III. C.1. Introduction

One major concern of the ASP, as for any renewable energy option being developed by DOE, is the resource potential for the technology. How large an impact will it have on future U. S. energy supplies, or, in today’s units, fossil CO2 or equivalent greenhouse gas reduction potential? This is required both by the mission of the DOE as well as the inherent need to justify budgetary decisions. However, potential contributions to fuel supplies should be only one, albeit an important, parameter in such an assessment. Other factors must also be considered, such as economics, time frame for implementation, and the possibility of success for the R&D effort. If large resource potential is the main criterion, this could result in focusing too many resources on a few technologies with a low probability of succeeding in practice.

Microalgal biodiesel is one of many different biomass energy options, extending from co-firing of wood in power plants to energy farms and a myriad of fuel conversion options (Hughes and Benemann 1997). One important attribute of microalgae systems is that they need not compete with other biomass alternatives, but must be able to use water and land resources generally not considered for crop production. Also, microalgae fuel production systems could meet other objectives, from waste treatment to salinity management. Resource potentials are important, and have been studied extensively by the ASP.

The ASP emphasized the production potential of microalgae in the southwestern United States. This choice was based in large part on the perspective that this area offered the best and largest resource potential for algal culture systems, including available saline water supplies, land area, sunlight, and CO2 sources. Each of these resources individually was projected to have a potential of many quads (1015 Btu) of energy, and overall potentials of several quads were projected (e. g., Chelf and Brown 1989). This certainly justified the emphasis by the ASP on this geographical area. In fact, a significant activity of the ASP was to document this resource potential. It was not a trivial task to assess these resource potentials. This required the development of suitable assessment techniques. This was a major accomplishment of the ASP, as reviewed in this section. However, estimating an actual resource potential is not a simple matter, as the juxtapositions of the requirements for microalgae production—water, land, CO2, and climate— are very difficult to quantitate, and would greatly reduce the resource potential estimated from single factor analyses.