Arizona Public Service and Tucson Electric Power expect to add about 16 GW and 4 GW, respectively, of renewable energy, energy storage and other resources over the next 15 years, according to integrated resource plans filed Wednesday with the Arizona Corporation Commission.
Under its resource planning roadmap, APS expects to add more than 6,000 MW of solar and wind power, coupled with about 2,000 MW of battery storage, by 2027.
APS evaluated exiting the coal-fired Four Corners power plant early, but said the least expensive option was to wait until 2031.
“We cannot responsibly support the early exit from Four Corners due to reliability concerns associated with the transition to newer, nascent technologies, as well as the lack of sufficient excess capacity resources in the Western United States and sufficient electricity transmission infrastructure needed to deliver replacement resource capacity to APS’s service territory,” APS said.
APS’s plan calls for adding hydrogen-capable natural gas combustion turbines. “Quick-start, hydrogen-capable, natural gas resources provide flexibility and could potentially be sited where existing coal generation is located,” the Phoenix-based utility said.
APS also expects to invest in energy efficiency, demand response and microgrids, according to the plan.
APS plans to issue “frequent” all-source solicitations to meet its needs, such as its 2023 request for proposals, which seeks at least 1,000 MW, including 700 MW of renewables as well as transmission options, according to its resource plan.
High-voltage transmission will be needed to access out-of-state wind resources that provide overnight energy and “greatly improves portfolio economics,” APS said. “Wind resources — particularly high capacity factor resources such as those located in New Mexico and other Rocky Mountain states — offer significant value to customers due to their relatively low cost and the output diversity they provide.”
APS expects its peak demand and energy needs will grow by 2.4% and 3.7% a year, respectively, driven by data center growth, large industrial customer growth and electric vehicle adoption.
TEP’s plan, which could evolve, calls for adding 2,240 MW of wind and solar power, 1,330 MW of energy storage and 400 MW of gas-fired generation.
“Efficient, flexible and lower-carbon natural gas-fired resources help create a bridge to a cleaner energy future,” TEP said. “Without it, our reliability could be undermined by a growing lack of dispatchable resources in the Desert Southwest.”
TEP plans to fully exit its roughly 900 MW of coal-fired generation by 2032, according to its resource plan.
TEP expects its peak load will grow by about 1.2% a year to 2,800 MW in 2038.