The big question is how much of that heat can be economically tapped?
As a general rule, the hotter and shallower the resource the more economical it is to exploit based on current technologies. The higher the temperature the easier it is to extract the volume of heat required to spin a turbine and generate electricity.
But there aren’t many places in Canada, beyond northern B.C., Alberta and the Yukon, that have that right combination of temperature and depth. Everywhere else, you’ll have to drill deep – as much as 10 kilometres down – to find enough heat. That’s a deal-breaker with respect to cost and risk.
It’s also a nut Ian Marnoch of Port Severn, Ont., is trying to crack. For the past seven years the Ontario inventor has been developing a new kind of “heat engine” that he says can generate electricity more economically from lower-grade heat. And that heat could come from anywhere: the ground, the sun, or an industrial waste process.
