ISO / RTO · MODELED TAPE
PJMDEM98.4GWFCST104.2GW+5.8LMP$49.36CONG$11.6●RES15.8%●TX8●MIXSrc: · · Upd Oct 10, 2026MISODEM76.5GWFCST84.9GW+8.4LMP$39.82CONG$18.7●RES17.4%●TX10●MIXSrc: · · Upd Oct 10, 2026ERCOTDEM58.9GWFCST66.1GW+7.2LMP$41.20CONG$9.8●RES7.6%●TX12●MIXSrc: · · Upd Oct 10, 2026SPPDEM31.7GWFCST36.2GW+4.5LMP$33.15CONG$6.4●RES21.6%●TX5●MIXSrc: · · Upd Oct 10, 2026CAISODEM27.2GWFCST33.5GW+6.3LMP$63.20CONG$13.9●RES11.4%●TX7●MIXSrc: · · Upd Oct 10, 2026NYISODEM16.1GWFCST19.0GW+2.9LMP$68.40CONG$10.3●RES14.1%●TX4●MIXSrc: · · Upd Oct 10, 2026ISO-NEDEM12.8GWFCST15.4GW+2.6LMP$57.10CONG$7.9●RES17.2%●TX3●MIXSrc: · · Upd Oct 10, 2026PJMDEM98.4GWFCST104.2GW+5.8LMP$49.36CONG$11.6●RES15.8%●TX8●MIXSrc: · · Upd Oct 10, 2026MISODEM76.5GWFCST84.9GW+8.4LMP$39.82CONG$18.7●RES17.4%●TX10●MIXSrc: · · Upd Oct 10, 2026ERCOTDEM58.9GWFCST66.1GW+7.2LMP$41.20CONG$9.8●RES7.6%●TX12●MIXSrc: · · Upd Oct 10, 2026SPPDEM31.7GWFCST36.2GW+4.5LMP$33.15CONG$6.4●RES21.6%●TX5●MIXSrc: · · Upd Oct 10, 2026CAISODEM27.2GWFCST33.5GW+6.3LMP$63.20CONG$13.9●RES11.4%●TX7●MIXSrc: · · Upd Oct 10, 2026NYISODEM16.1GWFCST19.0GW+2.9LMP$68.40CONG$10.3●RES14.1%●TX4●MIXSrc: · · Upd Oct 10, 2026ISO-NEDEM12.8GWFCST15.4GW+2.6LMP$57.10CONG$7.9●RES17.2%●TX3●MIXSrc: · · Upd Oct 10, 2026
SMStock & Milster

Market Intelligence / ERCOT · SPP · Western Interconnection

Three power markets.
Three different infrastructure realities.

ERCOT, SPP and the Western Interconnection represent fundamentally different power, transmission, congestion, interconnection and development environments. Stock & Milster converts those differences into decision intelligence for infrastructure, industrial and data-intensive investment.

Infrastructure changes the decision.Footprints approximate · corridors conceptual · not actual line routes
Public DataModeled IntelligenceIllustrative ScenarioClient / NDA Data

01 — Market Command Center

Where the three systems are — and how they differ.

Illustrative ScenarioSource: U.S. Census state boundaries (us-atlas); footprints by majority stateAs of: October 2026Footprints are approximate — real boundaries follow utility service territories and cross state lines. Corridors are conceptual.

Intelligence panel

ERCOT

Manages the grid for most of Texas as a largely self-contained interconnection, with limited synchronous ties to neighboring systems.

Market structurePublic Data
Energy-only market design; no centralized capacity market. Most of the system is not subject to FERC wholesale-rate jurisdiction; oversight sits with the PUCT.
TransmissionPublic Data
Planned through ERCOT and the PUCT; costs broadly socialized across ERCOT load. Major buildouts are under discussion for West Texas and Permian electrification.
Load growthPublic Data
Large-load requests — data centers, industrial electrification, oil-and-gas electrification — have driven sharp upward revisions in ERCOT's own long-term forecasts.
CongestionModeled Intelligence
Concentrated where West and South Texas generation must reach the eastern load centers; location-specific pricing makes congestion a site-level economic variable.
InterconnectionPublic Data
Generally faster generator interconnection than other organized markets; large-load interconnection is now subject to evolving study and policy requirements.
Resource adequacyPublic Data
Managed through price signals, reserve products and policy interventions rather than a capacity market. Winter and evening net-peak conditions are the focus.
Utility structurePublic Data
Competitive retail in much of the region alongside municipal utilities and cooperatives with different rules; the wires owner matters as much as the market.
Large-load pressureModeled Intelligence
High and geographically clustered — DFW, Austin–San Antonio and the Permian rank among the most contested pockets.
Development velocityModeled Intelligence
Fast relative to peers — and that speed can mean competing loads reach the same substation first.
Capital / timing riskModeled Intelligence
Shifting from 'can we connect' to 'when, at what upgrade cost, and under which curtailment conditions'.
Public DataSource: ERCOT — About ERCOT (opens in new tab)As of: October 2026Qualitative characterizations; no live statistics. Modeled entries are Stock & Milster analysis.

02 — ERCOT Intelligence

ERCOT
The speed market.

ERCOT manages the grid for most of Texas. Unlike the other organized markets, it operates as a largely separate interconnection with limited ties to neighboring systems, an energy-only market design, and state rather than federal oversight for most wholesale activity. Projects can move fast — and so can the loads competing with them.

Dallas–Fort WorthHoustonAustinSan AntonioPermian BasinCorpus Christi
Illustrative ScenarioSource: Stock & Milster conceptual layers on public geography; see ERCOT planning (opens in new tab)As of: October 2026Layer placements are conceptual. ERCOT's footprint excludes parts of the Panhandle, El Paso and East Texas served by other systems.

Power path

  1. Generation

  2. Transmission

  3. Constraint

  4. Load center

  5. Site decision

A constraint anywhere on the path determines what the site can actually receive — and when.

What executives need to know

Where is load growing?

Large-load interconnection requests cluster around DFW, Austin–San Antonio, the Houston industrial corridor and the Permian.

Where is transmission being added?

Planning efforts focus on moving West Texas supply east and on serving Permian electrification; approval does not mean energization.

Where could congestion alter economics?

Between West/South Texas generation and eastern load; nodal pricing turns that constraint into site-level price exposure.

Where can infrastructure timing affect development?

Wherever a site depends on a substation or line upgrade that has not yet been approved, sited or built.

Where are major loads competing for grid capacity?

At shared substations around metro data-center clusters and in the Permian, where electrification and industrial demand overlap.

Which assumptions require utility confirmation?

Available capacity at the point of delivery, upgrade scope and cost, energization date, and any curtailment or flexibility conditions.

03 — SPP Intelligence

SPP
The transmission market.

A vast central-U.S. system where geography, generation, transmission expansion, congestion and new industrial load can produce materially different infrastructure conditions from one corridor to another.

PanhandleOklahoma CityTulsaWichitaKansas CityOmahaSioux FallsBismarck
Illustrative ScenarioSource: SPP footprint (core states shown); corridors conceptual (opens in new tab)As of: October 2026SPP's footprint also covers portions of neighboring states; consult SPP for the official footprint and transmission plans.

Corridor intelligence

Power
Resource-rich western supply area
Transmission
Long east-bound paths; planned expansions in portfolio
Load
Metro and industrial demand at the eastern end
Constraint
West-to-east export limits
Timing
Depends on planned line in-service dates
Decision impact
Site near load vs near supply — weigh delivery risk against cost
Modeled IntelligenceSource: Stock & Milster corridor frameworkAs of: October 2026Qualitative; site conditions require utility and SPP confirmation.

04 — Western Interconnection / WECC

Western Interconnection
The geography market.

WECC is the Regional Entity for the Western Interconnection — it oversees bulk-power reliability. It is not an ISO/RTO and does not run a centralized market like ERCOT or SPP. The West is served by many balancing authorities and utilities, connected across mountains and deserts by a limited set of long transmission paths.

Distance+Terrain+Transmission+Load=Infrastructure risk
CASCADESSIERRA NEVADAROCKY MOUNTAINSWASATCHSeattlePortlandBay AreaLos AngelesLas VegasPhoenixSalt Lake CityDenverBoiseAlbuquerqueReno
Illustrative ScenarioSource: WECC — Western Interconnection overview; terrain stylized (opens in new tab)As of: October 2026Relief is a stylized rendering, ridgelines approximate. Corridors conceptual; the Western Interconnection also spans western Canada and northern Baja California.

05 — Three-Market Comparison

ERCOT vs SPP vs Western Interconnection.

Summaries, not substitutes for market rules. Tap or hover dotted terms for definitions.

ISO for most of Texas; overseen by the PUCT and Texas Legislature
Energy-only, nodal real-time and day-ahead
Transmission planning
ERCOT / PUCT; costs socialized within ERCOT
Geographic scale
One state, largely isolated system
West/South supply to eastern load
Relatively fast; large-load rules evolving
Large-load growth
High, clustered
Industrial exposure
Petrochemical, refining, oil-and-gas electrification
Data-center pressure
High near metros and new campus regions
Utility complexity
Wires companies, munis, co-ops; retail choice in parts
Development considerations
Speed vs competing load at shared substations
Primary diligence question
Who reaches this substation first, and on what terms?
Public DataSource: FERC, ERCOT, SPP and WECC public descriptions (opens in new tab)As of: October 2026Structural characterizations simplified for executive reading; verify specifics against the operator's current rules.

06 — Follow the Megawatt

From generator to decision — where it can break.

What can go wrong

Insufficient transformer or local delivery capacity.

What Stock & Milster investigates

Does infrastructure have sufficient capability for the proposed load and timeline?

Decision impact

Development timing / upgrade requirement / alternative location analysis

In ERCOT, the typical failure point is the substation and the queue of competing large loads — speed cuts both ways.

Modeled IntelligenceSource: Stock & Milster diligence frameworkAs of: October 2026

07 — Infrastructure Pressure

Where power meets demand.

Available generation does not equal deliverable power at a particular site. As demand drivers stack on the same nodes, pressure concentrates on the local substations and lines that serve them.

Illustrative ScenarioSource: Stock & Milster conceptual overlayAs of: October 2026Ring size reflects how many demand drivers are assigned to a node in this illustration — not measured load.

08 — Executive Decision Matrix

The grid is not the decision.
The consequence is.

Signal

Load growth

Infrastructure effect

Local capacity pressure

Financial consequence

Upgrade / timing exposure

Executive decision

Locate · stage · negotiate · defer

Signal

Transmission congestion

Infrastructure effect

Constrained delivery

Financial consequence

Price / timing uncertainty

Executive decision

Compare alternative corridors

Signal

Interconnection delay

Infrastructure effect

Project schedule risk

Financial consequence

Carrying-cost exposure

Executive decision

Restructure development timeline

Signal

Competing large loads

Infrastructure effect

Shared substation capacity

Financial consequence

Upgrade cost allocation risk

Executive decision

Secure position or shift site

Signal

Regulatory change

Infrastructure effect

Altered large-load rules

Financial consequence

Curtailment or cost terms

Executive decision

Build flexibility into the plan

Modeled IntelligenceSource: Stock & Milster decision frameworkAs of: October 2026

Evaluating a site, acquisition or load decision in ERCOT, SPP or the West?

Stock & Milster advises on the decision. We do not sell the project, broker power or build infrastructure.