NERC's long term assessment spotlights MISO.
NERC’s 2024 LTRA relies on data from MISO’s Nov 2023 LOLE Study. Upcoming updates, including MISO’s Q1 2025 Outyear PRM Results and the June 2025 OMS-MISO Survey, will provide a more accurate picture.
The North American Electric Reliability Corporation (NERC) released its 2024 Long Term Reliability Assessment (LTRA) last month. The headline is, the Midcontinent Independent System Operator (MISO) has a “high risk”, meaning it is at a risk of shortfalls occurring during normal peak conditions. Lot of regions including MISO’s neighbors: SPP, PJM and others such as CAISO, ERCOT, NPCC are at an “elevated risk”, meaning there is a risk of shortfalls occurring during extreme conditions.
Source: NERC 2024 LTRA
NERC states the MISO region is high risk because “Resource additions are not keeping up with generator retirements and demand growth. Reserve margins fall below Reference Margin Levels (RML) in winter and summer.”
This explains why MISO has an initiative called Expedited Resource Adequacy Study (ERAS). I think MISO is following PJM’s example, read more here.
Leaving MISO’s ERAS efforts aside, the NERC 2024 LTRA shows this for MISO’s future planning reserve margins -
Source: Page 41, NERC 2024 LTRA.
The Reference Margin Level % of 18.1% in 2025, 18.5% in 2026, 18.9% in 2027, 19% in 2028 and 19% in 2029, shown in the NERC LTRA report are on the Installed Capacity (ICAP) basis, not the Unforced Capacity1 (UCAP) basis, which the OMS MISO Survey shows. The distinction is important because UCAP accounts for generator reliability by factoring in forced outage rates, providing a more realistic measure of resource adequacy compared to ICAP.
Source: Slide 7, 2024 OMS-MISO Survey Results
Please note that the 2024 OMS-MISO Survey Results were released in June 2024, and the NERC 2024 LTRA was released in December 2024. So, there could be a data lag.
However, the NERC report refers to “It is important to note that there is 56 GW of generation with signed generation interconnection agreements that are yet to come online as of July 5, 2024, so there is an opportunity to accelerate installation speeds.” [Pg 43, NERC 2024 LTRA] So, the data lag may not be huge either.
Both NERC and OMS-MISO Survey report 2.7 GW shortfall2 [3]
I had previously written about what changes went into 2024 OMS-MISO Survey here.
The NERC 2024 LTRA report counts only 8,205 MW of demand response [pg 41], but MISO has over 12,000 of supply-side demand response.
MISO’s 2025-2026 Loss of Load Expectation Study report shows 1,900 MW of firm import support from external regions but NERC 2024 LTRA only shows 1,320 MW.
Source: MISO LOLE Report
Comparing the above table with NERC 2024 LTRA - MISO projects a 2025 summer peak demand of 123,576 MW, whereas NERC projects 122,328 MW. MISO estimates an installed capacity of 141,908 MW for 2025 summer, whereas NERC estimates 128,520 MW. MISO expects a PRM of 15.7% but NERC is showing 17.0%.
Source: Pg 41, NERC 2024 LTRA
It looks like NERC 2024 LTRA is using MISO’s 2024-2025 LOLE Study report published in November 2023 -
Source: Page 35, MISO 2024-2025 LOLE Report
Comparing the above table with NERC 2024 LTRA - MISO projected a 2024 summer peak demand of 124,669 MW, whereas NERC projects 122,328 MW. MISO estimated an installed capacity of 150,187 MW for 2024 summer, whereas NERC estimates 128,520 MW. MISO expected a PRM of 17.7% but NERC is showing 17.0%. So, this leads me to believe that some data lag exists in the NERC 2024 LTRA report because the latest values from the MISO 2025-2026 Loss of Load Expectation Study report are not included in the NERC report.
An additional table from the MISO 2024-2025 LOLE shows the exact values of Reserve Margin mentioned in the NERC 2024 LTRA. See below and compare it to the NERC table shown earlier.
Source: Page 60, MISO 2024-2025 LOLE Report
This leads me to conclude the following:
NERC’s 2024 LTRA likely relied on data from MISO’s LOLE Study released in November 2023. However, the Outyear PRM results in that report were updated in Q1 2024, and since then, MISO released its latest LOLE Study in November 2024.
As a result, the NERC 2024 LTRA does not reflect the most recent updates to installed capacity, demand response, and import projections for future years.
When MISO releases the updated Outyear PRM Results in Q1 2025, we will have a clearer picture of the next five years.
Additionally, the OMS-MISO Survey for 2025, expected in June 2025, will provide another valuable snapshot.
Given these timelines and forthcoming updates, I wouldn’t place too much emphasis on the findings of the NERC 2024 LTRA report for MISO at this stage.
Source: Page 62, MISO 2025-2026 LOLE Report
The installed capacity less forced outage rates. Capacity Resources are quantified by applying forced outage rates to installed capacity values (ICAP) to calculate the Unforced Capacity value (UCAP) for the resource. Source: Slide 58, https://cdn.misoenergy.org/LOLE%20101%20Training624875.pdf
“MISO’s delays in generator construction result in a 2.7 GW shortfall.” Pg 43, NERC 2024 LTRA
“Results indicate a potential surplus of 1.1 GW to a deficit of 2.7 GW for the summer of PY2025/26, depending on critical, yet uncertain, drivers such as the pace and quantity of new resource additions and projected resource retirements.” 2024 OMS-MISO Survey, Slide 2
Nice commentary, Rao. As usual. Interesting to me that lag is not noted by the report. Good find for Q1 2025.