SOMBA K'E/YELLOWKNIFE
The once highly touted scheme to tap geothermal heat from beneath Con Mine - subject of a highly contentious referendum three years ago - wouldn't have worked after all, city officials now say.

Mike Borden, a former senior planning engineer at Con Mine, said he had doubts about the geothermal findings at the now closed mine as soon as he heard of them. - Elaine Anselmi/NNSL photo

The city's "Geothermal Project" was deemed not feasible approximately a year after residents voted against spending up to $49 billion toward the project in March 2011. The project was rejected by a vote of 1,362 to 997 despite a high show of enthusiasm from city council, environmental groups and Yellowknife MLAs.

The plan called for water warmed by underground heat from Con Mine to be harnessed to heat 39 buildings downtown. The project would have also utilized a central district energy system fueled by wood pellet boilers and heating oil tied to the buildings through buried utilidor pipes.

"It was determined in the cost-benefit analysis that we did of building a system like that, that the heat was too low-grade for what we were anticipating," said Mayor Mark Heyck, who was a strong supporter of the project while on city council and defended it while running for mayor in 2012.

The option of harnessing the renewable resource from the now closed mine site came up in 2007 when Mory Ghomshei, a University of British Columbia mine engineering professor, reported temperature findings in mine shafts underground of around 40 C. This information was presented to the public prior to the referendum, as the city began to consider the site as a source of geothermal energy.

"We ended up holding the plebiscite when we did because there were timelines attached to some federal funding that had been awarded to the project, so we had to have our financing in place by the end of 2010/2011fiscal year," said Heyck, referring to a $14.1-million federal grant that was dependent upon residents voting 'yes.'

"We did remind the public that the plebiscite wasn't the final word whether the project was going to go forward or not, there was other due diligence we were still going to do and if at any point it didn't look like the project was going to be feasible, we would stop at that point."

The city did continue with a geothermal study, with B.C.-based Corix Utilities expressing interest in funding and operating the project in June 2011. Belgian firm Vito Engineering also came on board to study the resource, working with long-time mine staff members, such as former senior planning engineer, Mike Borden.

Glowing assessment

One year later, in April 2012, then-mayor Gord Van Tighem offered the public a glowing assessment of

Vito's report, saying geothermal had the potential to provide half the heat for the project.

Van Tighem now acknowledges the plan as originally proposed wouldn't have worked but Con geothermal still had potential for other uses, such as heating the city's water.

"Like anything, every cloud has a silver lining, just keep looking for the silver," said Van Tighem.

"The project in its initial concept was good, what happened as it developed it created questions and ultimately shelved the project. It was probably not so much the project itself, but the funding opportunities related to the problem and then the restrictions that were placed on them."

Media were not invited to the presentation of Vito's study into the geothermal levels at Con Mine, but Borden and other key players were in attendance.

"They came up with a finding at the end that, yes, there is a geothermal reserve but a very low grade," said Borden. "At that point in time, what didn't make the papers is what was said behind closed doors and that was essentially, 'this is not going to work.'"

Although Vito's report did confirm temperatures of above 30 C in some areas, Heyck said there were considerable challenges in accessing that heat.

"We found when we did our in-depth analysis of the geothermal resource and the sustainability of what is present under Con Mine, we found that at the very deepest part of the mine, the water does get fairly warm, in the high 30s or mid to high 30-degree-range," said Heyck.

"Unfortunately, when you're building a district energy system with a fairly high heating load, you need fairly large void spaces where the water is warming up and at the deepest point in Con Mine, you don't have that."

Throughout the process of studying geothermal, Remi Gervais, energy co-ordinator for the city, said the amount of available energy gradually decreased from 30 megawatts (MW), to 15 MW, to 1 MW.

"Considering the investment required, 1 MW wasn't enough to make the project viable, that's why in the last design proposal we had included a first phase base on biomass energy," Gervais wrote by e-mail.

Without access to the levels of geothermal that were initially thought, Gervais said financial estimates changed and there was a requirement for a larger source of biomass than was available at the time.

"That additional risk required a complex web of guarantees and supply contracts between the city, federal government, Corix and potential customers," he wrote.

"The added complexity, change of energy source and the loss of momentum caused partners to gradually lose interest in the project." Communication with Corix slowed down, Gervais said, eventually ceasing completely, although he noted there wasn't a specific event that ended the partnership.

Van Tighem added that, "The requirement to spend a certain amount of the grant funding very early in the project raised the investment risk beyond what most private investors would be willing to undertake and that was that - the risk was too high based on timing."

With 60 per cent of all energy costs in Yellowknife associated with heating, Gervais said there are still huge opportunities for anyone looking to establish an alternative supply.

Even with the low grade heat, both Heyck and Van Tighem said there could potentially be an application for geothermal in the future, for example in keeping city water at an above-zero temperature during winter months.

"I think one of the things we learned was that we may need to establish our experience with these things on a smaller scale," said Heyck.

"One of the things our Community Energy Plan has been looking at is the notion of district energy as perfectly viable, on the scale that is manageable to start with and ensuring we have proven technologies in terms of the fuel source."