An initial feasibility study indicated that the area surrounding Herron Park and Prockter Open Space is likely to have significant geothermal potential. The City did not want to physically disturb Herron Park, so it selected the gravel parking lot adjacent to Prockter Open Space for the project site.
Geothermal energy is naturally occurring energy in the form of heat that is trapped below the Earth’s surface. The heat energy is produced by the Earth’s core and sometimes travels very close to the Earth’s surface by way of fissures and cracks in bedrock layers. The heat subsequently heats water that is also trapped under the Earth’s surface. Glenwood Springs’ and Conundrum’s hot springs are great examples of how water near the Earth’s surface can be naturally heated by extremely high core temperatures. Geothermal energy is virtually a free source of renewable energy. It’s non-polluting, produces no carbon emissions, and can be locally sourced.
This project has a total budget of $200,000. The City was awarded a $50,000 grant from the Colorado Governor’s Energy Office. The remaining $150,000 is from a City renewable energy fund, which is funded by Aspen electric and water utility rates.
During the project, what will be visible is a truck-mounted drill rig with a fence around it. There will also probably be noise barriers and educational signage about the project.
The test well hole will be approximately 6-8 inches in diameter and approximately 1,000 feet deep, in order to reach the bottom of the Leadville Limestone Formation. The City needs to measure and understand the geothermal gradient in the formation.
The 6-8-inch diameter is needed because the annular space between the borehole wall and the surface casing needs to be at least one inch or greater to cement the surface casing (a depth of about 40 to 60 feet most likely depending upon drilling conditions). Assuming no additional casing is needed, the minimum borehole diameter will be 4.75 to 6 inches inside the surface casing to the total depth.
The soil or “drill cuttings” will be properly disposed of on a regular basis during drilling.
The river will not be negatively affected by this project.
Noise controls will be put into place and levels at the nearest property line will not exceed 80 decibels, the City's limit for construction noise.
Will there be a sulfur smell coming from the well?
There is no odor expected to come from this project.
The test well site will either be fully restored or will be used for future monitoring, if needed. In this case, a flat, locking cap would be installed and parking and recreation would be unaffected.
Drilling of the test well is expected to take approximately 10-20 days of the total 30-45 day project. An approximate project schedule is available here.
Note: Since no hot water has been located at 1,000 feet (Day 18), additional drilling is necessary. The project is being completed as quickly and safely as possible.
This well is for testing only. It is possible that in the future it could be used as a monitoring well, but this would be completely underground. This test well will not be converted into a production well.
There are a couple reasons why this won't give us an accurate picture of Aspen's geothermal potential. First, the water in the mine shaft comes in contact with air and thus the temperature of the water will not give us a clear picture of what geothermal temperatures exist. Secondly, there is likely to be debris making it difficult to easily access the water in the mine shaft. Drilling a test well will give us much more accurate water temperature data to help determine if Aspen's geothermal resources might someday be used for heating or electricity.
Questions? Contact Sam Irmen at (970) 429-1974 or sam.irmen@ci.aspen.co.us.