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IL — Power Infrastructure Updated January 8, 2026

Illinois

MISO/PJM Natural Gas Nuclear Solar Wind Storage Data Center PPAs Queue Bottlenecks Transmission Constraints

Overview

Illinois sits at the intersection of two major grid operators — MISO in the downstate and western regions, PJM in the Chicago metro — and is building generation and transmission at scale to meet rising demand. The state’s power buildout includes a 1.1 GW natural gas plant under permit, a 20-year nuclear PPA with Meta for the full output of the Clinton station, and hundreds of megawatts of solar, wind, and battery storage projects under construction. MISO and PJM are both investing billions in transmission upgrades across Illinois, but interconnection queues are backed up and timelines stretch years beyond tariff schedules.

Generation Projects

Natural Gas

EmberClear’s Lincoln Land Energy Center received its construction permit from the Illinois EPA in 2022 and remains the state’s largest named gas project in the current pipeline.

  • Lincoln Land Energy Center (Sangamon County): A 1,100 MW combined-cycle plant near Pawnee, targeting mid-decade in-service. The project is positioned to provide firm power for large industrial and data center loads.[1]

Nuclear

Constellation’s Clinton station is not a new build, but its life-extension and uprate are the most consequential near-term nuclear action in Illinois.

  • Clinton Clean Energy Center (Constellation): Under a 20-year PPA with Meta beginning June 2027, the 1,121 MW nuclear plant will undergo relicensing, continued operations, and a 30 MW uprate. This agreement supports firm, always-on power for large loads.[2]

Solar

Illinois has multiple utility-scale solar projects under construction, led by Vistra and RWE.

  • Pulaski Solar (Pulaski County): Vistra began construction on this 405 MW facility in 2024, targeting 2026 in-service. The project is tied to a long-term PPA and represents one of the state’s largest solar builds.[3]
  • Casey Fork Solar (Jefferson County): RWE started onsite construction on its first Illinois utility-scale solar project, a 150 MWac facility, in 2024.[4]

Wind

Avangrid is expanding its Illinois wind footprint with a new 153 MW project in La Salle County.

  • Osagrove Flats wind farm (La Salle County): A 153 MW wind project with 34 turbines, adding to the state’s renewable capacity available for utility supply or PPA contracting.[5]

Transmission and Grid

Illinois is the site of major transmission investment by both MISO and PJM, with billions of dollars committed to high-voltage upgrades and interregional ties.

MISO Long-Range Transmission Planning

MISO’s multi-tranche transmission buildout is central to Illinois’ long-term grid capacity.

  • Tranche 2.1 (approved December 2024): A 3,631-mile, 765 kV backbone portfolio totaling $21.8 billion across 24 projects and 323 facilities in the MISO Midwest subregion, targeting 2032-2034. Most of Illinois sits in this subregion, so these lines and substations are critical to moving power to large loads.[6]
  • Tranche 1 (approved 2022): The earlier portfolio totals $10.3 billion across 18 projects, with ongoing regulatory approvals and buildout in downstate and west-central Illinois.[6]

PJM Regional Transmission Expansion Plan

PJM’s 2024 Illinois State Infrastructure Report indicates ongoing high-voltage and substation upgrades in northern Illinois.

  • PJM RTEP investments (ComEd zone): The 2024 RTEP project total for the PJM portion of Illinois is approximately $1.533 billion, supporting steady grid expansion where many data centers cluster.[8]

Interregional Projects

The SOO Green HVDC Link is a merchant, underground transmission line connecting the MISO and PJM regions.

  • SOO Green HVDC Link: A 2,100 MW, 350-mile underground line designed to move Iowa wind power into the PJM market. The interregional tie is relevant to Illinois because PJM’s ComEd zone and MISO’s Ameren zone sit on either side of the project’s endpoints.[7]

Battery Storage

Illinois has several utility-scale battery storage projects in development, with hybrid solar-plus-storage designs gaining traction.

  • Little Prairie Hybrid (Champaign County): BayWa r.e.’s project pairs 163 MW of solar with 135 MW of battery storage, supporting fast-ramping capacity that can firm renewable output for 24/7 loads.[9]
  • Vistra solar + storage portfolio: Vistra requested two-year extensions for Illinois projects totaling 833 MW due to supply-chain delays. The portfolio signals a sizable utility-scale storage pipeline still waiting on equipment and interconnection milestones.[10]

Data Center Power Agreements

Illinois has one major PPA tied directly to a tech company’s data center power needs.

  • Meta + Constellation (Clinton nuclear): Meta signed a 20-year agreement for the full output of Constellation’s 1,121 MW Clinton Clean Energy Center, beginning in 2027. This is the clearest Illinois-based, large-load PPA tied to a major tech company and aligns with data center-scale demand for firm power.[2]

Interconnection Queue

Illinois faces significant queue delays and backlog in both the MISO and PJM regions.

PJM Illinois (ComEd zone)

PJM reports that new interconnection requests across its system are dominated by solar (35%), storage (26%), and wind (18%). In Illinois, PJM forecasts summer peak load growth of 1.6% annually and winter peak growth of 2.9% over the next decade. The 2024 RTEP pipeline totals about $1.533 billion in the state’s PJM zone, indicating both rising demand and ongoing network upgrades in northern Illinois.[8]

MISO queue delays

MISO’s interconnection queue is backed up well beyond tariff timelines.

  • The tariff timeline is one year, but cycles are taking 3-4 years because of backlog and restudies. MISO has implemented queue volume caps and expedited resource adequacy studies as stop-gap measures. For Illinois data center projects in the MISO footprint, queue duration is a core bottleneck to new generation and large-load interconnections.[11]

What to Watch

  • MISO Tranche 2.1 regulatory approvals: The $21.8 billion transmission portfolio must clear state-level regulatory approvals and siting processes over the next several years before construction begins.
  • Lincoln Land Energy Center construction timeline: EmberClear has not announced a final in-service date for the 1,100 MW gas plant. If the project proceeds, it will be a major new firm-power source for large loads.
  • Vistra’s 833 MW solar + storage portfolio: The two-year extension requested in 2025 pushes project timelines into 2027 or later. Watch for updated interconnection milestones and equipment delivery schedules.

Sources

[1] Power Magazine, “Illinois EPA Issues Permit for New 1.1-GW Gas-Fired Facility,” August 8, 2022, https://www.powermag.com/illinois-epa-issues-permit-for-new-1-1-gw-gas-fired-facility/ (accessed January 8, 2026).

[2] Constellation Energy, “Constellation, Meta Sign 20-Year Deal for Clean, Reliable Nuclear Energy in Illinois,” June 3, 2025, https://www.constellationenergy.com/newsroom/2025/constellation-meta-sign-20-year-deal-for-clean-reliable-nuclear-energy-in-illinois.html (accessed January 8, 2026).

[3] Vistra, “Construction Update 1: Pulaski Solar To Be Online By 2026” (PDF), August 5, 2024, https://renewillinoispower.com/wp-content/uploads/2024/08/Pulaski_Construction_Update_August_5_compressed-4.pdf (accessed January 8, 2026).

[4] RWE, “RWE begins onsite construction on its first utility-scale solar project in Illinois to support rapidly growing demand for clean power,” June 10, 2024, https://americas.rwe.com/press/2024-06-10-rwe-begins-onsite-construction-on-its-first-utility-scale-solar-project/ (accessed January 8, 2026).

[5] Energy Global, “Avangrid announces fifth wind farm in Illinois,” March 12, 2024, https://www.energyglobal.com/wind/12032024/avangrid-announces-fifth-wind-farm-in-illinois/ (accessed January 8, 2026).

[6] Midcontinent Independent System Operator (MISO), “Long Range Transmission Planning (LRTP),” page updated 2024, https://www.misoenergy.org/planning/long-range-transmission-planning/ (accessed January 8, 2026).

[7] Utility Dive, “SOO Green underground transmission line between MISO, PJM clears key hurdle with Iowa approval,” September 18, 2023, https://www.utilitydive.com/news/soo-green-transmission-miso-pjm-interregional-big-wires-act-hickenlooper/693916/ (accessed January 8, 2026).

[8] PJM Interconnection, “2024 Illinois State Infrastructure Report (January 1, 2024 - December 31, 2024),” June 2025, https://www.pjm.com/-/media/Library/reports-notices/state-specific-reports/2024/illinois.pdf (accessed January 8, 2026).

[9] BayWa r.e. Americas, “Little Prairie Hybrid Project,” page updated January 8, 2026, https://us.baywa-re.com/en/projects/local-projects/little-prairie-hybrid (accessed January 8, 2026).

[10] Utility Dive, “Vistra solar, battery projects in MISO face supply chain delays,” May 28, 2025, https://www.utilitydive.com/news/vistra-solar-battery-illinois-miso-ferc-waiver-supply-chain/749098/ (accessed January 8, 2026).

[11] Midcontinent Independent System Operator (MISO), “Generator Interconnection Queue Update,” System Planning Committee of the Board of Directors, December 10, 2024 (PDF), https://cdn.misoenergy.org/20241210%20System%20Planning%20Committee%20of%20the%20BOD%20Item%2004%20Generator%20Interconnection%20Queue%20Update665714.pdf (accessed January 8, 2026).