Tuscon Energy’s 2020 IRP, filed to the Arizona Corporation Commission (ACC), outlines how the utility aspired to shift its generation mix cleaner energy sources. Key elements of the plan are the addition of 2,457 MW of new wind and solar power, of which 457 MW is due to become operational in 2021.
Capitalizing on falling cost of RES and gas generation
“Maintaining reliable service with higher levels of wind and solar power requires responsive, efficient natural gas resources as well as storage, which is projected to become much more affordable over the next decade,” said TEP chief executive David G. Hutchens.
“Our plan is designed to capitalize on those price reductions to achieve ambitious carbon emission reductions without compromising on cost-effectiveness or affordability.”
To balance intermittent renewable energy supply, TEP also plans to add 1,400 MW of new energy storage systems. The utility stressed “energy storage systems are projected to cost significantly less after 2030 than they do today.”
Taking steps to exit coal generation by 2032
The proposed coal exit, foresees to ramp down and ultimately retire TEP’s two coal power units at the Springerville Generating Station in 2027 and 2032. That timeline would allow TEP to reduce the plant’s workforce through attrition rather than layoffs.
Beginning in 2023, TEP plans to transition to seasonal operations that idle one of the Springerville power units during cooler months. Both units are still needed to meet summer peak demand. After the closure of Unit 1 in 2027, TEP plans to continue seasonal operations of Unit 2 through 203
TEP is on track to retire more than 600 MW of coal generation by June 2022 through recent and scheduled closures at the Navajo and San Juan Generating Stations (SGS). But TEP currently still dispatches two coal-fired units at the Four Corners Generating Station that are due to close in 2031.
SGS Unit 1 can produce up to 387 MW and came online in 1985, while Unit 2 can produce 406 MW and came online in 1990. Two further units were completed in 2006 and 2009 but these are owned by Tri-State Generation and Transmission Association and Salt River Project, respectively.
Contributing a ‘fair share’ to global CO2 reduction efforts
If implemented, the TEP’s switch to gas and renewables would allow the utility maintaining a steady energy supply for customers in Southern Arizona while avoiding more than 50 million tons of CO2 emissions over the next 15 years.
The emission reduction target represents TEP’s “fair share of worldwide efforts” to limit global warming to well below 2 degrees Celsius under the 2015 Paris Agreement, it pointed out.
“Our goal is ambitious but realistic, reflecting what we can achieve using existing technology during the 15-year time period covered by our IRP,” said TEP chief executive David G. Hutchens.
“We’ll be reducing carbon emissions at a pace that places us at the forefront of global efforts to combat climate change.”