Rosebud County, MT. Reports to the NorthWestern Energy balancing authorityThe organization that balances electricity supply and demand in a reporting area.Definition ↗.
Nameplate capacity, operating generatorsFull nameplate rating of the operating generators, before ownership shares. MW measures rated power; annual output is energy in MWh.Definition ↗
1,647.4MW
Source & method
Sum of generator nameplate MW with operational status code OP in the inventory year; one row per generator; unscaled by ownership
2024 inventory · reported · derived · valid · final
Net generationEnergy produced over the stated period after the plant’s own use, including signed storage output. Plant output is not allocated to owners or buyers.Definition ↗
9,028,457MWh
2024
Source & method
Sum of EIA-923 annual net generation over the plant's unique prime-mover x energy-source rows; negative values (pumping, station use) retained
2024 calendar year · reported · derived · valid · final
Net generation MWh / (operating nameplate MW x hours in year); only when every operating generator was operating before the year began and none retired during it
2024 calendar year · reported · derived · valid · final
derived: net_generation_mwh@2024 / (nameplate_mw_op x 8784 h)
Ownership basisHow a generator's owners were established: from EIA-860's ownership schedule (reported), from EIA's rule that a unit absent from a complete schedule is wholly owned by its operator (derived), or unknown.Definition ↗
OwnerAn organization with a reported share of a generator. Owned MW applies that share to operating nameplate capacity; it does not establish who buys the output.Definition ↗Investor-owned utilityPuget Sound Energy ↗
411.9MW owned
OwnerAn organization with a reported share of a generator. Owned MW applies that share to operating nameplate capacity; it does not establish who buys the output.Definition ↗Investor-owned utilityPortland General Electric ↗
329.5MW owned
OwnerAn organization with a reported share of a generator. Owned MW applies that share to operating nameplate capacity; it does not establish who buys the output.Definition ↗Independent power producerTalen Montana ↗
247.1MW owned
OwnerAn organization with a reported share of a generator. Owned MW applies that share to operating nameplate capacity; it does not establish who buys the output.Definition ↗Investor-owned utilityAvista ↗
247.1MW owned
OwnerAn organization with a reported share of a generator. Owned MW applies that share to operating nameplate capacity; it does not establish who buys the output.Definition ↗Investor-owned utilityNorthWestern Energy ↗
247.1MW owned
OwnerAn organization with a reported share of a generator. Owned MW applies that share to operating nameplate capacity; it does not establish who buys the output.Definition ↗Investor-owned utilityPacifiCorp ↗
164.7MW owned
Operating nameplate MW x ownership fraction, once per generator; reported schedule or EIA-860 schedule-4 default. Ownership source & rules ↗
Generators at this plant
Unscaled nameplateA generator’s rated maximum power, in MW. Capacity is a rating, not how much electricity it produced.Definition ↗
4 generators, including non-operating units where reported. Status is the inventory-year status.
Generator
Technology / statusWhether a generator or project is operating, planned, on standby or retired, as its source reports it.Definition ↗
NameplateA generator’s rated maximum power, in MW. Capacity is a rating, not how much electricity it produced.Definition ↗ · MW
Ownership basisHow a generator's owners were established: from EIA-860's ownership schedule (reported), from EIA's rule that a unit absent from a complete schedule is wholly owned by its operator (derived), or unknown.Definition ↗
Physical capacity once (operating nameplate MW); each direct owner's share and owned MW on its existing basis; up each curated chain, exposure = MW below x the stated hop share, so it exists only while every hop is stated. MW stays at the last stated entity where a filing states control without a share. Direct MW and parent MW are two views of the same capacity and are never added together.
Capacity 1,647.4 MW operating, counted once. A parent's exposure is its share of the same MW its subsidiary owns, not additional MW.
Top of each chain
Reached through
Exposure (MW)
Puget Holdings LLC (outside this sample)share not stated
NorthWestern Energy Group, Inc. (outside this sample)publicly held
NorthWestern Energy
247.1 MW
Berkshire Hathaway Inc. (outside this sample)publicly held
PacifiCorp
164.7 MW
Not attributable to any named entityOperating nameplate MW minus the exposure reaching every terminal entity of the curated chains: direct capacity with no established owner, unassigned direct fractions, and remainders where stated parent shares sum below one with no holder named
0 MW
Every hop, generator by generator
Generator 3 · 823.7 MW · shares on the reported schedule basis
Puget Energy, Inc. wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
Puget Equico LLC wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
Puget Intermediate Holdings Inc. wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
Puget Holdings LLC wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
British Columbia Investment Management Corporation fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Alberta Investment Management Corporation fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Ontario Municipal Employees Retirement System fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
PGGM Vermogensbeheer B.V. fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Macquarie Washington Clean Energy Investment, L.P. fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Ontario Teachers' Pension Plan Board fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Puget Energy, Inc. wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
Puget Equico LLC wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
Puget Intermediate Holdings Inc. wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
Puget Holdings LLC wholly owned subsidiary · 100.0% → 205.93 MW· as of 2026-02-19 · source ↗
British Columbia Investment Management Corporation fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Alberta Investment Management Corporation fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Ontario Municipal Employees Retirement System fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
PGGM Vermogensbeheer B.V. fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Macquarie Washington Clean Energy Investment, L.P. fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Ontario Teachers' Pension Plan Board fund managed · share not stated (share not stated in source) → not attributed· as of 2025-12-31 · source ↗
Announced changes after the inventory, listed and not applied: Share is the seller's stated interest in each unit (Avista FY2025 10-K, Item 7: "We previously held a 15 percent interest in Units 3 and 4 of Colstrip"; "On January 1, 2026, the Company transferred its ownership in Colstrip to NorthWestern"). The 222 MW is NorthWestern's figure, on its own capacity basis, not the release's nameplate. Exhibit 21 lists a NorthWestern Colstrip 222Av LLC without stating what it holds, so the acquirer is recorded as the group ("we"); Share is the seller's interest in each unit as EIA-860 2024 reports it (25 percent of Units 3 and 4) and as NorthWestern states for NW Colstrip 370. The 370 MW is NorthWestern's figure on its own capacity basis. Consideration "$0" as stated. NW Colstrip 370 is a direct, wholly-owned subsidiary of NorthWestern Energy Group (org:sec:1993004).
Operator: Talen Montana. Owners: Puget Sound Energy, Portland General Electric, NorthWestern Energy, Talen Montana, Avista, PacifiCorp. Who sells the output to customers: Who sells this plant's output to customers is a supply relationship (a contract, a portfolio claim or a disclosure), not an ownership share; an owner may sell its share wholesale, and a utility may serve customers from plants it does not own. Filed claims on this plant's output, where Washington's fuel-mix disclosure has any, appear in their own section.
Direct owners of the operating units in the 2024 inventory (EIA-860 Schedule 4): Talen Montana (30 percent of Unit 3), Puget Sound Energy (25 percent of Units 3 and 4), Portland General Electric (20 percent of both), Avista (15 percent of both), PacifiCorp (10 percent of both), NorthWestern Energy (30 percent of Unit 4). Each owner's FY2025 Form 10-K states the same interest (PGE 20 percent of Units 3 and 4; Talen Montana 30 percent of Unit 3; Avista 15 percent of Units 3 and 4 until 2026-01-01). Units 1 and 2 are retired (January 2020) and carry no operating MW. Talen Montana operates the plant; the operator role is not an ownership share Curation and sources
CO2 filed by EPA-monitored unitsAn EPA emissions unit (a combustor or stack) with CEMS rows in the year, linked to EIA generators through the EPA-EIA crosswalk. A plant is fully monitored when every existing coal, gas, oil or waste generator is linked to one; otherwise its monitored CO2 is shown but never as the plant's total.Definition ↗
2024 · estimated
2 monitored units covering 2 of 2 combustion generators, 1,647.4 of 1,647.4 MW. 98.4% of operating unit-hours carry EPA’s measured flag; the rest are substitute dataHours a unit filled under Part 75 missing-data procedures instead of a monitor reading; EPA flags each hour Measured, Substitute or Measured and Substitute. Substitute values are designed to err high. The atlas counts these hours, and a plant's CO2 fact is metered only when at least 99 percent of its operating unit-hours were measured.Definition ↗.
CO2 mass, monitored units
9,099,950t CO2
2024·estimated
Source & method
Sum of hourly CO2 mass reported under 40 CFR Part 75 by the plant's EPA-monitored units over the reporting year, short tons x 0.90718474. Stack total of those units including any share attributable to steam sold; the plant's total only where every combustion generator is monitored
2024 calendar year · estimated · derived · valid · final
2 of 2 combustion generators included.
98.4% of operating unit-hours were flagged Measured; the rest follow Part 75 missing-data procedures, which are designed to err high
Monitored-unit CO2 (tonnes) divided by the plant's EIA-923 net generation for the same year. Only where every combustion generator is monitored, so numerator and denominator cover the same plant; comparable across such plants
2024 calendar year · estimated · derived · valid · final
Monitored-unit CO2 (tonnes) divided by the same units' reported gross load. Only where every combustion generator is monitored and the gross load is not below EIA net generation; gross, so lower than the net figure, and not comparable with it
2024 calendar year · estimated · derived · valid · final
Each reporting year as filed and set against that year’s own generator inventory. Years sit side by side; no change between them is computed, because the monitored units can differ.
Year
CO2t CO2
Evidence
Measured shareof operating unit-hours
Net intensityt CO2/MWh
2023
10,879,333
estimated2 units, 2 of 2 generators
98.6%
1.005
2024
9,099,950
estimated2 units, 2 of 2 generators
98.4%
1.008
Every figure filed
Figure
Value
Basis
CO2 mass, monitored units
9,099,950 t CO2
Sum of hourly CO2 mass reported under 40 CFR Part 75 by the plant's EPA-monitored units over the reporting year, short tons x 0.90718474. Stack total of those units including any share attributable to steam sold; the plant's total only where every combustion generator is monitored
CO2 mass, monitored units, as filed
10,030,977 short tons CO2
The same sum in the unit EPA's files use (short tons); shown beside the metric figure so the conversion is visible
Gross load of monitored units
9,961,335 MWh
Sum over the year of each monitored unit's reported hourly gross load (MW) x operating time (h). A unit-reported quantity: a combined-cycle unit need not include its steam turbine, so this can be below EIA net generation
Heat input of monitored units
95,681,310 mmBtu
Sum over the year of each monitored unit's reported hourly heat input
Unit operating hours, monitored units
14,298.8 h
Sum of reported operating time over the plant's monitored units: unit-hours, so it can exceed the hours in the year when several units ran
Hours in which a monitored unit ran
8,306 count
Calendar hours of the reporting year in which at least one monitored unit reported operating time; never above the hours in the year
EPA emissions units with CEMS rows
2 count
Distinct EPA emissions units at the plant with rows in the reporting year; an EPA unit is a combustor or stack, not an EIA generator
Combustion generators linked to a monitored unit
2 count
Existing coal, gas, oil or waste generators of the plant (EIA-860 inventory year) that the EPA-EIA crosswalk links to a unit with CEMS rows; a steam turbine linked to several combustion turbines counts once
Combustion generators at the plant
2 count
Existing (operating, standby or out of service) generators whose resource group is coal, gas, oil or waste in the EIA-860 inventory year: the units that could be monitored
Share of operating unit-hours with measured CO2
0.9841 fraction
Operating unit-hours EPA flagged Measured divided by all operating unit-hours of the plant's monitored units; the rest were Substitute, Measured and Substitute, or another method code
CO2 per MWh of net generation
1.008 t CO2/MWh
Monitored-unit CO2 (tonnes) divided by the plant's EIA-923 net generation for the same year. Only where every combustion generator is monitored, so numerator and denominator cover the same plant; comparable across such plants
CO2 per MWh of gross load (unit-reported)
0.914 t CO2/MWh
Monitored-unit CO2 (tonnes) divided by the same units' reported gross load. Only where every combustion generator is monitored and the gross load is not below EIA net generation; gross, so lower than the net figure, and not comparable with it
CO2 reported hourly under 40 CFR Part 75 by this plant's EPA-monitored units and summed over the reporting year, as filed (short tons) and in tonnes. It is a stack total of those units, includes any share attributable to steam sold, and is not CO2-equivalent, lifecycle or consumption-based. EPA-monitored units are one program's population: the figure is not a regional total and an unmonitored plant is not zero. Evidence rule: metered where at least 99% of the plant's operating unit-hours carry EPA's Measured flag, estimated where more were Substitute, Measured and Substitute or another method code. Source and notice· matched through EPA’s crosswalk.
Latest inventoryThe newest complete monthly inventory, with dated status and capacity changes beside the annual baseline totals.Definition ↗ · August 2026
Operating
No confirmed status or capacity changes among comparable units. Missing monthly assertions and units outside the baseline have no like-for-like comparison.
Operating nameplate capacity, latest inventoryOperating nameplate MW in this monthly inventory. Compare it with the annual baseline; do not add the two inventories together.Definition ↗
1,647.4MW
· provisional
Source & method
Sum of nameplate MW over generators whose current-valid EIA-860M workbook assertion has status OP; dated by the complete inventory edition; never added to the baseline aggregate
Planned nameplate capacity, latest inventoryNameplate MW proposed or under construction in this monthly inventory, separate from operating MW. Planned dates are forecasts.Definition ↗
Not applicable
· provisional
Source & method
Sum of nameplate MW over generators whose current-valid EIA-860M workbook assertion is a proposal or construction stage (P, L, T, U, V, OT, TS); a proposal is not a commitment and its date is a forecast
Retired or cancelled nameplate capacity, latest inventory
716MW
· provisional
Source & method
Sum of nameplate MW over generators whose current-valid EIA-860M workbook assertion is retired, cancelled or indefinitely postponed (RE, CN, IP); retired is not demolished
Each unit's operating span from its reported operating date to its retirement date or to the August 2026 inventory (the vertical line). Dashed spans start at a planned operating date, a forecast; a short bar marks a planned retirement. Standby and out-of-service units are hatched.
Units as a table
Unit lifecycle from EIA-860M, August 2026.
Unit
State
Operating since
Planned
Retired
MW
1
Retired or cancelled
November 1975
—
January 2020
358MW
2
Retired or cancelled
August 1976
—
January 2020
358MW
3
Operating
January 1984
—
—
823.7MW
4
Operating
April 1986
—
—
823.7MW
Independently dated by EIA-860M; the baseline facts above stay the validated edition. Planned dates are forecasts; retired is not demolished.
Washington Fuel Mix Disclosure claims on this plant for CY2024, the latest year loaded; several suppliers can claim one plant; a claim attributes retail sales, it is not a wire or a share of ownership
Approximate service areasAn approximate utility service area. The boundary cannot identify the supplier for a particular address.Definition ↗ containing the plant’s location. A geographic candidate, not a supply relationship.
Within 3 km of the reported plant point, nearest first. BPA’s published lines, HIFLD-compiled lines of other owners and HIFLD 2022 substations; nearness does not establish an electrical connection.
Forms 10-K for fiscal year 2025 of Puget Energy and Puget Sound Energy, Berkshire Hathaway Energy (PacifiCorp), Berkshire Hathaway Inc., NorthWestern Energy Group, Talen Energy Corporation, Portland General Electric and Avista Corporation, as filed with the U.S. Securities and Exchange Commission, and Capital Power Corporation's 2025 Annual Information Form as filed on SEDAR+, each cited on its row
A parent chain is what the owner's own filing states on the cited page, read on the checked date: a share is published only where the filing gives a percentage or says wholly owned, and a filing that states control without a percentage leaves the share null and stops the arithmetic there. Parent-attributed MW is a share of the same physical capacity as the direct owner's MW and is never added to it. Holders above 5 percent of a listed company are in its proxy statement and are not curated. A plant without a reviewed row has no chain, not no parent.
Display names and aliases (pipeline/config/crosswalks/aliases.csv)
Display names verified against each organization's own website; EIA legal names retained as aliases
A display name is the name an organization uses for itself; the EIA name stays searchable and on the record. Each row cites the page that shows the name.
Catalyst Cooperative, PUDL v2026.9.0, derived from U.S. EIA Forms 860/923
Data transformed by PUDL from U.S. EIA forms; selected fields republished; EIA data is public with dated acknowledgment (https://www.eia.gov/about/copyrights_reuse.php)
Catalyst Cooperative, PUDL v2026.9.0, derived from U.S. EIA Forms 860/923
Data transformed by PUDL from U.S. EIA forms; selected fields republished; EIA data is public with dated acknowledgment (https://www.eia.gov/about/copyrights_reuse.php)
Catalyst Cooperative, PUDL v2026.9.0, derived from U.S. EIA Forms 860/923
Data transformed by PUDL from U.S. EIA forms; selected fields republished; EIA data is public with dated acknowledgment (https://www.eia.gov/about/copyrights_reuse.php)
Catalyst Cooperative, PUDL v2026.9.0, derived from U.S. EIA Forms 860/923
Data transformed by PUDL from U.S. EIA forms; selected fields republished; EIA data is public with dated acknowledgment (https://www.eia.gov/about/copyrights_reuse.php)
Catalyst Cooperative, PUDL v2026.9.0, derived from U.S. EPA CAMD Power Sector Emissions Data
Data transformed by PUDL from U.S. EPA Clean Air Markets Division hourly emissions files; selected fields for two reporting years and four states republished; EPA data is public (https://www.epa.gov/power-sector/power-sector-data)