Surprise Valley in Modoc County, California, where a proposed geothermal exploration project has drawn local concern. Image credits: Wikimedia Commons
The project’s California Environmental Quality Act filing describes up to 11 geothermal test wells on nine well pads. The wells would be drilled to depths of 3,000 to 5,000 feet, allowing researchers to study temperature, pressure, flow rate, and the chemical composition of geothermal fluid. The filing places the 39.5-acre site between Surprise Valley Road and County Road 13.
It also flags groundwater, tribal cultural resources, wildfire, transportation, and air quality as potential concerns.
Drilling of the Warner Mountain Energy-Exploratory 1 well (WME-E1) took place from May 15 to June 8, 2019, and reached 3,605 feet rather than 4,000 feet. Based on that modeling, the report estimates that the well could sustain its maximum artesian flow for 20 years or more, and it characterizes the reservoir as shallow and highly productive at 230°F, with productivity indices that are high by geothermal industry standards. The commission’s report Geothermal Exploratory Drilling, Surprise Valley describes a study that set out to evaluate underground temperatures and reservoir characteristics. The work included well tests, geological logging, geochemical sampling, and reservoir modeling. The above-mentioned study also notes the possibility of a hotter, deeper reservoir that merits further research. This is one reason the area has been considered suitable for geothermal development. The above mentioned Geothermal Exploratory Drilling, Surprise Valley study also covered potential uses of the resource, including power generation and agricultural use of geothermal water. Taken together, the two reports show that economic uses of the area’s geothermal resource have been studied, although the demonstration module never reached commissioning. Groundwater, cultural resources and the other concerns listed above are among the topics the environmental review of the current project addresses. SFGATE’s reporting also describes residents’ concerns about groundwater, nearby property values, and the valley’s rural character, set against the project’s potential for renewable energy and local jobs. Further development would depend on the results of exploration and review. In Surprise Valley, the economic and environmental questions are closely linked. Geothermal energy could bring economic benefits to the area, but residents are also concerned about the consequences for their groundwater, hot springs, and agricultural operations.
Earlier research established the valley’s geothermal potential Earlier geothermal exploration in Surprise Valley was funded by the California Energy Commission. However, results from a single earlier well do not guarantee the suitability of all proposed drilling sites.
It lists 15 jobs tied to the 39.5-acre site and identifies the area as industrial use under a use permit.
The filing says the project would also need three new access roads off Surprise Valley Road, while existing routes may have to be widened or surfaced to handle drilling equipment. This describes proposed activity, not a completed development. Exploration lets developers confirm that a resource could support electricity generation, and finding a suitable resource does not by itself mean a commercial power plant will be built.