Before any more geothermal loops are approved on Saanich lakes, the municipality wants proof the loops won't inadvertently heat the lakes' water.

Last month, the province approved an application by property-owner Gordon Porritt to install a geothermal loop, which capitalizes on the earth's relatively stable temperature to heat or cool a house. Many environmentalists applaud the system for requiring little energy to run.

Normally, the technology is looped into a well or the ocean. Very few have been tested in lakes.

"In researching this there was no documentation on what kind of cumulative damage there could be," said Coun. Vicki Sanders in council chambers last Monday night (Nov. 24).

As chair of Saanich's environmental advisory committee, she moved that council ask the province not approve any new applications until more information is available.

Porritt plans to build a home on Prospect Lake and wants to install a geothermal loop, which works by circulating liquid through piping that runs from the lake bottom to the house.

His system will only be used during winter months, to alleviate concerns of heating the lake in summer.

Still, the community responded by filing an objection to the Ministry of Environment with concerns future system could heat the lake, causing blue-green algae and invasive frogs to flourish.

The Ministry of Environment dismisses these fears that the loop could heat the water.

"There's a low energy transfer," said Greg Kockx, operational program manager with the ministry, in September.

"They don't know that ... because they don't have that information," objected Sanders. "Even if the heat increase isn't significant at what point do we (draw the line on thermal emissions)?"

Council unanimously approved the motion with no discussion.

rholmen@saanichnews.com