Marion reports 99 MW coal + 150 MW natural gas of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Aug 2026.

What kind of plant is Marion?

Marion is a Conventional Steam Coal, Natural Gas Fired Combustion Turbine facility in Williamson County, IL, participating in the MISO market.

Where is Marion located?

Marion is in Williamson County, IL, inside the MISO balancing area.

Marion is operated by Southern Illinois Power Coop according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.

How much electricity does Marion generate?

Marion reported 795.6 GWh over the twelve months to 2026-07. Figures are net generation as filed to EIA-923.

How does Marion compare to other plants?

By capacity, Marion ranks #148 of 205 operating plants of the same technology nationally. It ranks #7 of 9 in IL.

Marion — 249 MW hybrid plant, Williamson County, IL

Ask the Grid

Ask the Grid/

Create free workspace

Ask the Grid

Ask the Grid/

Create free workspace

Marion — 249 MW hybrid plant, Williamson County, IL · Ask the Grid

Generation and physical site

EIA plant 976 · Inventory for Aug 2026.

Reported operating nameplate by technology

Coal: 99 MW
Natural gas: 150 MW

Operating generators only. Battery power is in MW; stored energy is in MWh. These ratings do not establish a shared export limit.

Generator records (6)

EIA generator status and nameplate capacity for Marion
Generator	Technology	Status	Power (MW)	Energy (MWh)
1	Conventional Steam Coal	Operating	33	Unknown
2	Conventional Steam Coal	Operating	33	Unknown
3	Conventional Steam Coal	Operating	33	Unknown
5	Natural Gas Fired Combustion Turbine	Operating	75	Unknown
6	Natural Gas Fired Combustion Turbine	Operating	75	Unknown
4	Conventional Steam Coal	Retired	173	Unknown

Physical map location · OpenStreetMap: 37.61658, -88.95759
Filed location · EIA: 37.61975, -88.95311

Sources and observation dates

Inventory source: EIA-860M workbook (preliminary)
EIA reporting month: Aug 2026
EIA retrieved: Oct 10, 2026
OSM extract: Oct 8, 2026
OSM last mapped edit: Aug 1, 2022
Map prepared: Oct 10, 2026
Field verification: Not reported

Reporting month describes the inventory. Retrieval and map preparation describe processing; an OSM edit does not establish an in-service date.

EIA source inventory

Units and generators

Operating generator records and technology attributes reported through EIA-860.

Generator	Capacity	Technology	Operation	Status
1	33 MW 40 MW summer	Conventional Steam Coal Bituminous Coal · ST	Jun 1963	Operating
2	33 MW 40 MW summer	Conventional Steam Coal Bituminous Coal · ST	Aug 1963	Operating
3	33 MW 40 MW summer	Conventional Steam Coal Bituminous Coal · ST	Sep 1963	Operating
4	173 MW 170 MW summer	Conventional Steam Coal Bituminous Coal · ST	Oct 1978 Retirement: Nov 2020	Operating
5	75 MW 70 MW summer	Natural Gas Fired Combustion Turbine Natural Gas · GT	May 2003	Operating
6	75 MW 70 MW summer	Natural Gas Fired Combustion Turbine Natural Gas · GT	May 2003	Operating

Marion

Overview

Infrastructure record

Marion

Overview

Infrastructure record

Explore related directories

Structured profile

Generation and physical site

Reported operating nameplate by technology

Related assets

ArcelorMittal Burns Harbor

Gary Works

Edwardsport

Air Products Port Arthur

Granite City Works

PPG Riverside

Units and generators

Performance

Peer context

Monthly generation

Grid and market context

Nearby substations

Commercial, land, and environmental record

Related parties and identifiers

Relationship graph

Parties and identifiers

Reporting portfolio

Timeline and sources

Project timeline

Sources

Common questions about Marion

How big is Marion?