Cost Analysis of Aquatic Biomass Systems

In 1978, Dynatech R/D Company prepared a report that analyzed the feasibility of using both macro — and microalgae systems, as well as other aquatic plants, for fuel production (Dynatech R/D Company 1978a). A major emphasis of this report was seaweed systems (“Ocean Farms”), as these were a major focus of the ERDA/DOE Fuels from Biomass Program at the time. This report concluded that macroalgae systems, based on open ocean giant floating seaweed farms, were technically and economically infeasible. The report also addressed the land-based microalgae systems, based on the report by Benemann et al. (1978) discussed in the previous section. The authors concluded that CO2 supply from power plant stack gases required “prohibitively expensive” duct work, distribution and transfer systems. It recommended further development only of emergent higher aquatic plants, such as water hyachinths and marsh plants, which can use CO2 from the air.

However, these conclusions were subjected to considerable critique. In response, a companion report was prepared that addressed “Reviewers’ Comments” (Dynatech R/D Co. 1978b). Although most of the comments related to the macroalgae systems, the conclusions regarding the microalgae process were also challenged, specifically with respect to CO2 transfer. It was pointed out that CO2 transport distances from the power plant to the ponds need not be longer than 10 km, as assumed in the Dynatech R/D Co. report and that CO2 transfer into the ponds could be both efficient and of low-cost. In other respects, including water and nutrients supply and use, the Dyantech R/D (1978a) report concluded that overall “it appears that there is a high probability that land-based aquatic biomass growth systems can be designed which are technically feasible and for which growth energetics are quite favorable.” This conclusion did “not necessarily imply economic feasibility.”

Actually, the Dynatech R/D Co. (1978a) conclusions were more positive than the opinions of some participants in this project. For example, Goldman and Ryther (1977) had earlier rejected the concept of microalgae fuel production, because, among other arguments, the water and fertilizer resources for microalgae ponds would be prohibitive. However, Oswald and Benemann (1977) countered arguments, pointing out, for example, that such a simplistic analysis failed to consider water and nutrient recycling. In this connection, Goldman (1979a, b) also reviewed the fundamental and practical aspects of microalgae biomass production, including the productivity data with outdoor pond systems. As part of the Dynatech Report, DOE published a “Topical Analysis” of aquatic biomass systems (Goldman et al. 1977), a good review of the scientific basis at the time.

I Publications:

Dynatech R/D Company, (1978a) “Cost analysis of aquatic biomass systems.” Report prepared for the U. S. Dept. of Energy, HCP/ET-4000-78-1, vol. 1.

Dynatech R/D Company, (1978b) “Reviewers comments on cost analysis of aquatic biomass systems.” Report prepared for the U. S. Dept. of Energy, HCP/ET-4000-78-2, vol. 2.

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Goldman, J. C.; Ryther, J. H. (1977) “Mass production of algae: bioengineering aspects.” In Biological Energy Conversion (Mitsui, A., et al., eds.), Academic Press, New York, pp. 367-378.

Goldman, J. C.; Ryther, J. H.; Waaland, R.; Wilson, E. H. (1977) “Topical report on sources and systems for aquatic plant biomass as an energy source.” Report to the U. S. Dept. of Energy.

Oswald, W. J.; Benemann, J. R. (1977) “A critical analysis of bioconversion with microalgae.” In Biological Energy Conversion (Mitsui, A., et al., eds.), Academic Press, New York, pp. 379-394.

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