There's the idea that if you get a carbon price, it sends the risk signal to all industry, and then they can decide how best to attack it. If government comes up with an idea and they've quantified the cost of carbon to Canada and Canadian taxpayers, Canadian ratepayers, they can apply that price to industry. Then industry can go on their own and best figure out how to deal with it.
The carbon price has the luxury of being the most transparent to everyone, in that it clearly tells everyone what we think the cost of carbon is to this country, and then business can deal with it however they want.