EPA Issues Final Affordable Clean Energy (ACE) Rule

ACE rule replaces proposed Obama-era Clean Power Plan with one that Provides flexibility as utilities continue to lower carbon emissions

EPA logoJune 19 2019 — For Immediate Release


BENSON – The U.S. Environmental Protection Agency (EPA) today released the final Affordable Clean Energy (ACE) rule, replacing the Obama administration-era Clean Power Plan (CPP) as the primary regulatory mechanism for seeking reductions of carbon dioxide emissions from existing coal-fired power plants.

“We expect the ACE rule will provide greater certainty and the flexibility that’s needed to help the nation’s utilities as they continue to make progress in reducing carbon emissions,” said Michelle Freeark, executive director of regulatory affairs and corporate services for Arizona Electric Power Cooperative (AEPCO).

The ACE rule replaces the CPP’s mandated across-the-board carbon dioxide emissions reductions with a requirement that allows power plants with electric generating units that are affected by the rule to use applicable technologies and good maintenance and operating practices to improve efficiency and reduce carbon dioxide generation per megawatt/hour (MWh) of electricity generated.

“This approach provides a path forward for member-owned electric cooperatives like AEPCO to continue to provide safe, reliable, and affordable power to rural communities,” Freeark said.

Freeark said the “one size fits all” reductions required by the original CPP “would likely have required the retirement of substantial coal-fired generating capacity, straining the ability of the integrated electric power grid to provide adequate supplies during peak demand periods, such as during our hot Arizona summers.”

In place of the extreme CPP-mandated reductions, ACE requires coal-fired units to produce energy as efficiently as is reasonably possible using certain technologies and practices that have been thoroughly vetted and are known to be effective.

“This approach will continue the significant progress that the utility sector, including cooperatives, has already achieved toward carbon dioxide emissions reduction and does so without causing excessive immediate retirement of units needed for peak demand periods,” Freeark said.

“AEPCO looks forward to working with the Arizona Department of Environmental Quality and other Arizona utilities in implementing the ACE rule and in continuing progress toward carbon dioxide emissions reductions that benefit our environment while avoiding excessive burdens on AEPCO’s members,” said Freeark.

Three FAQs about the ACE Rule:

  • The ACE rule establishes emission guidelines for states to use when developing plans to limit carbon dioxide (CO2) emissions at coal-fired power plants within that state.
  • ACE identifies heat rate improvements – improvements in efficiency – as the “best system of emission reduction” for CO2.
  • These improvements can be made at individual facilities without a “one size fits all” approach

About Arizona G&T Cooperatives

Arizona Electric Power Cooperative (AEPCO) and Sierra Southwest (Sierra) together comprise the Arizona G&T Cooperatives (www.azgt.coop). AEPCO owns and operates the 605-megawatt (combined gross) Apache Generating Station, located at Cochise, east of Benson. AEPCO also owns, operates and maintains 829 miles of electric power transmission line—including line owned in part with other utilities— and 27 substations to provide wholesale electric power from Apache to six member distribution cooperatives in southern Arizona, western New Mexico, northwestern Arizona and California.

Sierra is the vehicle to develop new ways to serve the renewable energy needs of our Member cooperatives and customers, and helps maximize solar and other renewable tax credits that are available. Sierra has initiated two utility scale solar projects; the 20 MW Apache Solar project on AEPCO property adjacent to and northeast of AGS, and SunAnza, the 2 MW solar array adjacent to the Anza EC headquarters in Anza, California.

Combined, the distribution cooperatives that receive AEPCO’s wholesale power serve more than 161,000 meters representing more than 420,000 individual residential, commercial, agricultural, and industrial member/consumers.

The Class A member cooperatives that receive wholesale power from AEPCO include Duncan Valley Electric Cooperative, Duncan; Graham County Electric Cooperative, Pima; Mohave Electric Cooperative, Bullhead City; Sulphur Springs Valley Electric Cooperative, Willcox; Trico Electric Cooperative, Marana; and our California member, Anza Electric Cooperative, Anza, California.

These member cooperatives own the AzGT and, by extension, the G&T Cooperatives are owned by their members—the people at the end of the line who use the power.