRECT TO ETHANOL technology uses sunlight, algae, non-arable land and carbon dioxide to produce ethanol and spent algae that can be converted into other biofuels. The technology employs enhanced blue-green algae (cyanobacteria) and photosynthesis to convert carbon dioxide and seawater into pyruvate and then into ethanol and biomass.

Image: AlgenolThe heart of the company’s technology is a proprietary flexible plastic film PBR that facilitates product creation and collection. According to Algenol, the plastic used for the PBR construction is engineered and enhanced with resins and other features designed to optimize a variety of performance metrics. Each individual PBR consists of ports for ethanol and biomass collection and the introduction of carbon dioxide and nutrients.

The technology works where gravity facilitates the collection of ethanol and spent algae from the PBRs and Algenol’s Vapor Compression Steam Stripping technology further purifies the ethanol for downstream processing using standard distillation and, potentially, novel energy-limiting membrane technologies producing fuel-grade ethanol. “Overall, the process has a carbon footprint that’s 80% less than that of gasoline,” says Woods.

Algal biomass collected following the ethanol production provides the feedstock for the biomass-to-hydrocarbon fuels process. “The biomass is dewatered before it’s fed into a hydrothermal liquefaction (HTL) unit,” says Woods. “The primary output from the HTL unit is a green crude oil. And this crude oil is upgraded in a hydrotreater unit to a hydrocarbon product that contains a mixture of liquid hydrocarbons in the range of diesel, jet and gasoline fuels.”

“This is what sets Algenol apart. We make four fuels. And this is far more economic than making one,” says Woods.

In addition to making four fuels, the company can do this for as little as $1.30/gallon. “At this day and age, petroleum prices are very low, but at $1.30/gallon we can still be profitable and bring the benefits of algal biofuels to customers,” says Woods.

And even though Algenol has produced algal biofuels at the cheapest price, Woods sees a huge benefit to making it for $1.20 or $1.00. “R&D is key to this goal,” says Woods. “And, ultimately, our key to success was R&D and optimizing the process both upstream and downstream.”

Conclusion
And while for some companies might still be 10 years out on the commercialization of algal biofuels, the research is there for innovation, and many companies are making great strides to near-future commercialization. The truth remains that if petroleum prices keep their upward climb, products like algae biodiesel will have value, and will be both cost-competitive to public and cheap to produce.

• CONFERENCE AGENDA ANNOUNCED:

The highly-anticipated educational tracks for the 2015 R&D 100 Awards & Technology Conference feature 28 sessions, plus keynote speakers Dean Kamen and Oak Ridge National Laboratory Director Thom Mason.  Learn more.

Advertisement
Advertisement