The Environmental Protection Agency wants public comments on a new cleanup plan for a coal-fired plant that provides most of the electricity that pumps Tucson its drinking water.

The new plan would reduce total air pollution from the Navajo Generating Station over the next 30 years by more than two earlier EPA proposals — but at a slower pace.

It would delay installation of pollution controls at the Northern Arizona plant until 2030, nearly a decade later than under the earlier plans. At the same time, the new plan calls for a probable shutdown of one of the plant’s three generators by 2020 and of the entire plant by 2044.

The EPA will hold a public hearing Friday night in Tucson on the proposal. It was put together by a working group that included Central Arizona Project management, the Interior Department, the Salt River Project, two Indian tribes and some environmentalists.

But it has also split the environmental community. From an environmental standpoint, the basic issue is whether the new plan’s additional pollution curbs are worth the delays.

Economically, the delays are a plus for the power plant’s operators, which include Tucson Electric Power, CAP and Phoenix’s Salt River Project. The EPA’s proposed pollution controls will cost about $544 million to install, with costs topping $1 billion if additional controls are needed.

The power plant, one of the largest coal-fired plants in the country, lies on the Navajo Reservation near Page, close to the Utah border. It supplies more than 90 percent of the electricity that pumps CAP water uphill from the Colorado River to Phoenix and Tucson, and it provides hundreds of jobs. Tucson Electric Power owns a 7.5 percent share of the plant.

Its air pollution has been targeted for years by environmentalists and EPA officials who say the plant’s nitrogen-oxide emissions are hurting views at the Grand Canyon and other Southwestern national parks and damaging public health on the reservation.

The latest plan’s specifics:

— By 2030, the power plant would have to install pollution-control devices on all three of its generating units. That would reduce nitrogen-oxide emissions by more than 80 percent. Under two earlier plans proposed by EPA, the devices would have to be installed by 2018 or 2023.

— In 2020, the power plant would likely have to close one of its three generating units, triggering an immediate 33 percent emissions reduction.

— The closure would be averted if the Navajo Tribe, which currently holds no interest in the plant, were to buy an interest in it from the Los Angeles Department of Water and Power and the Nevada Power utilities. The two together own more than a 21 percent stake in the plant but have announced plans to sell their shares.

— If that unit remained open, all three units would have to reduce emissions by a total of 33 percent in 2020.

— By 2044, the Navajo plant would shut down, unless the tribe opts to run it itself.

— By that same year, this latest cleanup plan would have reduced emissions by 10 to 13 percent more over the period 2009-2044 than EPA’s original plans would have done. That’s because the shutdown of one generator by 2020 would reduce total emissions more than requiring all three power units to install pollution controls early on, the EPA says.

— The plan commits to reducing carbon dioxide emissions from the plant by 3 percent annually and to ensuring that by 2035, 80 percent of the U.S. Interior Department’s share of the plant’s power — the part that pumps CAP water to Tucson — comes from a clean energy source.

“This plan provides a road map to cleaner air, climate progress and a stronger clean energy economy,” said Vickie Patton, general counsel for the Environmental Defense Fund, one of two environmental groups that negotiated the latest clean-up plan.

“We had to work through some difficult issues but together we were able to develop an approach that provides for cleaner air at the Grand Canyon and surrounding communities,” Patton said.

But Sandy Bahr, of the Sierra Club, said the latest plan fails to meet federal Clean Air Act requirements for installing the best available retrofitting technology to clean power plant pollution by five years after a plan is approved. “What we’re saying is, ‘Stop polluting the Grand Canyon and other national parks and wilderness areas, and protect the health of people who have to breathe pollution from that plant,’” said Bahr, who chairs the Sierra Club’s Grand Canyon chapter.

For CAP, the latest cleanup plan offers a stable future for the power plant and spreads the cost of reducing emissions over a much longer period, CAP spokesman Mitch Basefsky said.

“Now, we will have a stable power source until we can find alternatives that will work, and it gives CAP the opportunity to approach the rate increases associated with the extra technology in a more deliberative manner,” Basefsky said.

But Bahr and Kevin Dahl of the National Parks and Conservation Association say they’re uncomfortable with the plan’s allowing the Navajo Nation to keep running the generating unit that otherwise would be closed in 2020. If all three generators are still operating, they’re skeptical that the 33 percent pollution cutback will still be enforced. “Who’s going to make sure they are doing that? There will still be a significant amount of pollution coming from the plant” if one unit doesn’t close, Bahr said.

But whether or not one Navajo generator shuts in 2020, the 33 percent reduction would “absolutely” be enforceable because it would be in the plant’s new operating permit, countered Kelly Barr, Salt River Project’s director of environmental management and compliance. All parties negotiating the new agreement agreed to reduce emissions by 33 percent either way, Barr said.

Contact reporter Tony Davis at or 806-7746.