A milestone was reached in the geothermal project at the state capitol as the final of two wells were dug.
The project, which began in the later part of 2010, will heat and cool the capitol building by using the Earth.
"It's an open loop system," said project manager Lance Shepherd. "We're drawing water out of one well, we're pumping it through a heat exchanger, and we're discharging it into the other side."
Shepherd said the water that is being pulled from the Arapahoe aquifer, which is nearly 900 feet below ground, is at 65 degrees. That is more than enough to heat the building in the wintertime and conversely, cool it in the summertime. He added if the building needs to be made warmer or cooler, it will not cost as much as a traditional HVAC system.
The building was in need of replacing its current heating and cooling system, Shepherd said. Parts of the system were almost 70 years old. Due in large part to a $4.1 million federal grant from the Department of Energy, Colorado was able to install the geothermal system for a price that was just $500,000 more than replacing the system with a traditional HVAC system.
Shepherd said the energy savings will more than pay off that difference. He said the cost savings is anticipated at more than $100,000 in the first year and at $160,000 annually by year 15.
"I think it is going to be something you are going to see more of in the future," Shepherd said. "But they are not sexy like wind and solar where you can see it. Because you can't see anything. It's underground."
And that was part of the appeal for the Capitol. There is not enough room on the grounds for a solar array that would power its HVAC unit and a wind turbine on the Capitol dome was just not feasible, Shepherd said.
The next step in the project will be to install test rigs to make sure the water flow is where they want it. After that, they will sink pumps into the wells and hook the system up to the Capitol building.
The project is anticipated to be online in time for the next legislative session in January.
Colorado will become the second state with a geothermal powered Capitol. Idaho is the first with a geologically-active geothermal system.
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