A new project that involves drilling a hole near the Takhini Hot Springs just a few centimetres across but 500 metres deep will soon be giving researchers a better idea of the Whitehorse area’s potential to generate power via geothermal energy.
A partnership between the Ta’an Kwäch’än Council, Da Daghay Development Corporation and Yukon Geological Survey, the project is funded through the territorial and federal governments. It will see crews drilling into the earth about three kilometres west from the hot springs, on Ta’an Kwäch’än land, and then inserting a thermistor string — essentially, a cable with multiple thermometers in it — down into the well to measure the ground temperature at various depths.
If temperatures register at 90 degrees celsius or above, that would mean there’s good potential for establishing a geothermal power plant, using the heat from earth to create steam and passing it through a turbine to generate electricity, said Maurice Colpron, head of bedrock geology with the Yukon Geological Survey.
“The grand prize in geothermal energy would be power generation,” Colpron said in an interview Nov. 14, noting that the Takhini Hot Springs were a clear indicator to researchers that there was some sort of geothermal energy present in the area.
The project is already starting to pay off though, said Da Daghay Development Corporation CEO Ben Asquith — all the contracts for work on the project were awarded to local businesses.
“We’re proud to be sourcing everything locally, we’re proud to be partnering with the Yukon government and we’re really excited to see the results, to see what we can look at in terms of business case,” he said.
However, there’s still a lot of work ahead before a power plant even becomes a consideration.
For starters, crews are still in the process of boring the hole, work which began Oct. 30. After starting off with a reverse circulation drill, crews recently switched to a diamond-tipped one after passing the 50-metre mark, with the well’s diameter, which started off at about 15 centimetres, shrinking to about eight centimetres now.
The project’s goal right now is to get the well to a depth of 500 metres and, failing that, to get at least a minimum depth of 300 metres in order to mitigate the impact of weather and other atmospheric effects on the temperature readings, Colpron said. The endeavour, which will see crews working around the clock, is expected to take up the better part of three weeks.
“We are trying to make sure that we have a vertical hole so that we’re going straight down 500 metres as opposed to deviating … so it requires kind of going a little slower,” Colpron explained, adding that the crew must also be cautious of hitting pockets of pressurized water or natural gas. The hard rock the crew is encountering is also making progress slow. But in the long term that’s a good thing, Colpron said, because it means the well will be stable and less likely to collapse in on itself.
Once the well is completed and crews have inserted the thermistor string, the hole will be grouted to ensure the thermometers are in contact with the surrounding rock and then permanently capped off, Colpron said, after which more waiting begins.
“We expect it’s probably going to take at least six months before we start reading temperatures that are not affected by the drilling itself. As we drill, we are obviously heating the rocks around the hole so we need that temperature re-equilibrate,” he said, adding that someone will be going to the site about once a month to download the data from the wellhead.
“The current plan is basically, once we’ve repeated consistent temperature (readings) for, let’s say, for three months in a row, then we’ll determine, ‘Okay, this is the real temperature, there’s no fluctuations anymore,’ and that’s really, at this stage of our study, that’s the goal, just to get an accurate temperature measurement in the Whitehorse area.”
If temperatures are recorded in the 90 to 100 C sweet spot, Colpron said that would only be the beginning of exploring geothermal energy production. From there, researchers would need to drill more — and deeper — holes to determine how viable the resource is, and also check for underground caverns containing water that could be turned into steam.
But even if the temperatures don’t hit the energy production range, the project isn’t all for naught — if crews discovered pockets of water at, say, 50 C, that could still be used to heat buildings, and the geothermal data generated will be unlike anything that’s ever been collected in the Yukon.
“Right now, the only, the best data that we have for the crust temperature in the north, in the Yukon in particular, it comes from a few deeper oil and gas exploration wells, so that would be around Eagle Plains or Kotaneelee Field,” he said.
“Our experiments are going to be the first ones that are specifically designed for that purpose, so, yes, whatever we find, this is going to be a new piece of data that will make us understand, better, the thermal regime of the crust in the Yukon.”
Colpron added that there are plans to drill one or two more test wells around southern Yukon to collect the same kind of data, although the locations have not been finalized yet.
Contact Jackie Hong at firstname.lastname@example.org