Three activists have tied themselves to a flatbed truck carrying a large caricature of Energy Minister George Smitherman with a caption reading, "Don't nuke green energy."
Spokesperson Shawn-Patrick Stensil says his group wants Smitherman to explain why he won't replace the Pickering nuclear station with green energy when the reactors reach the end of their lives in 2013.
Stensil says the minister talks a lot about green power but needs to take concrete action.
He adds if Smitherman is really interested in expanding green power, he can prove it by replacing the nuclear reactors.
Stensil, one of 14 activists taking part in the protest, says spending money on nuclear plants robs renewable energy of the financing it needs to grow in the province.
"You can't plan to spend tens of billions on nuclear reactors and call yourself green. That's green-washing," he said.