A major overhaul of Steam Unit No. 2 (ST2), a generating unit at the Apache Generating Station in Cochise, Arizona, has reached completion just in time to meet the peak summer demand.
The Apache Generating Station was established in 1963 by Arizona Electric Power Cooperative (AEPCO) to fulfill its mission to provide reliable, affordable power to rural communities across Arizona. It is still in operation today and remains a cornerstone in AEPCO’s portfolio due to the diligent maintenance and care provided by the AEPCO team.
The major overhaul of ST2 showcases the careful planning and long-term thinking needed to keep costs low without sacrificing reliability or performance. The overhaul of ST2, which took approximately 12 weeks to complete, exemplifies AEPCO’s dedication to maintaining optimal performance levels for all legacy generating units.
The focus of the overhaul was to address any operational or mechanical deficiencies in the turbine, boiler, and pollution control equipment, ensuring that ST2 can operate at its full load capacity without any obstacles.
While ST2 is designated as a base load unit, it is now also utilized as a peaking resource to support fluctuations in demand. Mike Nelson, the executive director of power production for AEPCO, confidently stated that, upon completion, the unit will be restored to full generation capacity and should be able to meet members’ needs for years to come.
Now that the overhaul is complete, ST2 will be capable of producing 195 gross megawatts of energy to support the needs of AEPCO’s members. AEPCO’s diligent maintenance strategy is built on a proactive approach, with major overhauls of generating units typically completed on a six-year cycle. The planning process for these overhauls typically commences two years in advance, ensuring meticulous attention to detail. According to Mike, the project timeline “takes into consideration the wear cycle of components that should not fail on a routine basis.”
Planning major overhauls based on the lifespan of key components guarantees optimal performance of the unit and minimizes the risk of unexpected downtime and disruptions in power generation. These planned major overhauls play a crucial role in allowing maintenance and repairs to be carried out on generating units, addressing issues that cannot be rectified while the turbine is in operation. They also extend the lifespan of the generating turbines, allowing AEPCO to avoid unnecessary costs for members by utilizing its existing resources to their full potential.
Thanks to a seasoned team of AEPCO staff and contractors, the overhaul has been completed just before summer demand peaks, with no significant incidents to report. AEPCO remains dedicated to its mission by prioritizing preventive maintenance and carefully planned overhauls.
By investing in infrastructure upkeep and staying ahead of potential challenges, AEPCO ensures it can continue meeting the energy needs of its members for years to come.
The recent completion of the major overhaul of ST2 highlights AEPCO’s commitment to operational excellence, guaranteeing a stable and resilient energy future for its members and the rural communities they serve.
