As the Supreme Court said in its ruling two years ago, it's not a tax; it's a pricing mechanism. It doesn't go back into general revenue of the government. It's revenue neutral, and all of the money collected goes back—
Evidence of meeting #100 for Environment and Sustainable Development in the 44th Parliament, 1st session. (The original version is on Parliament’s site, as are the minutes.) The winning word was change.
A recording is available from Parliament.