The carbon dioxide emissions from Ontario coal stations would be more costly to remove but are not something we should be concerned about since their contribution to global climate change is insignificant.
I suppose you could argue that Canada's contribution to global CO2 is an "insignificant" two per cent (a contribution we make even though we have just 0.005 per cent of the world's population). You also could argue that Ontario's coal-fired electrical plants generate an "insignificant" 40 per cent of that province's CO2 emissions from industrial sources.  In fact  , coal has the highest greenhouse gas (GHG) emissions intensity of all combustible fuels, and four of Canada’s five largest single emitters are coal-fired electrical generating stations.
Perhaps, though, Harris is trying to say that CO2 is an "insignificant" contributor to climate change in general, a fiction that he probably learned from his brother-in-disinformative-public-relations, Dr. Tim Ball (see next post).
There is an argument to be made that Ontario Premier Dalton McGuinty could have taken another tack. Perhaps he could have insisted (like B.C. Premier Gordon Campbell) that coal-fired plants find a way to sequester their CO2 output.
But the real issue here should be this: who's paying Tom Harris to lobby on behalf of the Ontario energy industry? And why should we allow the High Park Group  to evade its reporting requirements under the federal lobbyist's registry by pretending that the Natural Resources Stewardship Project  is an independent operation?