MISO board approves ‘historic’ 8,000km transmission package

The US Midcontinent Independent System Operator (MISO) has approved a transmission package of 488 projects spanning 5,000 miles (approximately 8,000km).

The portfolio, which was unanimously approved by the MISO Board of Directors, includes 488 projects spanning more than 5,000 miles across 15 states in the MISO footprint. It includes local reliability and growth projects, the Long Range Transmission Planning (LRTP) Tranche 2.1 portfolio of projects, and the Joint Targeted Interconnection Queue (JTIQ) projects with Southwest Power Pool.

“This was truly a significant effort that required coordination and collaboration with our stakeholders, our neighboring grid operators and MISO staff,” said MISO CEO John Bear. “The energy landscape is quickly transitioning, and we must work with urgency to implement the changes that ensure reliability today and in the future.”

The 2024 MISO Transmission Expansion Plan (MTEP) includes the following:

• Local Reliability – 459 projects totaling 932 miles to support reliability in all 15 states across the MISO region. The $6.7B investment will improve infrastructure and meet load growth needs at the local level.
• LRTP Tranche 2.1 – 24 projects totaling 3,631 miles for regional projects in MISO’s Midwest subregion (Illinois, Indiana, Iowa, Michigan, Minnesota, Missouri, North Dakota, South Dakota and Wisconsin) and includes a 765kV backbone. The $21.8 billion portfolio has a cost-to-benefit ratio of 1.8-3.5 with benefits potentially exceeding $72 billion.
• JTIQ – five projects totaling 490 miles to enable generation on the MISO/SPP seam (Iowa, Kansas, Minnesota, Missouri, North Dakota, and South Dakota). The $1.6 billion investment will enable 28 GW of new generation.

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MISO said its “extensive” stakeholder process facilitated more than 300 meetings and captured feedback to arrive at a Tranche 2.1 portfolio that “delivers benefits exceeding costs.”

LRTP is a key part of MISO’s Reliability Imperative — the shared responsibility of states, utilities, members, and MISO to address challenges to electric reliability in the region, including generation fleet change, increasing extreme weather events, and other factors.

“These critical transmission infrastructure projects will strengthen the backbone of the greater Midwest region’s grid by enhancing system reliability and grid resilience to better withstand increasingly frequent and severe weather events, respond to load growth and support the generation fleet transition in the greater Midwest region,” ITC Holdings Corp said in a statement. “We applaud the work of MISO and its many stakeholders, who have worked collaboratively and transparently to approve this historic investment, and continue to invest, in our region’s critical transmission infrastructure. The benefits of MISO’s Tranche 2.1 portfolio will be realised for many generations to come.”

In July 2022, the MISO Board of Directors unanimously approved the Tranche 1 LRTP portfolio of new transmission projects. The $10.3 billion investment included 18 transmission projects in MISO’s Midwest Subregion. The grid operator found a benefit-to-cost ratio of at least 2.6, where benefits well exceed costs. The last time MISO approved projects close to this scale was in 2011, and that effort took four years. The Tranche 1 project portfolio, which was larger in terms of cost and miles, took half that time, said MISO. At the time, MISO said it was studying three additional portfolios (tranches), meant to improve interconnectivity and serve to further boost the reliability of the system.

The previous month, state regulators told MISO in a letter that it was time to review market signals and reliability requirements and to enhance collaboration between MISO, the states, and other entities responsible for resource adequacy. The letter, dated June 9, came a day before MISO released a joint report that said the region was projected to have a capacity deficit of 2.6 GW below the 2023 planning reserve margin requirement (PRMR). Similar to 2022, the capacity deficit in 2023 would be restricted to MISO North/Central, partially offset by exports from the South region.

Earlier this year, MISO shared an initial, draft proposal for a set of Tranche 2 transmission solutions – the second phase of the grid operator’s LRTP effort building on the investment in Tranche 1 through defining a set of new projects in its Midwest Subregion.

At the time, the original Tranche 2 plan had an anticipated cost between $17 – $23 billion, MISO said. Because of the impact of increasing load growth and the changing resource mix, the potential Tranche 2 portfolio featured 765kV lines, which MISO said would enable long-term value based on distance, cost, and land use in addition to reducing right-of-way permitting needs required in regulatory approval processes and helping address environmental concerns. After months of reform, MISO’s board voted to approve the updated Tranche 2.1.

A study from the Energy Department’s Lawrence Berkeley National Laboratory in 2022 found that interconnection costs for projects proposed in the MISO region were rising fast. The lab found that for projects that had completed all required interconnection studies, average costs nearly doubled for more recent projects relative to historical costs from 2000 through 2018. It said that for projects still actively moving through the queue, estimated costs more than tripled just between 2018 and 2022. It said that as of the end of 2021, MISO had more than 160 GW of generation and storage capacity actively seeking grid interconnection. This “active” capacity was dominated by solar (112 GW) and, to a lesser extent, wind (22 GW).

However, the lab said that most projects have historically withdrawn their applications, often in response to high interconnection costs. Roughly 24% of all projects requesting interconnection between 2000 and 2016 achieved commercial operation as of the end of 2021.

Originally published by Sean Wolfe on Power Grid International.