In April, the Southwest Power Pool (SPP) expanded into the Western Interconnection, giving members access to crucial generating resources and planning services, along with support in keeping the lights on across the region.
SPP is also the country’s first regional transmission organization to span two interconnections, with an increased service area comprised of 25 utilities in seven states - Arizona, Colorado, Montana, Nebraska, New Mexico, Utah, and Wyoming.
“SPP’s western expansion is a landmark milestone for our organization, our new members and the broader energy industry,” SPP President and CEO Lanny Nickell said in an April 2 press release. “This is one of many bold steps we’re taking to deliver long-term value to more consumers.”
Operations began at midnight central time on April 1, following months of testing, simulation and coordination with participating utilities. Members including Colorado-based Tri-State Generation and Transmission Association said they expect the expanded SPP to deliver the same benefits already proven across the Central U.S., namely enhanced reliability, transparent grid governance, and lower wholesale costs through regional dispatch.
“Tri-State has been pursuing membership in a full, western regional transmission organization for more than a decade,” said the not-for-profit power supply cooperative in an email to Energy Daily. “Our core drivers are a reduction in seams, better environmental performance, improved generator interconnection, transmission system optimization, savings through more efficient dispatch, and a single consolidated transmission tariff.”
Though still in its nascent stages, the expansion may prove a “foundational move” for Tri-State and its neighboring transmission owners, officials said. Tri-State expects to garner $20 million in annual net benefits, a substantial return for its member cooperatives and public power entities in Colorado, Nebraska, New Mexico and Wyoming.
“Tri-State and its members constantly look for ways to lower costs and build long-term reliability,” said Duane Highley, CEO for Tri-State, in a press release. “For Tri-State members, our participation in the SPP RTO’s western expansion is about building a more efficient, resilient and affordable energy future – one that delivers real value today and positions our communities well for decades to come.”
A shared responsibility
With the expansion, SPP now manages a 732,000-square-mile footprint stretching across 17 states. Nine load-serving utilities lead an effort that Tri-State believes will, among other benefits, maximize transmission assets to handle surging energy demand. Unification of balancing authorities and transmission owner tariffs, meanwhile, will reduce “seams” created when energy transactions occur across multiple adjacent markets, Tri-State said.
“By operating a shared transmission system and competitive energy markets, RTOs help utilities work together instead of operating in isolation,” the utility said. “That cooperation leads to more efficient planning, more reliable service and lower overall costs.”
Tri-State’s member service territories cover nearly 200,000 square miles, including 39 cooperatives and power district customers. By anchoring itself to the Western Interconnection - one of North America’s two major alternating current grids – the utility must adhere to all reliability, planning and tariff standards set forth by the SPP.
As portions of Tri-State have been in an organized retail or wholesale market for more than a decade, transition into the SPP has been seamless so far, utility officials said.
“Our load in the Eastern Interconnect has been part of SPP RTO since 2015,” the utility said. “Our western grid load began participating in organized energy imbalance markets in February 2021, through the SPP Western Energy Imbalance Service and, several months later, in the CAISO Western Energy Imbalance Market. We have been 100% in some form of organized markets since 2023.”
Tri-State is now charting a course toward a zero-carbon energy future - a landmark the utility acknowledges it could never reach alone.
“We are a 100% compliant organization that will meet goals as required by state and federal statute,” said the utility. “Joining a regional transmission organization significantly increases Tri-State's access to renewable energy by expanding the geographic area from which it can draw power.”
