A one (1) acre cultivation equivalent means a suite of operations, including inoculation, cultivation, harvest, and processing sized with the capability to process and produce gallons of algal biofuel intermediate per day. A biofuel intermediate is a biomass-based feedstock that will serve as a petroleum replacement in downstream refining.

Low algal biomass yields are identified as a key driver of the high cost of algal biofuels because of the high capital investment projected as necessary to achieve commercial-scale volumes of biofuel. Increased yields achieved by demonstrating radical improvement and innovative alternatives to the baseline will decrease the amount of capital investment needed, better utilize fixed assets, and improve the environmental sustainability of algal biofuels.

Background. The DOE Biomass Technologies Office (BTO) began scoping activities to understand the critical technical barriers to affordable and scalable algae-based biofuels with the 2008 National Algal Biofuels Technology Roadmap Workshop. Results of that workshop, published as The National Algal Biofuels Technology Roadmap (the Roadmap), serve as guidance for DOE to identify topics needing additional research funding. (Earlier post.)

Subsequently, DOE selected four research consortia to begin a national applied research program (DE-FOA-0000123, earlier post) to address many of the technical challenges identified in the Roadmap for successful large-scale algae biomass production.

BTO further built upon the R&D activities through the funding of research projects in the Advancements in Sustainable Algal Production (ASAP) FOA (DE-FOA-0000615, earlier post). These projects, currently underway, support the development of technologies for algal biomass production that demonstrate minimal water and external nutrient inputs and establish Regional Algal Feedstock Testbed (RAFT) partnerships.

Advancements in Algal Biomass Yield. This new FOA is focused on a longer-term (up to 60 months) effort to integrate research and development on comprehensive mid-scale processes from strain development to production of biofuel intermediates. This work is intended to complement and build upon the current body of research to support enhanced algal biomass yields. The FOA establishes one comprehensive topic area encouraging integrated research that focuses on the following three main priority areas:

1. Improvements in Algal Biomass Productivity;
2. Improvements in Preprocessing Technologies; and
3. Technical Advances that Enable Integration of Algal Biomass Unit Operations.

Priority Area 1: Improvements in Algal Biomass Productivity. This Priority Area is targeted at applied research that will accelerate the development of promising algal strains and cultivation techniques that will result in increased algal biomass productivity in outdoor cultivation environments relevant to commercial scales.

BTO’s baseline analysis results show that conservative modeled productivities (13 grams per meter squared per day – g/m²/day on an annual average basis) are associated with high resource use, high costs, and high GHG emissions for algal biofuel systems. Priority Area 1 is focused on demonstrating increased algal biomass productivity that, in combination with improvements in other downstream processes, will meet the biofuel intermediate productivity goal of 2,500 gallons per acre per year by 2018.

Productivities above 25 g/m²/day are achievable in the lab and advanced biotechnology may further increase this; however, a clear barrier exists in translating laboratory success to demonstrated, scalable, outdoor cultivation environments that capture all of the variables not present in laboratory systems.

DOE expects that research conducted in the selected projects will include an iterative process whereby the results obtained from experiments in outdoor environments will be used to inform the laboratory experiments and vice versa. This continuous feedback loop is expected to expedite the lessons learned and ensure they are relevant for large scale algal biofuel production.

Improvements to increase algal biomass productivity may include, but are not limited to: advances made to systems biology approaches; gains in knowledge related to fundamental algal processes (e.g., photosynthesis); strain improvement from breeding to modification and/or genetic engineering; improvements in cultivation strategies, such as crop protection, water and nutrient management, carbon dioxide delivery and utilization, light optimization, temperature management, and seasonal succession; and cultivation infrastructure engineering to maximize biomass yields while minimizing land, capital, and operating costs.

Acceptable algae cultivation systems include open ponds, attached growth systems, and closed photobioreactors (PBRs), combinations of these systems, or other systems with similarly justifiable scalable potential.

Priority Area 2: Improvements in Pre-processing Technologies. This priority area is aimed at applied research and engineering to build and operate innovative harvesting, dewatering, and intermediate processing (e.g., extraction) unit operations that can be integrated at scale with biomass production (i.e., support appropriate volumetric flow-through); can be operated efficiently so that the energy expended does not exceed 10% of the energy content contained in the biofuel intermediate; and are low cost (both capital and operational expenditures) to scale.

There are scalable technologies/unit operations within other processing industries, such as wastewater and mining that are currently being analyzed, tested, and used in the algal biofuel industry. However, even known technologies from other industries must be researched, tested and scaled appropriately within an integrated algal system before one can state that it will work within a specific algal technology pathway or process. Pre-processing technologies can be high in capital and operating costs as well.

Priority Area 2 is focused on accelerating the development of the most innovative ideas for pre-processing technologies that can bridge the gap between laboratory scales and process relevant scales in an outdoor, real world environment and result in significant advances toward achieving a more economical process while maintaining or improving yields.

Areas of significant interest include improving extraction and fractionation of cellular metabolites, separations, parasitic energy loss (or energy return on investment), and capital and operating costs.

Priority Area 3: Technical Advances that Enable Integration of Algal Biomass Unit Operations. This Priority Area is aimed at ensuring that the integrated system is capable of meeting target yields and can be scaled and operated to produce cost-competitive fuels and products.

The foundation of this FOA rests on the application of Priority Area 3 to the first two priority areas. For example, the work performed by phycologists and biologists to engineer a particular strain for enhanced lipid-producing characteristics needs to be integrated with work performed by downstream engineers who are focused on harvesting solutions. BTO seeks to foster this type of communication upfront to streamline technology development and decrease time spent on “fatally flawed” approaches.

Performance periods. Given the duration of the effort, DOE will divide the project into performance periods. Applications to this current FOA are for Performance Period 1, with a maximum of $5 million federal share and up to a 30-month scope of work. Subject to continuation Performance Period 1 may be scaled up in a second performance period to support demonstration of the minimum FOA objective of one acre cultivation equivalent.