New Mexico Geological Society Annual Spring Meeting — Abstracts

The geothermal resource of Presidio County could supply many times the county's electrical and direct-use needs if developed. Geothermal power would also increase resiliency and incentivize businesses to settle and expand in the county. Presidio County clearly has substantial, undeveloped geothermal resources. These resources could prove economically viable for development in a wide range of scenarios for electricity production, industrial/agricultural, and heating/cooling use. The economics of geothermal development are varied and (without considering any tax/credit/loan incentives, which can be substantial) range from poor to good.

The best quality resource (the Border region) is a strip approximately 16km (10 mi) wide along the border with Mexico running from Redford to the NW corner of the county. The thermal gradients in the zone are quite high (on the order of 200-300°C/km), meaning the required drilling depths to reach a given temperature are relatively shallow (which in turn means lower project cost). This zone corresponds to a large percentage of the relatively low population and thus energy demand of all types.

The bulk of the county (about 2/3) is in the Interior Region. Despite the name, this area is still an excellent resource, with temperatures above average worldwide. Although drilling depths needed to reach a given temperature are deeper than the Border Region, they are still within the range of present technology, are potentially economic, and could easily support the main population center of Marfa.

The county's southeast corner, the Big Bend Region, is a relative unknown. There is a severe lack of data other than surface geologic mapping; thus, not much can be said about the potential here, though it is likely to fall within the bounds of the Border and Interior regions and therefore have significant potential. Drilling new wells in this region would be needed to improve the assessment of this zone.

Further research is proposed that would “buy down” risk to all parties.