UniSource Energy Services is pursuing a balanced plan to maintain affordable, reliable energy for our communities, supported by proactive, transparent communications with our customers and regulators.
That’s why UniSource, known legally as UNS Electric, Inc., is considering adding four natural gas-fired turbines capable of generating around 50 megawatts (MW) each to a pair of similar turbines at our Black Mountain Generating Station in a remote area of Mohave County. Though our plans remain preliminary, we have communicated about them openly with local leaders and other area stakeholders.
Although a recent op-ed claimed these proposed additions were not part of our latest 15-year Integrated Resource Plan (IRP), our need for 200 MW of new gas turbine capacity was in fact mentioned repeatedly, including on page 2 in a letter from our president and CEO. New turbines would complement our planned additions of renewable resources and energy storage, supporting reliability and growth. They also would reduce our exposure to volatile prices and increasing capacity constraints on the western grid, as we currently rely on other regional providers for about half the energy we deliver to customers.
That same op-ed criticized our request that the Arizona Power Plant and Line Siting Committee determine whether a Certificate of Environmental Compatibility (CEC), issued by that group and approved by the Arizona Corporation Commission (ACC), is needed to authorize the site for such a project. The relevant statute (A.R.S. 40-360) seems to say it isn’t necessary, as generating units subject to that requirement are defined as having “a nameplate rating of one hundred megawatts or more.” The nameplate rating of each unit would be around 50 MW certainly less than 100 and they would be operated separately to meet customers’ fluctuating needs.
Had we sought to avoid public debate or escape the notice of regulators, as the op-ed alleged, we would not have asked our regulators to confirm in a public process that our understanding of the law is correct. Our public request is consistent with our early efforts to publicize the potential project itself, which have included public notices in newspapers, social media ads and detailed information on our website. It also does not compromise our commitment to environmental stewardship and transparent operations. The project will remain subject to thorough reviews and public outreach required for an updated air quality permit and a CEC for the short transmission line needed to connect it to the grid.
Greater clarity about the CEC requirement could help us respond to customers’ evolving energy needs more promptly and at a lower cost. We need to support projected increases in electric use across the region, driven by both extreme summer heat and economic growth. Our customers’ peak energy demands increased by 16% from 2015 through 2021 and we’re expecting demand will continue to climb over the next five years. There’s no question we’ll need more generating resources sooner rather than later to serve these needs. New growth won’t wait, and new facilities take significant time to build.
Although the op-ed suggested otherwise, our filed request makes clear that we plan to weigh the proposed addition of new natural gas turbines at Black Mountain Generating Station against other options, such as solar plus storage. We’ll conduct an all-source request for proposals that allows us to compare the reliability, performance, cost and other characteristics of this project with others submitted for consideration. Whatever project emerges from that process will remain subject to ACC review and approval before its costs could be recovered through customers’ rates.
Given the abundance of public engagement and review that will occur if we decide to proceed, a request that could result in a more efficient, less costly development process seems well warranted in the face of our customers’ need for new energy resources.As UniSource fulfills its obligation to serve those needs safely and reliably, we plan to keep affordability, transparency and efficiency front and center. To learn more about the process and to track our progress, please visit
https://www.uesaz.com/black-mountain .
Erik Bakken is senior vice president, energy resources and chief sustainability officer for UNS Electric, Tucson Electric Power and their parent company, UNS Energy.
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