AzGT Operators Train in How to Handle Emergency Loss of Generation

Operators prepare to initiate “blackstart” recovery if generation or grid systems go down

Robert Cubley, AzGT senior system operator, discusses a simulated “blackstart” scenario with system operators Jason Herron (left) and Adan Garcia. “Blackstart” refers to the procedures that would be necessary to restore power if a cyber- or physical attack, extreme weather, or other form of infrastructure failure shuts down all generation to the grid.

BENSON – No utility ever wants to face the loss of its entire electrical system, but operators at Arizona G&T Cooperatives receive intensive training on how to recover from such an emergency.

“We practice a scenario where the entire grid has gone black,” said Robert Cubley, AzGT senior system operator. “There’s no generation on line; no one’s lights are on. It could be weather-related, it could be a physical or cyber-attack, it could be something outside our area. We prepare for the worst possible scenario.”

Over a recent six-week period, AzGT system operators broke into groups that spent three days a week in “blackstart” training. It’s called blackstart because restoring generation and power to the grid would start from nothing. The training, held annually, builds the skills and the confidence needed to restore power.

In case of a blackstart, operators would follow procedures to start up AzGT’s blackstart unit, Gas Turbine 1, at the cooperative’s Apache Generating Station near Cochise, Arizona. Once GT1 is online, operators would build a path to GT2 to increase generation capacity. They would then prep substations one by one, and send power needed to start up Apache Station’s two major steam-powered generating units, ST2 and ST3.

Communication would be essential to restoring power—communication between operators at Apache Station, the control room at AzGT headquarters in Benson, and the AzGT transmission system.  Communication with AzGT’s Member distribution cooperatives would also be critical. AzGT provides wholesale power to six Members throughout Arizona and parts of California and New Mexico—and these distribution co-ops serve 141,000 consumer-members, or approximately 420,000 people, at the end of the line.

If the emergency occurred during the hot summer months, “It would probably be a couple of days before we’re up and running and restored fully,” Cubley said.  “We don’t want it to happen, but if it does, we’re confident that we could handle it.”


About Arizona G&T Cooperatives
Arizona Electric Power Cooperative (AEPCO) and Sierra Southwest (Sierra) together comprise Arizona G&T Cooperatives ( AEPCO owns and operates the 625-megawatt (combined gross) Apache Generating Station, located at Cochise, east of Benson. AEPCO also owns, operates and maintains 866 miles of electric power transmission line—including line owned in part with other utilities—and 36 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 AzGT Member cooperatives and customers, and helps maximize solar and other renewable tax credits. Sierra has initiated two utility-scale solar projects. AEPCO’s 20 MW Apache Solar project is located on AEPCO property adjacent to and northeast of Apache Generating Station. The second project includes SunAnza Phase I, a 2 MW solar array, as well as SunAnza Phase II, which includes an additional 1.4 MW solar array and a battery storage system, all on property owned by Anza Electric Cooperative adjacent to its 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 a California member, Anza Electric Cooperative, Anza.

These Member cooperatives own AzGT and, by extension, AzGT’s Member distribution cooperatives are owned by their members—the people at the end of the line who use the power.

AEPCO also serves five Class D energy services Members which are scheduling and trading customers and which include the Central Arizona Water Conservation District, Phoenix, AZ; Lincoln County Power District #1, Pioche, NV; Metropolitan Water District of Southern California, Los Angeles, CA; Southwest Public Power Agency, Maricopa, AZ; and Valley Electric Association, Pahrump, NV.

AEPCO is also a Member/owner of ACES, a nationwide energy management company ( that helps its Members and customers buy, sell, and manage energy more efficiently and with less risk. The AEPCO/AzGT Benson campus hosts the ACES West Regional Trading Center (WRTC), which benefits AEPCO/AzGT Members and customers.