core_ferc1__yearly_transmission_lines_sched422

package: pudl

Annual time series of statistics about transmission lines.

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 422)

Primary key:

This table has no primary key. Each record of this table is supposed to represent one stretch of a transmission line, but there are no IDs and many nulls in the fields which would nominally distinguish unique transmission lines.

Usage Warnings

  • Contains columns which may appear categorical, but are actually free text.

  • Some columns contain subtotals; use caution when choosing columns to aggregate.

  • 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

Information describing transmission lines, the cost of lines, annual operating and capital expenses, etc. This table includes transmission lines having nominal voltage of 132 kilovolts or greater. Transmission lines below these voltages are required to be reported in group totals only for each voltage.

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.

start_point

The starting point of a transmission line.

end_point

The end point of a transmission line.

operating_voltage_kv

The operating voltage, expressed kilo-volts, for three-phase 60 cycle alternative current transmission lines.

designed_voltage_kv

Manufactured (Designed) voltage, expressed in kilo-volts, for three-phase 60 cycle alternative current transmission lines

supporting_structure_type

Supporting structure of the transmission line.

transmission_line_length_miles

Length (in pole miles or circuit miles (if transmission lines are underground)) for lines that are stand alone structures (whose cost are reported on a stand-alone basis).

transmission_line_and_structures_length_miles

Length (in pole miles or circuit miles (if transmission lines are underground)) for lines that are agrregated with other lines / structures (whose cost are aggregated and combined with other structures).

num_transmission_circuits

Number of circuits in a transmission line.

conductor_size_and_material

Size of transmission conductor and material of the transmission line.

capex_land

Cost of Land and land rights for the transmission line.

capex_other

Construction and other costs for the transmission line.

capex_total

Total costs for the transmission line.

opex_operations

Operating expenses for the transmission line.

opex_maintenance

Maintenance expenses for the transmission line.

opex_rents

Rent expenses for the transmission line.

opex_total

Overall expenses for the transmission line.