core_ferc1__yearly_hydroelectric_plants_sched406

package: pudl

Annual time series of plant statistics for large hydroelectric generating plants.

Most-recent data:

2025

Processing:

Data has been cleaned and organized into well-modeled tables that serve as building blocks for downstream wide tables and analyses.

Source:

FERC Form 1 -- Annual Report of Major Electric Utilities (Schedule 406)

Primary key:

This table has no primary key. The best approximation for primary keys for this table would be: report_year, utility_id_ferc1, plant_name_ferc1. FERC does not publish plant IDs. The main identifying column is plant_name_ferc1 but that is a free-form string field and there are duplicate records.

Usage Warnings

  • The plant_type and construction_type are standardized into categorical values from free-form strings.

  • FERC does not restrict respondents to report unique and non-duplicative plant records. There are sporadic instances of respondents reporting portions of plants and then the total plant (ex: unit 1, unit 2 and total). Use caution when aggregating.

  • FERC data is notoriously difficult to extract cleanly, and often contains free-form strings, non-labeled total rows and lack of IDs. See Notable Irregularities for details.

Additional Details

Large plants have an installed nameplate capacity of more than 10 MW.

Columns
record_id

Identifier indicating original FERC Form 1 source record. format: {table_name}_{report_year}_{report_prd}_{respondent_id}_{spplmnt_num}_{row_number}. Unique within FERC Form 1 DB tables which are not row-mapped.

utility_id_ferc1

PUDL-assigned utility ID, identifying a FERC1 utility. This is an auto-incremented ID and is not expected to be stable from year to year.

report_year

Four-digit year in which the data was reported.

plant_name_ferc1

Name of the plant, as reported to FERC. This is a freeform string, not guaranteed to be consistent across references to the same plant.

project_num

FERC Licensed Project Number.

plant_type

Type of plant.

construction_type

Type of plant construction ('outdoor', 'semioutdoor', or 'conventional'). Categorized by PUDL based on our best guess of intended value in FERC1 freeform strings.

construction_year

Year the plant's oldest still operational unit was built.

installation_year

Year the plant's most recently built unit was installed.

capacity_mw

Total installed (nameplate) capacity, in megawatts.

peak_demand_mw

Net peak demand for 60 minutes. Note: in some cases peak demand for other time periods may have been reported instead, if hourly peak demand was unavailable.

plant_hours_connected_while_generating

Hours the plant was connected to load while generating in the report year.

net_capacity_favorable_conditions_mw

Net plant capability under the most favorable operating conditions, in megawatts.

net_capacity_adverse_conditions_mw

Net plant capability under the least favorable operating conditions, in megawatts.

avg_num_employees

The average number of employees assigned to each plant.

net_generation_mwh

Net electricity generation for the specified period in megawatt-hours (MWh).

capex_land

Cost of plant: land and land rights (USD).

capex_structures

Cost of plant: structures and improvements (USD).

capex_facilities

Cost of plant: reservoirs, dams, and waterways (USD).

capex_equipment

Cost of plant: equipment (USD).

capex_roads

Cost of plant: roads, railroads, and bridges (USD).

asset_retirement_cost

Asset retirement cost (USD).

capex_total

Total cost of plant (USD).

capex_per_mw

Cost of plant per megawatt of installed (nameplate) capacity. Nominal USD.

opex_operations

Production expenses: operations, supervision, and engineering (USD).

opex_water_for_power

Production expenses: water for power (USD).

opex_hydraulic

Production expenses: hydraulic expenses (USD).

opex_electric

Production expenses: electric expenses (USD).

opex_generation_misc

Production expenses: miscellaneous power generation expenses (USD).

opex_rents

Production expenses: rents (USD).

opex_engineering

Production expenses: maintenance, supervision, and engineering (USD).

opex_structures

Production expenses: maintenance of structures (USD).

opex_dams

Production expenses: maintenance of reservoirs, dams, and waterways (USD).

opex_plant

Production expenses: maintenance of electric plant (USD).

opex_misc_plant

Production expenses: maintenance of miscellaneous hydraulic plant (USD).

opex_total

Total production expenses, excluding fuel (USD).

opex_per_mwh

Total production expenses (USD per MWh generated).