Download the Algal Biofuels Roadmap draft document - Sandia

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Under Aquatic Species Program subcontracts, demonstration-scale outdoor microalgal
cultivation was conducted in California, Hawaii, and New Mexico (Sheehan et al., 1998).
Of particular note was the Outdoor Test Facility (OTF) in Roswell, N.M., operated by
Microbial Products, Inc. (Weissman et al., 1989). This facility utilized two 1,000 m 2
outdoor, shallow (10-20 cm deep), paddlewheel-mixed raceway ponds, plus several
smaller ponds for inocula production. The raceway design was based on the ―high rate
pond‖ system developed at UC Berkeley. The systems were successful in that long-term,
stable production of algal biomass was demonstrated, and the efficiency of CO2
utilization (bubbled through the algae culture) was shown to be more than 90% with
careful pH control. Low nighttime and winter temperatures limited productivity in the
Roswell area, but overall biomass productivity averaged around 10 g/m 2 /day with
occasional periods approaching 50 g/m 2 /day. One serious problem encountered was that
the desired starting strain was often outgrown by faster reproducing, but lower oil
producing, strains from the wild.
Several resource assessments were conducted under the Aquatic Species Program.
Studies focused on suitable land, saline water, and CO2 resources (power plants)
primarily in desert regions of the Southwest United States. Sufficient resources were
identified for the production of many billions of gallons of fuel, suggesting that the
technology could have the potential to have a significant impact on U.S. petroleum
consumption. However, the costs of these resources can vary widely depending upon
such factors as land leveling requirements, depth of aquifers, distance from CO2 point
sources, and other issues. Detailed techno-economic analyses underlined the necessity for
very low-cost culture systems such as unlined open ponds. In addition, biological
productivity was shown to have the single largest influence on fuel cost. Different cost
analyses led to differing conclusions on fuel cost, but even with optimistic assumptions
about CO2 credits and productivity improvements, estimated costs for unextracted algal
oil were determined to range from $59-$186/barrel (Sheehan et al., 1998). It was
concluded that algal biofuels would never be cost competitive with petroleum, which was
trading at less than $20/barrel in 1995. DOE estimated at that time that the cost of
petroleum would remain relatively flat over the next 20 years. (Although, as we now
know, the energy landscape has changed dramatically in the intervening 14 years.)
Overall, the Aquatic Species Program was successful in demonstrating the feasibility of
algal culture as a source of oil and resulted in important advances in the technology.
However, it also became clear that significant barriers would need to be overcome in
order to achieve an economically feasible process. In particular, the work highlighted the
need to understand and optimize the biological mechanisms of algal lipid accumulation
and to find creative, cost-effective solutions for the culture and process engineering
challenges. Detailed results from the Aquatic Species Program research investment are
available to the public in more than 100 electronic documents on the NREL Web site at
www.nrel.gov/publications .
Research from 1996 to Present
Since the end of DOE‘s Aquatic Species Program in 1996, federal funding for algal
research in general has been limited and intermittent. Federal funding is split between
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