The Navajo Generating Station, its owners, those who use energy produced there and environmental groups are proposing a way to reduce emissions at the station, which the Environmental Protection Agency is requiring, while still keeping the power generator open.

The EPA is seeking public comment on the plan, and if it is accepted, it could save water users throughout the state money, said David Modeer, general manager for the Central Arizona Project, a series of canals that deliver Colorado River water to many communities in Arizona, including Tucson.

The EPA issued rules in the 1990s aimed to reduce the emissions at a number of power plants in the country, with the goal of improved visibility at national parks.

The Navajo Generating Station, at Page, produces power for many power companies, and if the owners tried to comply with the EPA ruling, it likely would have been cost prohibitive, Modeer said, and force the plant to close by 2020.

"The cost is significant in order to reach compliance," he explained.

The plant's closure would drive up energy rates because the power is used to pump water throughout the state along the canals, Modeer said.

Tucson Water customers could see cost increases of 200 percent, he said, because the company depends on CAP water for 90 percent of its supply.

That's one reason environmental groups, tribes, the plant's owners, CAP and the U.S. Department of the Interior have offered an alternative plan: control emissions by shutting down one of three production units, which allows the plant to remain open.

"That lowers the emissions to keep us below the EPA standards until about the year 2030 before the year 2030," he said.

The projected energy need is expected to decline, so the reduction in energy production would not cause shortages, Modeer said. It also would keep rates down for those who pay for water, including residential customers.

"It certainly is going to keep water much more affordable than it would if we had to go out and find power sources that are different from the Navajo Generating Station," Modeer said.