Justification

This project evaluates the prospects for the large-scale cultivation and harvesting of algae followed by its conversion to various biofuels. Many companies and research teams in the U.S. and abroad have recently entered the field of algae biofuels but with limited expertise and experience. Many rely on optimistic assumptions dating from the late 1980s. Our research team will carry out an independent integrated assessment of the technological, engineering, energy balance, and environmental aspects of algae-based biofuel (in particular algae oil). During the course of this one year study we will consider net energy analysis, water/land resources available in the U.S. for such systems, regulatory issues (in particular use of GMOs), and related topics. This work will cover the most crucial issues in algae fuel technology and economics, namely (a) biotechnology to achieve high productivity, (b) the engineering design of large algal mass culture systems, (c) the harvesting of the algal biomass, and (d) biofuels production techniques. The limiting factors in the involved processes will be identified and recommendations for targeted research will be made. In addition to the biotechnological aspects, engineering, resource, economic, and regulatory issues will be investigated.

At present, two major technologies are being considered for cultivation of biofuel microalgae - closed photobioreactors and open ponds. For open pond systems, the literature is based mainly on work that was carried out by DOE under the Aquatic Species Program - most technical analysis originated in a single source. These early assessments rely on optimistic forecasts for improvements in algae productivity with improved strains, low cost harvesting technology, and use of large, low cost pond systems. For closed photobioreactor systems, which are currently the main focus of private industry, a number of recent publications discuss engineering designs and present some economic analyses – however less information is available than for pond systems. Both approaches, ponds and photobioreactors, are used commercially to produce high value algae products, though these systems are small in scale compared to what would be needed for microalgae biofuels production. Analyses conducted in this project will evaluate current practices and earlier engineering cost analyses for such systems  to arrive at an independent and realistic technical assessment of algae biofuel production potential and its economic attractiveness. The assessment will be based on personal practical R&D experience in this field, on the scientific and technical literature, and on novel analysis. 

Our team members have extensive experience with bottleneck issues in algae biofuels production and will make recommendations on target areas where EBI researchers could make substantial headway in the coming years. Important additional input will be gained in discussions with invited experts during two one-day review meetings, one focusing on engineering and the other on biology. The expert panels will include UCB/LBNL and outside experts from academia, successful algae biotechnology firms, oil and chemical companies, and other National Laboratories.  The panels will provide comment, input, and guidance to this project and recommendations for future development of this technology.

Specific topics to be covered in the project final report include :

1. Productivity and Fundamental Science. The high productivity, low cost and carbon sequestration potential of algae mass cultures is the primary incentive of these systems for biofuels production. We will review the basic literature, and existing productivity data and arrive at realistic projections for algae oil productivities in the near- and long-term. Feasible approaches for achieving improved productivities will be evaluated.

2. System and Engineering Design. Two technologies, closed photobioreactors and open ponds, have fundamentally different attributes. The current experience in both areas will be reviewed. We will review the prior economic analyses and develop updated capital and operating cost estimates.

3. Algae Mass Culture and Harvesting. After issues of productivity and cost of cultivation have been addressed - the ability to reliably grow algae in mass culture within large systems and to harvest algae affordably need to be developed. We will discuss these challenges, including invasion by “weed” algae, grazers, etc., and describe ways of harvesting algae in low-cost systems. We will assess the potential for overcoming both problems in an economically feasible way through additional focused R&D.

4. Biomass Processing to Biofuels. The nature of the oil produced by algae, the extraction of the oil, and its processing to high quality biodiesel all require further study. Alternatives such as ethanol production from algae starch and methane from residual biomass will also be reviewed.

5. Energy Balance Issues.  Fundamental to any biofuel process is that the energy output be a multiple of the process energy used in its production. We will review the available information and develop detailed energy analyses for such systems.

6. Resources Issues – Water, CO2, Nutrients, Land.  There are projections that algae systems covering in a small corner of the southwest deserts could provide all the transportation fuels required by the U.S. We will review these estimates based on the current realistic resource input costs for water, CO2, nutrients, and land. Algae culture using brackish water, saline water  and wastewater will be compared.

7. Regulatory Issues.  Regulatory issues related to water use, disposal of wastewaters (e.g. blowdown), land use, and air pollution will be reviewed. In addition, regulatory and safety issues related to genetically-modified algae will be reviewed.