Neptune Gas Processing Plant
Other fuels power plant in St Mary Parish, Louisiana. 4.5 MW of nameplate capacity across 1 generator, operated by Enterprise Products Optg LP.
Also known as EIA plant 56139
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 4.5 MWNameplate
- Generators
- 1 operatingEIA-860M, August 2026
- Operating since
- February 2004First generator online
- Operator
- Enterprise Products Optg LPEIA operator ID 29925
- Grid
- MISOBalancing authority MISO
- Price nodes
- None linkedNo verified ISO node
- Location
- St Mary Parish, LA29.7336, −91.4431
- EIA plant ID
- 56139EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Neptune Gas Processing Plant produces
Free · EIA-923Net generation, 2025
14.1 GWh
14,102 MWh, final
Capacity factor, 2025
35.8%
2024: 30.6%
January to July 2026
Not reported
Provisional. 0 of 7 months reported
Range, 2015 to 2025
10.3–19.6
GWh a year. Low 2022, high 2016
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | Not reported | Not reported | 0 of 12 |
| 2002 | Not reported | Not reported | 0 of 12 |
| 2003 | Not reported | Not reported | 0 of 12 |
| 2004 | 7,950 | Not reported | 12 of 12 |
| 2005 | 8,959 | Not reported | 12 of 12 |
| 2006 | Not reported | Not reported | 0 of 12 |
| 2007 | 12,765 | Not reported | 12 of 12 |
| 2008 | 6,983 | Not reported | 12 of 12 |
| 2009 | 6,655 | Not reported | 12 of 12 |
| 2010 | 10,454 | 26.5% | 12 of 12 |
| 2011 | 13,150 | 33.4% | 12 of 12 |
| 2012 | 18,801 | 47.6% | 12 of 12 |
| 2013 | 16,403 | Not reported | 12 of 12 |
| 2014 | 9,225 | 23.4% | 12 of 12 |
| 2015 | 18,919 | 48.0% | 12 of 12 |
| 2016 | 19,597 | 49.6% | 12 of 12 |
| 2017 | 14,667 | 37.2% | 12 of 12 |
| 2018 | 16,106 | 40.9% | 12 of 12 |
| 2019 | 14,077 | 35.7% | 12 of 12 |
| 2020 | 12,917 | 32.7% | 12 of 12 |
| 2021 | 14,348 | 36.4% | 12 of 12 |
| 2022 | 10,256 | 26.0% | 12 of 12 |
| 2023 | 11,286 | 28.6% | 12 of 12 |
| 2024 | 12,110 | 30.6% | 12 of 12 |
| 2025 | 14,102 | 35.8% | 12 of 12 |
| 2026 (provisional, partial year) | Not reported | Not reported | 0 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free accountNo verified ISO price node is linked to this plant, or its price history could not load.
Emissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo EIA cooling-water record for this plant in 2024.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| NPCG | All Other | 4.5 | February 2004 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists Enterprise Products Optg LP as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
Generation potential vs reported
Monthly potential at seasonal net capability, next to EIA-923 output. Shows how much of the plant's capability was used.
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Power plants near Neptune Gas Processing Plant
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Questions about Neptune Gas Processing Plant
How much power does Neptune Gas Processing Plant produce?
Neptune Gas Processing Plant reported 14,102 MWh (14.1 GWh) of net generation in 2025, a 35.8% capacity factor on 4.5 MW of nameplate capacity.
Where is Neptune Gas Processing Plant?
Neptune Gas Processing Plant is in St Mary Parish, Louisiana, at 29.7336, −91.4431. It is in the Midcontinent Independent Transmission System Operator, Inc.. balancing area (MISO).
Who operates Neptune Gas Processing Plant?
EIA-860M for August 2026 lists Enterprise Products Optg LP as the operator (EIA operator ID 29925). The operator is not always the owner.
When did Neptune Gas Processing Plant start operating?
Its first generator began operating in February 2004, according to EIA-860M.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page