Dive Brief:
- The Midcontinent Independent System Operator is proposing an up to $23 billion transmission expansion that would create a 765-kV backbone across its Midwest region, according to an initial draft portfolio released on Monday.
- MISO expects it will refine its Long Range Transmission Planning, or LRTP, Tranche 2 proposal as it considers alternative projects offered by utilities and independent transmission developers, and incorporates an economic analysis in its assessment.
- “The draft Tranche 2 map … shows good progress towards identifying a portfolio of lines that can support MISO states and utilities in meeting their clean energy goals, while also improving reliability and accommodating load growth,” Natalie McIntire, a senior advocate at Sustainable FERC Project, said in an email. “MISO’s inclusion of a number of 765-kV lines is key to a robust buildout of the grid of the future.”
Dive Insight:
MISO’s proposal builds on its roughly $10.3 billion Tranche 1 plan, approved by the grid operator’s board in mid-2022, as well as the $1.7 billion Joint Targeted Interconnection Queue projects along MISO’s seam with the Southwest Power Pool.
MISO’s initial $17 billion to $23 billion Tranche 2 plan is designed to handle what the grid operator expects its system will look like in 2042 under a scenario called Future 2A found in its most recent Futures Report. The scenario is based on utility resource plans and state energy goals.
Under that scenario, MISO expects it will see 369 GW in generator additions, 103 GW of power plant retirements and a 96% cut in carbon emissions by 2042. It expects its net peak load will grow to 145 GW in that year — up from a record peak of 127 GW in 2011 — and wind, solar and energy storage will provide about 83% of its electricity.
Without the proposed transmission, those changes would lead to overloads and generator curtailments across its Midwest region, according to a presentation set to be discussed at a March 15 LRTP workshop. MISO also expects it will need to be able to transfer power between its Eastern and Western regions.
“To meet changing resource needs and projected load increases for the MISO Midwest region, the final portfolio will enable a reliable and efficient transmission system while minimizing land use through a focus on 765-kV transmission,” MISO said in the presentation.
The portfolio centers on building a 765-kV transmission “highway” in MISO to “maximize value based on land use, line distances, transfer levels and costs,” the grid operator said.
Permission granted by Midcontinent Independent System Operator
The Clean Grid Alliance, a trade group for renewable energy developers, is disappointed the initial draft doesn’t include high-voltage direct current, or HVDC, projects, which could help ease grid stability issues that are occurring on parts of MISO’s system, according to Beth Soholt, the group’s executive director, and a MISO Advisory Committee member.
“I’m curious to hear from the transmission owners,” Soholt said Wednesday. “Did MISO get it right, or do they think MISO missed something?”
The Sustainable FERC Project believes the Tranche 2 portfolio should include HVDC lines, which could bring “unique” benefits to moving power across the northern part of MISO’s footprint, according to McIntire.
MISO is accepting alternate transmission proposals through April 5 and will consider them as it refines its analysis on its initial plan.
The Clean Grid Alliance intends to press for more East-West transfer capacity across MISO, according to Soholt.
Soholt said she expects the proposed portfolio’s costs to be debated among MISO stakeholders and is “eagerly awaiting” to see MISO’s pending expansion of the benefits metrics it will use to assess the transmission lines’ value. MISO used six metrics, including congestion and fuel savings, to help assess the value of its Tranche 1 portfolio and is considering using additional ones for Tranche 2.
“The benefits and values we get from these lines is just enormous,” Soholt said, pointing to the need to wheel power during extreme weather.
Transmission costs are a relatively small part of electricity bills, according to Soholt. She said they account for 11% of her Xcel Energy electric bill, followed by distribution at 40% and generation at 49%.
In the weeks ahead as MISO staff refines its proposal and stakeholders review it, “the business case needs to get out there,” Soholt said. “State regulators need to understand it.”
When the Tranche 2 process nears completion, MISO intends to begin developing a Tranche 3 transmission portfolio for its southern region. Cost allocation discussions for that effort are underway in MISO’s Regional Expansion Criteria and Benefits Working Group.
Later, MISO plans to launch a Tranche 4 initiative aimed at increasing transfer capacity between its Northern and Southern sections.
