The city of Aspen will restart its efforts next week to drill a test well assessing the potential for geothermal energy more than 1,000 feet below the surface.
Aspen officials announced Wednesday that they had reached a deal with Dan’s Water Well and Pump Service to continue work that started in the fall of 2011. At that time, the California-based contractor drilled to 1,080 feet beneath the surface of the Prockter Open Space parking lot, but did not reach water.
Twice since then, in the spring and fall of 2012, the city had hoped to resume drilling the test well, but could not because of delays and complications in reaching an agreement with the drillers. The work is restricted to the off-season, primarily because of concerns from neighboring homeowners about their ability to rent their properties if there is industrial activity nearby.
The contractor will begin setting up in the parking lot across from Herron Park on Monday, and will start drilling by Wednesday or Thursday, according to a city press release. Dan’s drillers will attempt to reach 1,500 feet below the ground, and will stop if water is not found by that point, per the agreement with the city. They are required to be off the site by May 27.
The work will take place between 7:30 a.m. and 5:30 p.m., Monday through Friday, and 9 a.m. to 5 p.m. on Saturday. The drillers will have to abide by normal city construction, noise and encroachment regulations, according to Jeff Rice, the city’s utilities efficiency manager who is overseeing project operations.
Historical accounts from Aspen’s mining days reported unusually hot underground conditions. In 2008, the city commissioned a study that found the temperature of underground water in Aspen ranged from 90 to 140 degrees.
To heat or cool buildings with geothermal energy, 100-degree water is required. To generate electricity, the city would need water of at least 220 degrees.
Aspen has already spent about $179,000 on the project, including the initial consultant’s study, and received a $50,000 grant from the Governor’s Energy Office for the work. The total budget for the project is $273,000.
The project has been controversial, due to its six-figure budget, uncertainty over whether it will bear any fruit, and concern from nearby homeowners about drilling noise and impacts.
If geothermal-worthy water is found, the city would continue conducting tests, potentially drill more test wells and then formulate a strategy for developing the energy into a resource that could benefit the public, Rice said.
If the well comes up dry, that will likely be the end of the large-scale geothermal experiment, Rice said.
Council members who responded to requests for comment said they like that the city is pursuing an aggressive alternative energy strategy, but geothermal should not be pursued at any cost.
Councilman Steve Skadron noted that private developments regularly seek to incorporate geothermal, so he is interested to see if the resource can be tapped on a larger scale.
“If you simply consider the short-term dollar costs, you may be missing an opportunity,” Skadron said. However, he said he would not support allocating any more funding to the test-well project than what has already been approved.
Councilman Torre said he has his “fingers crossed” that the project will be successful, but he remains skeptical about the city’s ability to develop geothermal into a public heating or electricity utility.
“If it’s successful, it is worth the risk,” he said.
Heading beneath the surface of Aspen, drillers first encounter an “alluvial” layer of rock and dirt deposited over millennia by glaciers, according to Rice, who said the material is relatively loose. Somewhere around 300 feet, the harder Belden layer is encountered, while around the 1,000-foot mark, drillers are hoping to reach the Leadville formation, where they think the water might be.
The existing 1,080-foot-deep hole was plugged with a soft concrete mix after drillers left the site in December, 2011, Rice said. They will have to make their way through that first before probing any new depths. Drillers will also be more proactive about “casing” the well, by inserting steel or plastic piping to hold the hole’s structure as they go, Rice said.
The drilling contractor is accustomed to drilling 24 hours a day, which is more efficient since the equipment doesn’t have to be stopped and started back up, Rice said. The company expressed its desire to do that here, but was informed that such a plan would not be tolerated in Aspen.
“That was not even a negotiation point,” he said.
Crews will be required to place sound-blocking paneling around the site to minimize the noise and contain the equipment, Rice said. The city is in the process of notifying the neighbors who live within 350 feet that the work is about to start again.
“When we get to the bottom, we will be happy one way or another,” Rice said. “I just hope we find the temperatures to justify that the whole effort wasn’t fruitless.”