Amid talk of parking lots and walking distance, another factor in the debate over where to build the Hancher/Voxman/Clapp complex lies underground in the tunnels and pipes branching from the UI Power Plant and in the subterranean possibility of geothermal energy.

University officials are considering two locations for the complex, which was heavily damaged during last year’s flood — one site west of the river, near Hancher’s original site, and another downtown.

The proposed site on west of the river would provide enough land to support geothermal technologies, similar to the one used in the UI’s new Beckwith Boathouse.

The downtown site presents another possibility — 100 percent renewable energy using biomass.

“People can have a misplaced focus,” he said. “The key is to take the energy people have and ensure it supports the wider-scale process.”

Geothermal fields, which would only be possible at the West Side site, involve laying pipes approximately 10 feet below ground and can incorporate digging wells up to 100 feet deep.

This provides a base temperature for heating and cooling, but electricity would still be required to run heat pumps, said Glen Mowery, the UI director of utilities and energy management for UI Facilities Management. And the pumps could present maintenance challenges, he said.

Geothermal fields can take up a wide swath of land, which is one reason it couldn’t work at the downtown location, Ratner said.

“A house with geothermal utilities can require about a quarter of a football field, while a building the size of Hancher would require numerous football fields,” he said.

Geothermal energy is a green technology but is less efficient than the UI’s central utilities, said Rod Lehnertz, the director of planning, design, and construction for UI Facilities Management.

The boathouse’s distance from central utilities justified using geothermal technology. But officials do not yet know if the distance of West Side location for Hancher would justify using separate utilities.

The Power Plant runs at approximately 85 percent efficiency, Ratner said, a level that is not matched by many other green technologies, especially when they are limited to individual buildings.