Boise target: Increase geothermal heating system by 40 percent | Culture & Leisure

ByShannon J. Cortes

Dec 30, 2021

BOISE – The city of Boise is looking to expand its geothermal heating system by 40% as part of a goal to become carbon neutral by 2050.

The city pumps 250 gallons of geothermal water into 96 buildings through 21 miles of pipes. The water has a temperature of 177 degrees Fahrenheit.

City officials said geothermal heat provides about 2% of the city’s energy resources.

“Geothermal energy really provides this clean energy alternative,” said Steve Hubble, head of Climate Action, the Idaho Statesman reported.

The heated water comes from a geothermally heated water river flowing under the neighboring foothills. Experts say the water is heated by the Idaho Batholith, a massive igneous intrusion of granite that produces heat through the decay of isotopes like uranium, thorium and potassium.

Boise’s geothermal program director Jon Gunnerson said a large fault line runs through the Boise foothills and helps bring water close to the surface. Hot water is pumped from city-owned wells in the foothills to the buildings and then returned to the aquifer.

City officials have said they want to expand geothermal water use from 5 million gallons per year to 355 million gallons.

Gunnerson said anyone interested in switching to geothermal energy should contact his office. The city says the rate is competitive with natural gas prices.

“It’s kind of one of those hometown assets that (Boiséens are) really proud of,” Hubble said.

The people of Boise have used geothermal heat for about 130 years and there are four geothermal networks in the town. In addition to the city system, there is a private home heating system on Warm Springs Avenue, another state-owned that heats the Statehouse and other state-owned buildings, and a fourth operated by the department. United States Department of Veterans Affairs for its facilities in Boise.

Besides the Statehouse, Ada County City Hall and Courthouse are also heated with geothermal water.

Eleven buildings at Boise State University are also heated with geothermal water. It is the farthest point from the wells in the city system.

The water cools as it moves away from the wells, officials said, limiting the distance at which hot water can be used.

“It will be really downtown and within reach in every direction,” Gunnerson said.

Boise spokesperson Colin Hickman said the wells have a large capacity and no new production wells are planned.