For more than three years, the U.S. Environmental Protection Agency has been considering requiring new emission controls to reduce haze-forming nitrogen oxides (NOx) released as a byproduct of burning coal to create electricity at the Navajo Generating Station. The Central Arizona Project followed these proceedings closely because the generating station provides more than 90 percent of the power CAP uses to deliver Colorado River water to Central and Southern Arizona.

EPA has now published its proposed rule. The rule, if finalized, would set a new standard for NOx emissions of 0.055 pounds/million BTUs. The only currently available technology that can meet that standard is Selective Catalytic Reduction (SCR). The installation of catalytic reduction at the generating station will cost at least $500 million. This cost could exceed $1.1 billion if additional air filters are also required at the plant to remove the airborne particulates created by the SCR process.

EPA's proposed rule is disappointing given a 2012 National Renewable Energy Laboratory (U. S. Department of Energy) study which found no conclusive evidence that these expensive NOx controls would yield any perceptible improvement in visibility at the Grand Canyon and other areas of concern.

However, recognizing that the Navajo Generating Station owners have already voluntarily installed a $45 million NOx control system, the proposed EPA rule provides an extended time-frame to meet this new standard, moving the deadline from 2018 to 2023. EPA also leaves the door open to extending the deadline even further should additional reductions in NOx be proposed by the plant owners and operator.

While this may delay the onset of increased electricity costs, those higher costs will ultimately increase the cost of CAP water. CAP and the generating station owners must further evaluate the proposed rule and its implications before we can determine the exact cost of compliance.

Should the proposed rule be finalized, the specter of Navajo Generating Station closure still exists. A National Environmental Protection Act process must be completed and approved by the secretary of the interior. This is most probably a five-year or longer process. We remain hopeful that the environmental protection act process can be completed before significant financial investment must be made to comply with the proposed emission rule time frame.

Although the proposed rule will increase the cost of CAP water, knowing EPA's NOx emissions goal nevertheless provides a level of certainty to the Navajo Generating Station owners as they negotiate the coal, land and water agreements that allow the generating station to operate, all of which must be renewed before 2019. Other uncertainties must yet be faced, including future federal regulations addressing greenhouse gas emissions, ash disposal and other matters.

With publication of the proposed rule in the Federal Register on Feb. 5, the EPA has opened a 90-day comment period on the proposed emissions rule. CAP will continue to actively work with elected and appointed officials at all levels, agricultural and municipal entities, Native American tribes, Navajo Generating Station co-owners and our many customers to impress upon EPA the enormous impact that their emissions technology decision would have on the use of renewable Colorado River water in Arizona.

You can submit comments to the EPA before the ruling becomes final. To learn how, or for more information, please visit

Pamela Pickard is president of the Central Arizona Project board and David V. Modeer is its general manager.