Among the advisers who helped put the agreement in place was Henry Henderson, the Sun Ra-quoting director of the Midwest Program of the Natural Resources Defense Council. Henderson, who previously served as an assistant Illinois attorney general and as Chicago’s environment commissioner, took a few minutes to explain to me why he thinks this is a big deal.

Best of Chicago voting is live now. Vote for your favorites »

We just passed our framework to the governors. It includes coal-based utilities, energy and gas interests, renewable energy groups, and NGOs like mine.

The last meeting of the advisory council, which was earlier this month in Minneapolis, was extraordinarily intense. On the final day, this agreement was worked out [after negotiations] with several coal utilities.

With this kind of a system you charge fees for transactions, creating a specific funding stream that can go into mitigating the problem. And finally, among the people who are most vociferous about this are people who hate taxes. So it’s a pragmatic political thing.