MISO and SPP said on Friday that a weak economic showing isn’t necessarily a dealbreaker in building transmission projects to accommodate generation from the RTOs’ overflowing interconnection queues.
Staffs told stakeholders Friday that their joint targeted interconnection queue (JTIQ) project has identified 11 projects in the upper Midwest that relieve most MISO-SPP constraints, but with a 0.33:1 combined benefit-to-cost ratio. The projects, tested with five other combinations of effective projects, are valued at $2.445 billion.
The grid operators also continue to consider a $424 million package that incorporates a long-distance, 345-kV line from Big Stone, S.D., to Alexandria, Minn.; a 345-kV line on the northeast side of Kansas City; and a transmission facility on the west side of Minneapolis. The multi-pronged project shows a combined 2.08:1 B/C ratio, but SPP experiences a negative 0.06:1 economic benefit ratio because of downstream impacts on other transmission lines.
If a project shows a negative B/C ratio to one RTO, it won’t automatically quash its chances of being approved, staff said.
MISO and SPP’s second round of evaluations tested 28 RTO-originated and stakeholder-submitted transmission solutions using their respective reliability and economic models. Eight solutions failed to relieve any transmission constraints, staff said.
The RTOs identified several projects crisscrossing South Dakota, Minnesota and Missouri during a first round of research under their joint targeted interconnection queue study. (See MISO, SPP Name Projects to Help Queue Troubles.)
Kelsey Allen, SPP’s lead engineer of transmission planning, said the JTIQ work began primarily as a reliability study, and the RTOs don’t intend to switch up projects now to chase higher adjusted production cost (APC) benefits.
The RTOs said they will have a final study report ready in December. Multiple stakeholders asked for an additional call to discuss project evaluation and selection before staff issues the final report.
MISO and SPP might use each footprint’s APC metric to determine cost allocation, increased transfer capability and real-time congestion reductions. The two could also assign some project costs to individual interconnecting generators based on avoided network upgrades.
SPP senior engineer Neil Robertson said the RTOs continue to collaborate on a final cost-allocation approach. He said it’s not easy to boil projects down to benefit dollars, so staffs may develop a rubric to divide costs that uses a scoring system for benefits like APC savings and new megawatts from the interconnection queues.
“I think anyone would want to see a simple benefit sheet in dollars,” he said. “You’re taking very different perspectives and traditional planning calculations and trying to compare them to one another. It’s apples to oranges.”
