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Advanced biofuels

ExxonMobil continues to fund and conduct research on advanced biofuels. This work is part of our many investments in new technologies with the transformative potential to increase energy supplies, reduce emissions, and improve operational efficiencies.

We are funding a broad portfolio of biofuels research programs including our ongoing efforts on algae as well as programs on converting alternative, non-food based biomass feedstocks, i.e. cellulosic biomass, to advanced biofuels. We believe that fundamental technology improvements and scientific breakthroughs are still necessary in both biomass optimization and the processing of biomass into fuels. Specifically, scientific breakthroughs are needed to ensure that advanced biofuels can be scaled up economically and produced with the desired environmental benefit of lower life cycle greenhouse gas (GHG) emissions. In this type of breakthrough research, clearly understanding the challenge and breaking it down into manageable questions that can be addressed through science are the first crucial steps towards finding solutions.

Scientists and engineers at universities, government laboratories, and companies are investigating a wide range of feedstocks and processes to develop advanced biofuels. We are working with some of these leading researchers and have designed our research portfolio to progress the science that we feel will be needed to deliver advanced biofuels with environmental benefits.

Our advanced biofuels research portfolio includes joint research collaborations focused on algae-based biofuels with Synthetic Genomics, Inc. (SGI), Colorado School of Mines and Michigan State. We are also exploring a variety of biomass conversion processes that could be used with non-food based feedstocks such as whole cellulosic biomass, algae feedstocks and cellulose-derived sugars. These programs are being carried out currently with Renewable Energy Group (REG), Iowa State University, Northwestern University and the University of Wisconsin.


Benefits of using algae

There are numerous benefits of using algae for biofuels production. Algae can be cultivated on land unsuitable for other purposes with water that can’t be used for food production. In addition to using non-arable land and not requiring the use of fresh water, algae could also potentially yield greater volumes of biofuels per acre than other sources. We also know that algae can be used to manufacture biofuels similar in composition to today’s transportation fuels.

In addition, growing algae can provide an environmental benefit. Algae consume CO2 and have the potential to provide GHG mitigation benefits versus conventional fuels. In 2012, researchers from MIT, ExxonMobil and SGI published an assessment of algal biofuels in the peer-reviewed journal Environmental Science and Technology, which concluded that if key research hurdles are overcome, algal biofuels will have about 50% lower life cycle greenhouse gas emissions than petroleum-derived fuel. 

In contrast, there is a robust debate in the academic research community regarding the carbon footprint of first generation biofuels, which the EPA defines as those generated from edible crops (such as corn). Many peer-reviewed papers in the scientific literature suggest that the direct life cycle GHG emissions are lower than fossil fuels, but that indirect consequences of first generation biofuel development, including changes in forest and agricultural land use change, may result in higher total GHG emissions than petroleum-derived fuels.

For these reasons, ExxonMobil is pursuing research into second generation biofuels to determine how they may best fit into our energy future. Second generation biofuels are defined as those produced from non-edible crops, crop residues, or biologically generated gas and therefore do not take away from the total food supply. Examples include algae, corn stover, switchgrass or methane emitted from microbial activity in landfills.

How algae grow

Algae can provide a diverse and highly desirable non-food source of the important renewable molecules that can be used to produce second generation biofuels. Some strains of algae can be optimized to produce bio-diesel precursors. Other algae strains can be optimized as a source of fermentable sugars, with compositions similar to those derived from corn kernels that are used to manufacture first generation biofuels like ethanol.

Basic algae biology research with Synthetic Genomics

Today, ExxonMobil and SGI are carrying out a basic research program to develop advanced biofuels from algae. Our objective is to develop advanced algae biofuels options and identify the best pathways to make these groundbreaking technologies available to consumers. The program builds off of the many insights we have obtained and the progress we have made since we announced our initial alliance with SGI in 2009.

We face some significant technical hurdles before biofuels production from algae will be possible at a significant commercial scale. To overcome these challenges, we are working to answer some basic questions such as:

  • Why do algae utilize a relatively small amount of available light energy?
  • What tools can be used to improve light utilization efficiency of algae and to improve production characteristics?
  • How do you develop an organism that will produce significantly more bio oil?

The central challenge is that algae naturally harvest significantly more light than they can effectively convert to biofuels. Only a fixed amount of light hits the surface of a pond, and our goal is for the algae to use this light as efficiently as possible. The amount of wasted sunlight varies greatly depending on the algae species and growth conditions, but can be as high as 80 percent or more. ExxonMobil and SGI are conducting fundamental research to decrease the amount of wasted sunlight and increase biomass productivity by improving the photosynthetic efficiency of individual algae cells. To achieve this objective, the SGI team is working to engineer algae cells that will absorb only the amount of light that they can effectively use.

Algae biofuels research and development is a long-term endeavor. We have learned a lot since ExxonMobil and SGI began working together, and we continue to build the biology tools, capabilities and understandings that are necessary to overcome the technical hurdles.

The challenge of scale

According to Vijay Swarup, Vice President of ExxonMobil Research and Engineering Company, “We know certain types of algae produce bio-oils. The challenge is to find and develop algae that can produce bio-oils at scale on a cost-efficient basis.”

It would require a significant amount of algae to produce enough fuel to satisfy even a small portion of U.S. road transportation fuel demand. Population and economies will continue to expand along with energy demand and CO2 emissions. At ExxonMobil, we recognize that an integrated set of solutions will be required to increase efficiency, expand supply and mitigate emissions. Technology breakthroughs will be critical and algae-based biofuels could contribute to this set of solutions.

The ultimate goal is to have algae bio-oils processed in our refineries to supplement supplies of conventional gasoline, diesel, aviation fuels, and marine fuels.

What’s Next?

ExxonMobil continues to fund and conduct research on advanced biofuels as part of our many investments in new technologies with the transformative potential to increase energy supplies, reduce emissions, and improve operational efficiencies.

Pursuing this path involves considerable investment of time, money, and scientific expertise in order to address the significant challenges associated with the development of economic, large-scale advanced biofuels. Further, predictions on success are difficult and depend directly on the pace of technological innovation. It could potentially take decades or more for advanced biofuels to reach a scale that would significantly benefit the transportation fuels sector.

We continue to evaluate our best options for continued algae biology research as part of our broader portfolio of biofuels research and development programs beyond algae.

  • ExxonMobil's research into photosynthetic efficiency provides the fundamental insights used to overcome obstacles to increasing biomass productivity.

  • SGI is employing synthetic biology techniques and exploring other fundamental science to develop highly productive algae strains.

Cellulosic Research with REG

ExxonMobil has signed an agreement with Renewable Energy Group (REG) to study the production of biodiesel by fermenting renewable cellulosic sugars from sources such as agricultural waste. REG has developed a patented technology that uses microbes to convert sugars to biodiesel in a one-step fermentation process similar to ethanol manufacturing. The ExxonMobil and REG Life Sciences research will focus on using sugars from non-food sources.

REG has a long history of innovation in the production of advanced biofuels from lower carbon, waste feedstocks. Through the research, the two companies will be addressing the challenge of how to ferment real-world renewable cellulosic sugars, which contain multiple types of sugars, including glucose and xylose, but also impurities that can inhibit fermentation.

Our first challenge is to determine technical feasibility and potential environmental benefits during the initial research. If the results are positive, we can then take the next step and explore the potential to expand our efforts and explore scalability.

University partnerships

Colorado School of Mines / Algae Biofuels

ExxonMobil and Colorado School of Mines have established a joint research collaboration – led by Mines Chemistry and Geochemistry Associate Professor Matthew Posewitz, who has been working in the algae field for 13 years – focused on developing fundamental new insights into photosynthetic processes and carbon fixation in algae. These new insights will provide better understandings of the scientific and technical challenges involved in producing biofuels from algae.

Michigan State / Algae Biofuels

ExxonMobil has a joint algae biofuels research collaboration with Michigan State, which is focused on advancing the fundamental science of algal photosynthesis. Prof. David Kramer, MSU’s John Hannah Distinguished Professor in Photosynthesis and Bioenergetics, is leading the effort. The overall goal of the partnership is to improve the efficiency of photosynthesis in algae in order to increase biofuels production.

Iowa State / Biomass Fast Pyrolysis

The ExxonMobil Biofuels Program at Iowa State University focuses on fundamental scientific and engineering questions about the chemical and physical processes that occur during the pyrolysis of biomass. Iowa State researchers have been studying fast pyrolysis for more than 15 years.

The ExxonMobil projects will be led by four researchers. Robert C. Brown, a professor in Mechanical Engineering and director of Iowa State’s Bioeconomy Institute, and James Michael, an assistant professor of mechanical engineering, will study fundamentals of pyrolysis. Brent Shanks, a professor of Chemical and Biological Engineering and director of the National Science Foundation Engineering Research Center for Biorenewable Chemicals, and Xianglan Bai, an assistant professor of mechanical engineering, will study processes that influence bio-oil stability and quality.

Northwestern University / Biomass Fast Pyrolysis

The ExxonMobil Biofuels Program at Northwestern University focuses on the use of advanced mechanistic modeling to probe the technical challenges and potential opportunities associated with biomass fast pyrolysis. Prof. Linda J. Broadbelt, Sarah Rebecca Roland Professor and Chair of Northwestern’s Biological and Chemical Engineering Department, is leading the work. Previous research in her group developed a model for pyrolysis of cellulose, one of the key components in cellulosic biomass feeds. This model is currently being extended to enhance understanding of the more complicated components in cellulosic biomass feeds.

This research will help identify reaction pathways and mechanisms occurring during pyrolysis and may provide insights for suppressing undesirable reactions.This fundamental understanding is crucial to determining the potential of pyrolysis technology.

University of Wisconsin / Biomass Upgrading

ExxonMobil has established a joint research program on biomass upgrading processes with the University of Wisconsin. The program is led by Professor George Huber, a leading investigator and innovator in biomass conversion. The program focuses on converting the initial products of biomass decomposition to more valuable final products. For instance, sugars or sugar-related compounds can be produced from biomass via primary decomposition processes such as fast pyrolysis or treatment with acid and enzymes. This program with Wisconsin is assessing catalytic reactions for transforming these sugars into hydrocarbon fuels such as gasoline and diesel.