There are a few growers in B.C. who do supplemental lighting. There's a grower or two in Quebec, as well. Even then, they struggle with the economics of it.
There are ways to get around it, with things such as combined heat and power, where you can produce your own electricity on site and sell the rest to the grid. In Ontario, they're trying to develop programs that will work there as well.
It's trying to figure out a number of different ways to make it, whether it's producing your own electricity, or off-peak electricity pricing, or different technologies that will allow you to reduce your cost to do that 12-month production.