There obviously must be heat under the ground somewhere near Mount Spurr, an active volcano on the west side of Alaska’s Cook Inlet. But a viable geothermal power plant on the flanks of the mountain would require a suitable underground geothermal energy source in a location where adequate heat can be pumped to a surface facility.
No doubt with that in mind, Reno-based Ormat Nevada has filed with Alaska’s Division of Oil and Gas a plan for a summer 2010 program of Mount Spurr geothermal exploration involving geophysical surveys and field mapping. If this initial work discovers a likely looking geothermal prospect the company could follow up with some “slim-hole” drilling, to determine if a viable geothermal source exists in the subsurface.
New energy resources?Ormat Nevada, a subsidiary of geothermal power company Ormat Technologies Inc., picked up 15 leases on the southern flanks of Mount Spurr in the State of Alaska’s September 2008 geothermal lease sale. Many people hope that a successful Mount Spurr geothermal project would help expand Southcentral Alaska’s energy supplies, currently heavily dependent on natural gas, into more a more diverse mix of energy resources.
The Mount Spurr geothermal leases are just 40 miles from Beluga, the nearest point on the Southcentral Alaska electricity grid. And in April the state Legislature passed a bill reducing royalty rates for geothermal energy and placing the regulation of geothermal drilling in the hands of the Alaska Oil and Gas Conservation Commission.
Ormat says that it will identify any potential geothermal drilling sites at Mount Spurr by analyzing and integrating several datasets collected during its summer 2010 exploration program.
But any drilling would require further regulatory authorization, Ormat said.
Airborne surveysOrmat says that it will start its work program in June with airborne surveys consisting of high-resolution aerial photography of the exploration area, the acquisition of LIDAR data and the acquisition of hyperspectral data. LIDAR uses an aircraft-mounted laser system to make precision measurements of landforms, while hyperspectral data involves the imaging of terrain using a very wide electromagnetic spectrum.
To achieve the necessary precision for these surveys, Ormat will place a global positioning system base station as close as possible to Mount Spurr, the company said.
In early July another airborne survey, using a helicopter, will collect about 1,550-line-kilometers of magnetic data, Ormat said.
Ground surveyingA program of ground-based geophysical surveying will start July 1 and continue through August. This program will involve using 100 stations for the measurement of magneto-telluric data and up to 400 stations for making gravity measurements.
Magneto-tellurics involves the measurement of naturally occurring, ambient electric noise emanating from the ionosphere and from distant thunderstorms — buried electrodes measure electric fields while buried electric coils measure magnetic fields, Ormat explained.
A separate team will conduct the gravity survey using a small field gravimeter to measure variations in the Earth’s gravity across the exploration area, probably travelling to survey sites with the magneto-tellurics team by helicopter.
Another team, also transported to field locations by helicopter, will conduct geologic mapping and will sample water from creeks, springs and glacial outwash. This team will likely also carry out measurements of any flows of carbon dioxide from the soil.
Based locallyThe ground mapping and survey work will be based out of either Beluga or Tyonek on the Cook Inlet coast, or from a temporary camp in the survey area, Ormat said. All company and contractor personnel will complete environmental and safety training. And the company has developed a plan for bear and wildlife interaction, including the use of dedicated bear monitors during field operations.
Ormat also said that it has been holding meetings with local community representatives, including the village of Tyonek, Cook Inlet Region Inc. and the Kenai Peninsula Borough, and with Cook Inlet Keeper and other environmental organizations. The company anticipates significant local hire opportunities, Ormat said.