TWITTER_THREAD

NiyerEnergy argues PJM's capacity auctions flipped from roughly a decade-low…

2026-02-02 · 02:13 UTC ·NiyerEnergy ·4 min read

Brief

NiyerEnergy frames PJM's latest capacity auction outcome as a structural break in how the market values reliability, not just a sudden load-growth story. The thread argues that a one-year jump from near-floor prices to the auction cap reflects several overlapping shocks: new data-center and native demand, Dominion's return with a roughly 6 GW short position, thermal retirements, and especially changes in accreditation methodology that re-rated both renewables and thermal plants using ELCC concepts. In the author's telling, PJM spent 15 years shifting from coal toward gas while appearing adequately supplied on installed thermal capacity, but newer rules imply the system was less reliable than legacy metrics suggested. The result is that a relatively small 5-7 GW swing can dominate prices in a market sitting near the edge, which is why the author sees current cost spikes as partly a market-design problem tied to ELCC plus pay-as-cleared auctions, not simply a data-center problem.

Why it matters

NiyerEnergy argues PJM's capacity auctions flipped from roughly a decade-low pricing regime in 2024/2025 to the auction cap in 2025/2026, calling it a market-design regime shift rather than a story driven only by early data-center load growth.

Key details

  • The thread attributes the price spike to multiple simultaneous factors: some data-center and native load growth, Dominion re-entering the market with an estimated 6 GW deficit, thermal retirements, and rule changes that moved reliability accreditation toward marginal ELCC and from UFORd to ELCC for thermal resources.
  • The author says PJM's old framework suggested the system stayed tight but still broadly safe until around 2031, while the new accreditation rules imply the region may have effectively been in a reliability 'danger zone' for much of the last 10 years despite low capacity-market prices.
  • A key quantitative claim is that the floor-to-peak move is on the order of 7 GW, so any supply-or-demand change larger than about 5-7 GW could plausibly be blamed for most of the cost increase; the author explicitly argues this makes 'blame data centers' an incomplete explanation.
  • NiyerEnergy's main critique is that marginal ELCC may be appropriate for valuing additions and retirements, but its interaction with PJM's pay-as-cleared auction design is producing dysfunctional price outcomes.
Cleaned source text

title: @NiyerEnergy: I'm going to start PJM posting. Do not be alarmed. I will speak in a form of eff... (Thread, 10 tweets)

author: NiyerEnergy

content_type: twitter_thread

published: 2026-02-02T02:13:00+00:00

source_url: https://x.com/NiyerEnergy/status/2018145598818373919

word_count: 864

Thread by @NiyerEnergy

Tweet 1/10

I'm going to start PJM posting. Do not be alarmed. I will speak in a form of effectively gibberish for 99.95% of the general population. It's likely a form of insanity, the best of us have gone too deep and never returned. The changes between the auctions of 2024/2025 and 2025/2026 are relevant to our present moment, as it was a regime shift from floor to peak in the capacity markets. Feel free to disagree with these takes, if you have the knowledge! /1

Tweet 2/10

You can see here the big moment I'm talking about. We shift from lowest it's been for like 10 years (e.g. retire capacity) to the literal cap in one year. A LOT happened in that year, way more than the early ramp of data centers! /2

Tweet 3/10

I will give you 10 good ones: 1. Some datacenter and native load growth 2. Dominion re-enters the market, with like a 6 GW deficit 3. Thermal retirements 4. Shift to marginal ELCC, changing the way resources are considered reliable. 5. Shift from UFORd -> ELCC for thermals 6. On

Tweet 4/10

There are a lot of moving parts. Do not be afraid, the PJM market cannot hurt you unless you are one of 67 million Americans. Basically you can see over the past 15 years, PJM has been doing a coal-> gas push. If you look at the installed capacity, is more than enough thermals

Tweet 5/10

In the old world, you would take off another slice based on outages and maintenance and other stuff. We are getting tight but still in the safe zone until like 2031 ish. We are not in that world! /5

Tweet 6/10

After all the edits and shifts, not only are we tight, but actually if we backcast things, the new rules argue we actually have been in the danger zone for the last 10 years when the market was effectively below the floor we've set on cap markets. Renewables pretty much don't

Tweet 7/10

The trad narrative is to blame data centers for existing (and they do!) but the floor to peak is like 7 GWs and we are apparently right on the edge. Anything that changes supply/demand more than 5-7 GWs could be "attributed" 100% of the cost increases. Queue delays, coal

Tweet 8/10

My personal view is that marginal ELCC makes sense to value additions and retirements, but fundamentally it's interaction with pay as cleared auctions is leading to dysfunction. "Marginal price signals" are a sacred form in the mind of the priestly market designers, but it's

Tweet 9/10

Anyway views my own, feel free to rip me apart here I'm still learning. DMs are open if you want to debate market design. /Done

Tweet 10/10

Posted: 2026-02-02T02:41:00.000Z

Engagement: 15 likes, 0 retweets, 3 replies

Discussion (14 replies)

@Ember421 (4 likes)

My view is that the market system exists to get the resources online that are actually needed to provide the energy and capacity demanded. But given our broader economic system, this basically boils down to mechanisms to get stuff financed.

@Richard15322800 (3 likes)

What's been interesting to me in this winter storm was the feedstock issue. As you have coal->gas, now gas prices/demand are much more tightly correlated to demand/gen. Where once you had to fuels, you now just have increasingly one (and that one is harder to store)

@BateGerald (1 likes)

All of this is downstream of the ix queue which exists to shred capital In a functioning system, the queue is a pipeline that allows supply to respond to changes in price, and get development going. Look at the queue, barely 20% of projects actually make it through

@ChickenMon3000 (1 likes)

Sounds like we shouldn’t have gotten rid of coal

@tobe_duru (1 likes)

"welcome to the PJM rabbit hole"

@oldF500cfo

What is crazy is that PJM is sitting on one of the largest gas field in the world. They should be encouraging more cracking plants to consume ethane and use methane for power generation. Also need to put interruptible loads like crypto mining in place.

@markovschainsaw