Search
Search plants, projects, owners, and states
Search plants, projects, owners, and states
249 MW Conventional Steam Coal (99 MW) + Natural Gas Fired Combustion Turbine (150 MW) operating in Williamson, IL
249 MW
Nameplate Capacity
5
Generators
units
Hybrid (2)
Technology
Conventional Steam Coal + Natural Gas Fired Combustion Turbine
1963
Operating Since
Coordinates
37.6176, -88.9569
County
Williamson, IL
Nearby Plants
Forward-looking, asset-specific exposure analytics combining climate hazards, generation variability, and counterparty risk into a single decision-grade view. Powered by InfraRisk.
See the full risk decomposition + scenarios for this asset.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Southern Illinois Power Coop | — | — |
| Owner(s) | Southern Illinois Power Coop | — | — |
| Status | Operating | — | — |
The Marion power plant, located in Williamson County, Illinois, has a total capacity of 249 MW. The plant began operating in 1963 and is owned and operated by Southern Illinois Power Coop. The primary fuel source is bituminous coal (BIT), and the plant utilizes conventional steam coal technology, along with natural gas fired combustion turbine technology, classifying it as a hybrid plant. Marion consists of 5 generators.
In the most recent year with available data, the plant generated 767,048 MWh, operating at a capacity factor of 35.2%. Marion operates within the Midcontinent Independent Transmission System Operator, Inc. (MISO) balancing authority and the SERC NERC region. The plant is ranked 3 out of 4 among similar plants in Illinois and 46 out of 50 nationally.
Generated from EIA, GEM, and public data sources
ISO/RTO
MISO
Market
ISO/RTO Member
NERC Region
SERC — SERC Reliability Corporation
Balancing Authority
Midcontinent Independent Transmission System Operator, Inc.. (MISO)
Grid Voltage
161.0 kV
Regulatory Status
RE — Regulated
Entity Type
Cooperative
Sector
Electric Utility
Monthly net generation as reported to EIA-923 — useful for historical context. Confidence varies sharply by fuel type; the band above and the “About this data” button explain the caveats specific to this plant and how InfraSure’s in-house model handles them.
74.0K MWh
Latest Month
767.0K MWh
Annual Generation
35.2%
Capacity Factor
Forward-looking generation outlook with probabilistic ranges across weather, demand, and policy scenarios. Powered by InfraSure's generation modeling stack.
See the full forecast + scenario decomposition for this asset.
CO₂ Intensity
3232 lb/MWh
NOx
1 lb/MWh
SO₂
7 lb/MWh
CH₄
0.343 lb/MWh
N₂O
0.050 lb/MWh
Capacity Factor
32.5%
Annual Net Gen
709 GWh
CO₂eq
3255 lb/MWh
Subregion
SERC Midwest
No financial data available for this plant.
This is the open data foundation underneath InfraSure's analytical layer — if you have sources or want more coverage here, drop a note.
Forward revenue, DSCR bands, and refinancing risk projected under price, demand, and policy scenarios. Powered by InfraSure's asset cashflow stack.
See the full revenue + DSCR projection for this asset.
Market Position
ISO/RTO Market
MISO
LMP Node
SIPC.MARIOGEN5
Pricing Hub
ILLINOIS.HUB
Location Type
Generation Node
Node Source
EIA-860 direct report
No wholesale contracts disclosed in FERC EQR for this plant.
FERC EQR captures bilateral wholesale energy + capacity contracts ≥$1M/yr filed quarterly by jurisdictional sellers — covers renewable PPAs, thermal energy sales agreements, capacity contracts, and tolling agreements alike. Many plants don't appear: regulated-utility output flows to ratepayers via cost-of-service rather than bilateral contracts; small projects fall below the filing threshold; tax-equity-financed renewables route offtake to investors not utilities; merchant plants sell into ISO clearing markets without bilateral contracts. News-extracted buyer facts (below) may surface contracts disclosed only through announcements.
Last updated 2026-03-26
View all articlesNo Ask reports yet for this entity.
Ask about MarionForward forecasts, scenario decomposition, and risk-decision tooling for this asset.