Algae as a Feedstock for Biofuels: An Assessment of the State of Technology and Opportunities. Final report. May 2011.

Algae as a Feedstock for Biofuels. Joint Summary report of IEA-AMF Annex XXXIV-2 and IEA Bioenergy Task 39.

Background

Background There has been a recent worldwide reemergence of interest in pursuing research and development (R&D) of algae as a feedstock for biofuels, and many R&D initiatives are under way around the world as researchers, governments, and policy makers become aware of the considerable potential that algae possess. It can be expected that these various initiatives will take a number of different approaches as researchers search for answers to the challenges that algae-derived fuels face. Some pathways will be deemed unsuccessful for large-scale production, whereas others will produce high-quality results. It is important at this point to take inventory and assess the many various activities and also to try to develop recommendations about the most promising pathways to success in producing large quantities of transportation fuels from algae, which may help policy makers reach wise decisions about which areas of effort to support.

Results and Reports

The information presented in this study strongly supports that algae have potential as a feedstock for biofuels. Depending on their composition, different algae species may be suitable for a range of biofuels. For example, lipids in microalgae may be a source for production of biodiesel and other oil-based transportation fuels. Macroalgae (seaweeds) may be fermented to produce ethanol, or anaerobically digested to create methane. In these processes, algae take up carbon dioxide (CO₂) from the atmosphere during their growth, and the same amount of CO₂ is released when the biofuel is used in vehicles. Other microalgae and cyanobacteria are able to produce hydrogen in a process called biophotolysis where the algae are not consumed. All options show the potential for closed CO₂ cycles, excluding the fossil energy consumed in the total (well-to-wheel) fuel chain. Another advantage of these fuels is their compatibility with existing vehicles. For instance:

• Biodiesel can be used in diesel vehicles;
• Ethanol can be blended with gasoline (to an extent) for use in internal combustion engine (ICE) vehicles;
• Methane can be used in compressed natural gas (CNG) vehicles;
• Renewable gasoline, diesel, and jet fuel can fuel traditional ICE vehicles, diesel vehicles, and jets, respectively; and
• Hydrogen can be used in fuel cell vehicles or hydrogen ICE vehicles.

In addition, rates of algal biomass productivity per hectare can be more than ten times higher than are rates for terrestrial energy crops. Last but not least, algae can be cultivated at sea or on nonarable land, so there is no competition with current food production. The final draft report, entitled Algae as a Feedstock for Biofuels: An Assessment of the State of the Technology and Opportunities, was completed and delivered to the contributing member countries in December 2010. Feedback was received and incorporated in January 2011, and the report is being prepared for publication.  

In addition to preparatory document and final report, a joint summary report with IEA Bioenergy Task 39 is published.