The past month across the western U.S. has been filled with victories against coal:

And today, we saw some big news out of Colorado. The Colorado Public Utilities Commission (PUC) approved the retirement of 902 megawatts of coal power. They are retiring all of the Denver metro area’s coal plants by no later than 2017. (On Tuesday, they’d decided to retire all but one of the Denver plants, but today they decided on the final one — the 352 megawatt “Cherokee 4 unit.”)

The Sierra Club has been heavily involved in this Colorado battle against coal (and all of the above victories). Last April, the Sierra Club and a strong coalition of environmental groups helped pass legislation — the Clean Air Clean Jobs Act — which requires action from Xcel Energy on its coal fleet and clean energy.

“All summer and fall, we and our coalition allies have been advocating before Colorado’s Public Utilities Commission and organizing Colorado’s public health and clean energy voices to speak loudly and often in support of retirement of as much of Xcel’s coal fleet as possible,” said Alex Levinson of the Sierra Club.

“Our aim has been to provide critical public support for PUC Commissioners and Xcel Energy to do the right thing … (and provide) critical expert support demonstrating the economic wisdom for Colorado ratepayers of a move away from coal — with all its regulatory uncertainty and rate volatility.”

These western U.S. victories show a continued move away from coal and toward clean energy. At this rate, we will have locked down the retirement of 10 percent of the coal fleet in the West (a total of 33,000 megawatts) in early 2011.

Coal is coming down, which in turn opens up the market place, and clean energy is stepping in. The path forward is clear, the West is headed towards clean energy.