Alternative Plan Achieves Better Visibility Improvement Than EPA Sought at Much Lower Cost

Benson/Cochise, AZ – The U.S. Environmental Protection agency has announced its approval for an Arizona Electric Power Cooperative alternative plan that will significantly reduce power plant sulfur dioxide and particulate matter emissions at the Apache Generating Station east of Benson that  contribute to regional haze.

The AEPCO alternative plan submitted last year calls for converting one of the units to natural gas and installing upgraded emissions controls on both units, resulting in overall emissions reductions similar to  the EPA’s original Federal Implementation Plan, but  at a much lower cost of approximately $32 million.

“The original rule from the EPA would have required us to spend $200 million or more on Selective Catalytic Reduction (SCR) technology that would not have achieved the result we were seeking. This is a much better solution and we’re happy the EPA saw the merits of our alternative proposal,” said Michelle Freeark, director of safety and environmental services.

Freeark has called the AzGT revised plan a ‘win-win’ for all involved.

“It achieves the common goal we share with the EPA to improve visibility in the great national parks and wilderness areas around our plant for present and future generations, and it also shows how a generation and transmission cooperative can work closely with a regulatory agency to achieve a solution that works for both,” Freeark said.

Patrick Ledger, AzGT CEO, said the alternative plan is the result of extensive work and planning and is “great news for the people at the end of the line who use our power.”

“We have a responsibility to our distribution cooperatives and the rural people at the end of the line who rely on us to provide safe, reliable and affordable electric power and we have a great team that kept that in mind as we worked to develop our alternative to the EPA’s plan,” Ledger said.

It took intervention by members of Arizona’s Congressional delegation to arrange discussions between the EPA and AzGT officials that resulted in proposed acceptance of the AzGT plan.  .

The Arizona Department of Environmental Quality (ADEQ) opened a public comment period on the plan from February 19 – March 21, 2014.  A public hearing by ADEQ was held March 26, and the agency then forwarded the revised plan to the EPA for its review.  It was after that public comment and public hearing process and its own review that the EPA proposed to approve the AzGT alternative on Sept. 8, 2014, followed by another public comment period that ended Nov. 10, 2014. The plan then went to top level EPA officials for final review and approval.


Arizona’s G&T Cooperatives

Arizona Electric Power Cooperative (AEPCO), Southwest Transmission Cooperative (SWTC) and Sierra Southwest Cooperative Services collectively make up Arizona’s G&T (generation and transmission) Cooperatives.

AEPCO owns and operates the 605 (combined gross) megawatt Apache Generating Station at Cochise, Arizona, east of Benson.

SWTC owns and maintains more than 620 miles of transmission lines and 27 substations that transmit wholesale power from the Apache Generating Station to six Member Distribution Cooperatives in southern Arizona, northwestern Arizona in Bullhead City and Mohave County, and Anza in California.

Combined, the Distribution Cooperatives that receive AEPCO’s wholesale power serve more than 147,000 meters representing more than 350,000 individual residential, commercial, agricultural and industrial customers.

The six Class A Member Cooperatives that receive wholesale power from AEPCO include five in Arizona; Duncan Valley Electric Cooperative in Duncan, Graham County Electric Cooperative in Pima, Mohave Electric Cooperative in Bullhead City, Sulphur Springs Valley Electric Cooperative in Willcox, Trico Electric Cooperative in Marana, and the California member, Anza Electric Cooperative in Anza.  These Member Cooperatives own the AzGT Cooperatives and by extension, the G&T Cooperatives are owned by their Members, the people at the end of the line who use the power.

The cooperatives are also Rural Utilities Service (RUS), a federal agency, borrowers.

The G&Ts and its Member Cooperatives are not-for-profit utilities.



  • In November 2012 the EPA issued a final rule for Best Available Retrofit Technology (BART) to control emissions the agency said contributed to ‘regional haze.’ The rule would have required installation of expensive Selective Catalytic Reduction technology on both coal units at Apache at a cost of $200 million plus, which was unaffordable.
  • 2012 – Jan. 2013, Congressional intervention encouraged the EPA to reconsider its final ruling, sit down and discuss with AEPCO whether  less costly alternatives could achieve visibility goals.
  • 15, 2013: We provide EPA with our alternative plan, which we call Better than BART. Estimated cost: $32 million.
  • 19-March 21, 2014: The Arizona Department of Environmental Quality (ADEQ) takes public comments on the alternative plan.
  • March 26, 2014: ADEQ holds a public hearing in Benson as part of a review process.
  • April 2014: ADEQ officials forward the revised State Implementation Plan incorporating our alternative to the EPA, recommending approval.
  • June 7, 2014: The EPA announces it will review its final rule.
  • 8, 2014: The EPA issues a formal “proposal to approve” the AzGT alternative.
  • 10, 2014: After the final public comment period on the EPA’s proposal to approve ends, the EPA begins its final review of our plan.
  • February 2015: EPA gives final approval to our plan.
  • 5, 2017: Compliance deadline.


  • Convert one coal unit to natural gas
  • Install selective non-catalytic reduction (SNCR) on remaining coal unit
  • Upgrade Scrubbers on remaining coal unit
  • Install/upgrade Low NOx burners on both units
  • Greater Reductions SO2 and Particulates (than EPA required)
  • Capital Expense: $30 – $32 Million (down from $192 million)

We are the first Arizona utility to settle out of court with the EPA on regional haze. Our solution achieves the common goal that we share with the EPA to improve visibility in national parks and wilderness areas. It also shows how a generation and transmission cooperative can work closely with regulatory agencies to achieve a solution that ultimately benefits the public, our members, and ratepayers at the end of the line. Other utilities are going down the same path – and asking us for advice on how to get through the process.