Building the Grid for What Comes Next
Ameren is rebuilding the transmission map across central and eastern Missouri as Grain Belt, new generation, and gigawatt-scale loads converge on one regional system
Aug 19, 2026
On August 19, Pike County Presiding Commissioner Bill Allen posted that someone “with Data Centers” had called him looking for help locating property in Pike County and asked him to sign a nondisclosure agreement. Allen refused, telling residents that he would not help find property under an NDA and that Pike County deserved to know when something like this was happening. We still do not know who called him, what company they represent, whether a site has been selected, or whether any electric-service request has been submitted. But the disclosure changes the context of something I was already watching closely: Pike County is sitting inside a rapidly expanding Ameren and MISO transmission network, at the same moment that gigawatt-scale data-center loads, new generation, battery storage, and major 345-kV projects are reshaping the grid around Montgomery, Lincoln, and northeast Missouri. So I went back through the MISO project database, Ameren’s existing-facilities records, the Montgomery–Callaway CCN, the Quinn testimony, and the new Eastern Missouri Grid materials to see exactly how Pike County fits into that system.
I went back through the MISO project database, Ameren’s existing-facilities records, the Montgomery–Callaway CCN, the Quinn testimony, and the new Eastern Missouri Grid materials. Pike County is not sitting off to the side of what is happening at Montgomery County or aside from the data center buildout in Missouri. It sits underneath and alongside the same expanding regional network—but at two voltage levels, and that distinction is crucial.
Quinn is being built directly on the existing Harley–Pike 161-kV line. Ameren’s sworn testimony says Quinn will initially be a three-terminal ring bus, with room for three additional future connections. Those future positions are specifically not included in the present project scope or cost. Construction is expected in 2027, with Millcreek following in 2028.
MISO’s current MTEP26 database says the same thing in slightly different language: Project 51302, a three-position 161-kV ring bus “capable of future expansion to 6-positions.”
Those three positions absolutely give Ameren future interconnection optionality there. They could eventually accommodate generation, storage, load, or additional transmission depending on what is studied and built.
But I do not have evidence that they have been reserved for a Pike County data center.
That distinction becomes even more important now that a Pike County official is publicly saying data-center site selection is occurring, because we know where they might be asking to plug in.
Here’s how the system actually fits together
Think of it as two overlapping electrical road systems.
The 345-kV network is the interstate highway system. That is where you put gigawatt-scale power movements and the enormous new loads we’re seeing at Elkhorn and Yoshi.
The 161-kV network is the regional highway system underneath it. Quinn, Harley–Pike and Pike–Peno Creek are on that layer.
They are not isolated from one another. Transformers connect the voltage levels at major substations, and power-flow changes on the 345-kV system can alter what happens on the 161-kV system. MISO’s Ameren facilities inventory, for example, identifies a 345/161-kV transformer at Montgomery rated 560 MVA. The same inventory establishes the existing Montgomery–Spencer Creek, Spencer Creek–Maywood, Rootbeer–Montgomery, Callaway–Montgomery, Burns–Montgomery and numerous 161-kV lines I’m researching.
The simplified topology looks like this:
NORTHERN MISSOURI 345-kV BUILDOUT
Denny —- Zachary ——– Maywood
/ \
/ \
existing 345 kV / \ NEW 345 kV
/ \ Maywood–Belleau
Spencer Creek \
| \
| Belleau
| |
| Rootbeer
| |
+— MONTGOMERY —–+
|
GRAIN BELT / TIGER |
| |
BURNS ========================+
| existing path +
| NEW double-circuit
|
McCredie/Callaway area
MONTGOMERY 345-kV HUB
/ \
/ \
Odyssey/Elkhorn Scarlet
| |
Elkhorn/Lumberjack |
\ /
\—- YOSHI —/
400 MW
———– 161-kV LAYER ———–
MONTGOMERY
[345/161 transformer]
/ \
Warrenton Guthrie
|
Big Creek
Lincoln County Pike County
Troy
|
Harley
|
QUINN ← Millcreek 250-MW BESS
|
Auburn
|
Cyrene
|
PIKE ——– Peno Creek ——– Spalding
| |
Calumet Hannibal West
|
Palmyra
|
Maywood area
That diagram simplifies ownership boundaries and some intermediate taps, but the relationships are drawn from Ameren/MISO facilities and project records.
There is an existing 345-kV route from Montgomery to Spencer Creek and from Spencer Creek north to Maywood. MISO’s transferred-facilities inventory identifies both.
Maywood is simultaneously becoming a much more consequential regional hub.
To its north and west, Ameren/ATXI’s Northern Missouri Grid Transformation is constructing more than 200 miles of new 345-kV transmission through the Denny–Zachary–Thomas Hill–Maywood project. Ameren says that project is intended to enable new generation and greater transfers into and out of Missouri.
And now MISO’s next regional transmission tranche comes south from Maywood through Pike County to Belleau.
That’s the Eastern Missouri Grid Transformation.
Ameren’s Pike County material says the Maywood–Belleau segment crosses Pike County and will replace roughly 27 miles of existing H-frame transmission structures. Up to 11 miles of new 345-kV corridor may be created in Pike County. Ameren says some new structures may carry both 345-kV and existing 161-kV circuits, with existing 161-kV circuits relocated onto the new corridor.
So this isn’t merely a 345-kV line flying over an unrelated Pike County system.
Ameren is literally considering rebuilding parts of the Pike County corridor so that 345-kV and 161-kV infrastructure occupy the same transmission structures/corridors.
That does not mean the two voltages are electrically connected everywhere they share a pole. They are separate circuits until a transformer ties them together.
But physically, this is a convergence.
And electrically, it increases the capacity and alternative routing available through the region.
Now look at the loop they’re constructing
This is the part that jumped out at me when I put the existing MISO facilities beside the new Eastern Missouri project.
Today, Ameren already has this 345-kV path:
Montgomery → Spencer Creek → Maywood
And this one:
Montgomery → Rootbeer → Belleau
Rootbeer is not simply “near” that line. Ameren’s own IRP says Rootbeer was created by splitting the existing Belleau–Montgomery 345-kV line for Split Rail.
Now MISO’s $881 million Tranche 2.1 Project 37 adds:
Maywood → Belleau → onward through the St. Louis-area network toward Sioux/Bugle.
MISO says this Missouri 345-kV project increases intraregional transfer capability and resolves constraints in the St. Louis region. MISO’s broader Tranche 2.1 plan was explicitly designed to enable significant new generation and load growth.
So you effectively get:
MAYWOOD
/ \
/ \
Spencer Creek NEW 345
| \
| BELLEAU
| |
| ROOTBEER
| |
+– MONTGOMERY —+
That’s a large high-voltage loop around this part of northeastern/eastern Missouri.
Loops matter because electricity no longer has only one route. If one element is out, power can flow around another side. They also increase transfer capability and make it easier to accommodate both new generation injections and new loads.
That’s why I am not thinking about Maywood–Belleau as merely “the Pike County transmission project.” It is one side of a regional 345-kV mesh whose other side already runs through Montgomery.
Then put Grain Belt on the southwest side of that mesh
At Burns, there is already an Ameren 345-kV connection toward Montgomery. MISO’s current facilities inventory already lists a Burns–Montgomery 345-kV circuit.
What Ameren is seeking in PSC Case EA-2026-0058 is another, much larger greenfield double-circuit 345-kV connection between the same Burns and Montgomery endpoints—roughly 28 miles, with both circuits designed for a 3,000-amp emergency rating.
Ameren expressly says those new circuits are required for Grain Belt’s Tiger Connector and the constraints MISO identified when studying that injection.
So Grain Belt is not just getting plugged into an existing skinny wire. The connection is causing Ameren to construct two additional 345-kV circuits into Montgomery and Ameren itself says the additional capacity will provide more rerouting flexibility and support future economic development.
Also, don’t let the project name confuse you: “Montgomery–Callaway Connector” does not mean Montgomery Substation → Callaway nuclear plant.
It means Montgomery County → Burns Substation in Callaway County.
Separately, there are already two 345-kV circuits directly connecting the Callaway Energy Center area to Montgomery. MISO’s Ameren facilities inventory lists both Callaway–Montgomery circuits.
So Montgomery has multiple major power paths coming into it from that direction.
That’s a serious bulk-power node.
Then Elkhorn and Yoshi build another loop around Montgomery
Now overlay the enormous new loads.
My research uncovering an Elkhorn filing says Ameren is constructing a new 345-kV substation for a 1,000-MW data center, using approximately 3.25 miles of double-circuit 345-kV line from Lumberjack to split the Odyssey–Montgomery line.
MISO now lists that as MTEP 50737, Appendix A approved.
Then MTEP 50738, Yoshi, adds another 400 MW. Ameren plans approximately 20 miles of double-circuit 345-kV between the Elkhorn/Lumberjack area and Yoshi and another approximately 10 miles from Scarlet to Yoshi.
So Yoshi isn’t just another dead-end customer connection.
It gives us this:
Odyssey / Montgomery side
|
Elkhorn / Lumberjack
|
~20 mi, double 345
|
YOSHI
|
~10 mi 345
|
SCARLET
Older MISO DPP planning material also identifies a Scarlet–Montgomery 345-kV corridor, including a planned rebuild of approximately 23 miles to 3,000-amp capability.
That means Elkhorn/Yoshi is effectively creating another high-capacity networked path around the Montgomery-area large loads, rather than attaching both customers at the end of one radial wire. And MISO is already preparing Montgomery itself for this scale: Project 51113 upgrades Montgomery’s 345-kV bus/terminal equipment to 4,000 amps specifically for load growth.
Now come back to Pike’s 161-kV system
This is where the commissioner disclosure becomes worth watching very closely.
MISO’s current MTEP26 list contains:
Project 51114 — Pike–Peno Creek 161-kV E3X.
Its description is explicit: increase the ampacity—the current-carrying ability—of Pike–Peno Creek.
And MISO lists the system need simply as:
“Load growth.”
That project is Appendix A approved.
I do not yet have public documentation naming the customer responsible for that load-growth requirement.
That is important. I would not write “the Pike data center is causing the Pike–Peno upgrade.” But the coincidence is now legitimately investigatory:
Pike County’s presiding commissioner publicly says data centers are looking at Pike County.
Ameren is preparing a new expandable 161-kV switching station on Harley–Pike.
MISO has approved an increase in Pike–Peno Creek’s carrying capacity specifically because of load growth.
And Ameren/ATXI is preparing a new 345-kV regional backbone through Pike County that can physically co-locate portions of the existing 161-kV system.
Those are confirmed facts that belong on the same timeline, even though the customer connecting them has not been publicly identified.
Quinn is therefore interesting—but for a different reason than Elkhorn
Elkhorn tells you exactly what it is:
1,000 MW. Data Center. 345 kV.
Quinn doesn’t.
Quinn currently tells you:
161 kV. 250-MW battery. Three initial terminals. Space for three future connections.
So I would treat Quinn as infrastructure optionality, not as evidence of a secret data-center connection.
Its significance is that Ameren is creating an expandable switching node on the Harley–Pike 161-kV corridor at precisely the time that the surrounding Pike/Lincoln transmission system is being reinforced.
The Harley–Pike system proceeds through Auburn and Cyrene to Pike. From Pike, the existing Ameren network continues through the very short Pike–Peno Creek section and onward toward Spalding, Hannibal West and Palmyra. MISO’s transferred-facilities database documents those facilities and the AECI interfaces along the route.
And at the northern end of that geography sits Maywood, the 345-kV hub being dramatically expanded by both the Northern Missouri and Eastern Missouri projects.
That doesn’t give us a simple:
Quinn → Maywood
electrical line.
It tells us that Pike’s 161-kV system sits beneath a rapidly expanding 345-kV regional backbone, with utility and cooperative interconnections between them.
There is also a generation side to Pike
This shouldn’t be overlooked either.
Peno Creek is not merely the name of a transmission node. It is already a generation location. And Quinn/Millcreek will add a major battery resource just south of Pike County.
That means this corridor is capable of doing both things: absorbing load and moving generation.
That matters enormously in the world Ameren and MISO are planning now, because giant data centers don’t simply need a wire from a power plant. They need a network capable of drawing from multiple resources, surviving contingencies, accepting renewable generation when available, dispatching storage, importing power over the bulk system, and drawing dispatchable generation when necessary.
That’s what this increasingly meshed topology provides.
So what does the Pike County disclosure change?
Pike County is now inside the physical expansion zone of the same high-capacity Ameren/MISO network being rebuilt around Montgomery’s large loads, new generation, storage, Grain Belt transfers and the eastern Missouri 345-kV backbone.
It isn’t yet evidence that a Pike data center has been assigned a wire.
But it absolutely means that a company conducting data-center site selection in Pike County would be looking at a county whose transmission geography is about to be materially more capable than it is today.
And that makes the timing of the site-selection disclosure genuinely important.
The larger pattern is becoming hard to ignore: build the transmission capacity, sign the load, use that contracted demand to justify more generation and grid expansion, and then use the stronger system to attract the next customer. Pike County is not proof alone of that cycle, but it is now squarely inside it. MISO has already approved a Pike–Peno Creek upgrade for load growth; Ameren has preserved three future interconnection positions at Quinn; a major new 345-kV corridor is coming through the county; and now the presiding commissioner says data-center interests are actively looking for land. We still do not know whether those facts converge on one project, but that is exactly why the public should be asking questions now—before land is secured, before loads enter MISO models, and before the conversation shifts from “Do we want this?” to “How do we accommodate what is already coming?”