MISO expects the revamp of its transmission planning futures will be done by November and will yield an extra scenario dedicated to slow-moving generation construction.

The RTO said load growth from data centers, AI computing and domestic manufacturing makes it clear its current trio of 20-year futures that form the basis of its long-term transmission planning is outdated. It also said it foresees the potential for hydrogen production demand in later years of the futures.

MISO used the three futures it’s now retiring to rationalize about $32 billion in transmission investment between its first and second long-range transmission plan (LRTP) portfolios. It plans to use its upcoming revised futures to chart a third LRTP portfolio for MISO Midwest. (See MISO Pauses Long-range Tx Planning in 2025 to go Back to the Futures.) MISO established its current futures in 2019 and last updated them in 2022.

“It’s critical to do this now because we’re at another inflection point,” MISO Senior Vice President of Planning Jennifer Curran said during Feb. 28 Futures Redesign Workshop, the first in a series with stakeholders to modernize the futures.

Curran said though MISO has warned several times about inflection points over the years, members’ estimated load growth makes the RTO’s latest take-notice just as legitimate.

Curran said load growth trajectories are outstripping what’s contemplated in the existing futures. She also said MISO plans to add a fourth future to contemplate what happens if generation additions remain sluggish, as they have in recent years, noting that MISO needs to understand “what happens if things don’t pick back up really soon.”

She said MISO hopes to emerge with a new set of futures within nine months, something she acknowledged would be an uphill battle.

“It’s of critical importance to get these updates as soon as we can,” she said.

Director of Economic and Policy Planning Christina Drake said MISO decided its members’ integrated resource planning, the footprint’s load growth, continuing decarbonization and generation retirements will be the “load-bearing walls” of the new set of futures.

MISO’s proposed four, 20-year futures include:

• • A “lower load growth” scenario, in which demand projections don’t materialize due to an economic slowdown, and some utilities and states’ emissions reductions announcements are unrealized.
  • A “stated policy” future, in which estimated trends like reindustrialization, data center growth and electrification hold steady while members expand generation and meet their current emissions goals.
  • A “higher load growth” future, in which supply needs inch beyond today’s forecasts driven by high-powered load.
  • A “supply shift” future, in which MISO said “supply frictions” limit the pace of generation additions and load growth has to be managed through existing generation and demand-side resources.

While the first three futures largely use the logic MISO employed in its existing futures (slow, medium and fast-paced options), Drake said MISO must work through the “finer details” of its new fourth future. MISO also anticipates retirement delays and more demand-side resources in addition to unfulfilled emissions reductions targets.

Across all futures, MISO will apply an age-based retirement assumption to generation if members haven’t specified a retirement date. That age-based date will arrive years sooner for coal and gas units in the more progressive “stated policy” and “higher load growth” futures.

This time around, MISO will transition to Energy Exemplar’s more sophisticated PLEXOS tool to model generation expansion. It’s retiring use of the Electric Power Research Institute’s Electric Generation Expansion Analysis System, which MISO said was hitting the limits of the variables it can simulate as the system becomes more complex.

Curran warned the work could feel “uncomfortable” for some stakeholders because change is difficult. She stressed MISO’s goal is to land on a range of possibilities and asked that stakeholders not get hung up on modeling precision.

“It can be hard to predict next year, much less 20 years out. I can’t say it enough that it’s the bounds that are important,” she said.

WPPI Energy’s Steve Leovy said it was disconcerting MISO seems to be abandoning accuracy to establish its bookends.

Kavita Maini, a consultant representing MISO industrial customers, agreed and asked MISO to “not trade speed for accuracy.”

WEC Energy Group’s Chris Plante said he was “fearful” MISO would use its search for general bookends to justify omitting sensitivities or robustness testing.

Curran said she expects there will be some variables that won’t meaningfully change MISO’s transmission expansion needs.

“I guarantee that there are going to be things that we assess as immaterial that stakeholders will disagree with,” she said. “I will caution that one person’s crazy is another person’s reasonable.”

MISO also will include energy adequacy assessments as part of its futures. Drake said MISO hopes its adequacy assessment will support its states — which hold resource-planning power — in making informed decisions.

Maini asked if MISO has considered that its members will relax some carbon-cutting endeavors in resource plans due to the Trump administration’s standpoints on clean energy. She also asked if MISO has analyzed how trends might change if the Inflation Reduction Act is axed.

Drake said the Inflation Reduction Act might not have as much bearing on planning as some might assume. She said MISO’s research to date has found that member plans would predominately set the futures’ course.

“It was basically not as impactful as what was coming through our member plans,” Drake said.

MISO plans to discuss other assumptions at upcoming workshops. It plans to hold another Futures Redesign Workshop with stakeholders March 19.

Multiple stakeholders urged MISO to allow them to record and transcribe the workshops so others at their organizations can keep up with futures development. The grid operator prohibits anyone from recording meetings, save for a few self-recorded workshops throughout the year. It has opted not to allow futures workshops in its archives.