By: Korie Marshall
The next step in looking for the best place to drill to create electricity with geothermal heat near Valemount – magnetotelluric studies of the Canoe Reach.
Martyn Unsworth, Professor of Geophysics, and some grad students from the University of Alberta have been in the Valemount area this week, doing magnetotelluric (MT) studies of this end of the Kinbasket Reservoir for Borealis Geopower. Borealis has geothermal exploration permits for the area, and plans for a 15-20 megawatt power plant that could look like a small museum for modern art, like the HÔºsavÔk Geothermal Power Plant in Iceland.
Craig Dunn, chief geologist for Borealis, stopped by Valemount Secondary to talk about the project to the Grade 9 science class. The students knew that hydro is the biggest source of electricity in BC, but didn’t realize that coal is the biggest source in Alberta. Their guess was oil. And they agreed with Dunn that it is embarrassing that Canada is the only country on the Pacific Rim that is not creating electricity with geothermal.
The kids know that the power goes out here in Valemount about five or six times a year, if not more, but that it rarely goes out in Vancouver. Dunn explained that’s because of the single long transmission line, and because we’re at the end of it. Not only could a power plant here power the village, it could be fed back into that line for other people to use.
Dunn explained how the MT studies worked, and showed the students some of the other tools he and other researchers from Borealis have been using to look for the best spot to drill – like a hand held temperature probe, a CO2 sensor, a paint scraper to collect some bark samples, a garden trowel to collect soil samples. All of this non-invasive stuff helps them collect data, and using iPads in the field, they enter and track the information far more efficiently than they could have in the past. Using science, it all gives them a picture – a map of the fault system beneath us, without drilling. And that helps them find the best place to drill, which is the biggest expense – and most risk – in building a geothermal power station.
The students had some great questions. Like are there problems with drilling this deep? Dunn says they drill very deep all the time in the oil industry, but there has been a risk of “microseismicity” – minor earth quakes caused by the drilling – and people are doing studies now to test if the microseismicity was happening before the drilling.
“Can you lose the heat, maybe if 40 or 50 years, if the plates are moving?” one student asked. Dunn explained the heat has been under us here in Valemount for tens of thousands of years, and the plates move about the same rate as your fingernails grow, so once you start generating electricity and feeding the water you pull up back down to reheat, it is pretty much self-sustaining.
“Will you need to build one of those great big power lines to get the power to town?” asked another student. Dunn says they might be able to use a distribution line, the much smaller kind that runs along streets, and there is already some of that infrastructure on the east side of the reservoir.
“How much will it cost?” Dunn says $75 to $80 million, which sounded like a lot to the kids, but to put it into perspective, some heavy oil projects cost $3.5 billion. And who would pay for it? Dunn says partners who invest, because they will be able to sell the power they generate to BC Hydro.
“But is it bad for the environment?” Dunn says the closed-loop system – water in one loop, going back into the ground heats another liquid in another closed loop which turns a turbine – means there are no emissions, and no by-products except heat. And in Canada, it is ridiculous to think of heat as a waste product, so maybe someone can build something close to the power plant that can use the heat – like some green houses or a year-round skateboard park.
While Dunn is talking to the secondary school students, Unsworth and his own students are still down the Canoe Reach, moving the MT equipment to get more readings. The equipment is basically three metal poles attached to a computer system, and powered by a car battery. The poles are buried in the ground, one east-west, one north-south and one vertical and left for a few hours or overnight to collect data. Each unit is worth about $85,000, so someone has to camp out if they leave the system in place, to make sure no one disturbs it.
The testing is expensive and time consuming, but Unsworth says it can measure as deep as between 50 and 100 kilometers if left in place for 2-3 days. Borealis is not looking that deep – only between two and 10 kilometers, and they are looking at a transect of the Canoe Reach at about the 10 km mark on the East Canoe FSR. That is closer to town than the hot springs – the hottest in Canada, says Dunn, which have been mostly buried under water since the flooding of the reservoir in 1973 – but from previous studies, that is where Borealis has decided their best chances are. They have picked five or six points in a relatively straight line across the valley, which meant pulling a small boat with equipment across the Canoe River (and possibly a cold swim for someone). Unsworth said he had thought they might be able to wade across the Canoe River but clearly that is was not an option.
Unsworth says they used to have to wait to get back to the office to start looking at the readings, but with faster computer these days, and because he’s looked at readings for about 30 years now, he can start to get an idea what he’s looking at while he is in the field. By measuring the electromagnetic readings from the material underground and doing some “tortuous mathematics”, Unsworth says you can measure the electrical resistivity of the earth at various depths, which gives you a model of where the faults are. He might even be able to pinpoint the Rocky Mountain Trench.
“He better be able to,” says Dunn with a grin.
