Red-hot greenhouse  

The Durango Herald has an article on using geothermal energy (via hot springs) to heat greenhouses and provide other services in Colorado - Red-hot greenhouse.

The scalding mineral water that bubbles up from deep within the earth here to sustain spas, heat public buildings and de-ice sidewalks is scheduled to grow vegetables soon.

"The idea of using geothermal heat in greenhouses has been floated for 20 years," Michael Whiting, director of the land trust, said during a tour of the garden site last week. "We'll be able to grow crops year-round, and by adding a solar system to extend daylight hours, we could grow tropical fruit.

"Current circumstances - weak economy, high cost of fuel, interest in renewable energy and a shift in the national culture - could mean it's the right time."

A Web site of the Governor's Office of Energy Management and Conservation lists only one other site in Colorado where greenhouses are heated with geothermal energy - a grower of potted plants near Mount Princeton.

The project here will consist of four or five greenhouses on 2 acres donated by the town in Centennial Park at the confluence of the San Juan River and McCabe Creek.

Mineral springs in the region were treasured for therapeutic qualities by Native American tribes centuries before the site was discovered by military expeditions, miners and other settlers who arrived in the 1860s. Today, the water that gushes from artesian wells at temperatures of 130 to 150 degrees has been harnessed for other purposes.

Because mineralized water can't be used in distribution pipes, the town operates a heat-exchange system. The system strips heat from the mineralized water and transfers it to a fresh-water loop into which customers tap.

About 40 businesses and public buildings, including schools and the Archuleta County courthouse, already are tied into the system, Town Manager David Mitchem said. Other businesses, including spas, have their own geothermal systems, he said. The town recovers its costs on the system, which dates to 1982, Mitchem said. It's not intended to be a money maker. Town customers, who are on meters, pay 60 cents a therm, but the greenhouse project will not be charged.

The cost of the greenhouses as well as space for packaging and warehousing exceeds $500,000, with about $300,000 contained in the federal 2010 appropriations bill, Whiting said. Local businesses have pledged free in-kind contributions.