This study (Maxwell et al. 1985) assessed the availability and suitability of land, brackish water resources, and climate in the southwestern United States. The objective was to “stratify the Southwestern United States into zones of varying suitability for such [microalgal] systems.” The Battelle Columbus report discussed earlier (Vignon et al. 1982) was identified as a companion effort, although it was “not directly supportive of the stratification effort… ” Climate, land resources, and water resources maps based on various process constraints and characteristics (e. g., freeze-free period, land slope, water depth) were overlayed to develop suitability maps. Because of insufficient water data, water supply was excluded from the final analysis. Available maps were also inadequate for land classification for slopes <10%.

This report includes an excellent discussion of the sources of maps and information about water, water rights, land ownerships, slopes, topography, climate, etc. Of course, in the dozen (or more) years since this research was carried out, the computer revolution has made access to this data easier or at least different. The report provides a very comprehensive review of the problem, and supplies a large amount of specific information. One interesting point is that microalgae systems will likely encroach on pasture and non-irrigated agricultural land; much of this land has low productivity and value, but is generally accessible and already generally serviced by roads and power.

A relative productivity map was developed for the southwestern United States, by combining frost-free days with insolation values. Many other such maps, including land suitability and water availability, were prepared, including a final overall suitability assessment (Figure III. C.1.). The authors proposed continuing such an assessment, pointing out the many limitations of the present study (such as water laws and rights issues) that required further studies. However, a point of diminishing returns is likely to be reached. It may be best to evaluate some very specific areas, even sites, for actual suitability for such a process. Indeed, any generic analysis may miss important details. For example, as indicated in Section III. B. from the experience at Roswell, New Mexico, that location is quite unsuitable for microalgae production, due to its short (approximately 200-day) growing season, although it appears in the overall suitability map (Figure III. C. 1.). This was likely due to insufficiently restrictive temperature criteria (freeze-free days, etc.).

I Publications:

Maxwell, E. L; Folger, A. G.; Hogg, S. E. (1985) “Resource evaluation and site selection for microalgae production systems.” Report, Solar Energy Research Institute, Golden, Colorado, SERI/TR-215-2484.

Figure III. C.1. Overall suitability map for microalgae culture in the Southwestern United States.

Zones of relative suitability for microalgae biomass production based on compositing of climate, land and water suitability maps. (Source: Maxwell et al. 1985.)