core_ferc1__yearly_depreciation_factors_sched336
Return to SearchAnnual time series of factors used in estimating depreciation charges.
- Most-recent data:
2024
- 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 336 - Section C)
- Primary key:
This table has no primary key. This table is too unstructured to have a primary key.
Usage Warnings
Some columns contain subtotals; use caution when choosing columns to aggregate.
Contains columns which may appear categorical, but are actually free text.
The rate and percentage (pct) columns are reported either as values between 0-1 or 0-100. It is often consistent within a given utility-year but use caution when comparing value across different utilities and even the same utility filing in a different year.
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
This table contains details at a variety of levels of granularity.There are many free-form text fields in this table which results in respondents filling out this table very differently from each other or from year to year. We recommend using this table carefully with one utility-year at a time - not attempting to perform analysis across long time-series or across utilities without much caution and cleaning. This table only contains information from Section C: Factors Used in Estimating Depreciation Charges.
Columns
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.
Four-digit year in which the data was reported.
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.
Label of the factor of depreciation factors. This field contains is an unstructured, free-form strings. It often includes FERC account IDs, sometimes includes plant names and sometimes includes headers indicating the beginning of a new section - such as a plant or asset type header which is followed by sub-components like FERC account IDs or plant names depending on the section.
Depreciable plant balance (depreciable base) to which rates are applied.
Percentage representing the estimated value of utility plant at the end of its service life. Be aware that the formatting of this column is not expected to be standard - expect some values between 0-1 and some between 0-100.
Depreciation rate applied to utility plant balance.Be aware that the formatting of this column is not expected to be standard - expect some values between 0-1 and some between 0-100.
Description of the type of mortality curve selected in plant mortality studies prepared to assist in estimating average service lives.
This field is defined in FERC-XBRL documentation as a field that is used to sequence a table.FERC-XBRL documentation notes: 'This field is added to a table to control ordering of the items on the table.'FERC's documentation also notes that this field should always be an integer - although there are many instances of floating point values which seem to increment by decimal points. Nonetheless, this field can be used to help understand the original order of the table. This field did not exist prior to FERC publishing Form 1 as XBRL and thus is always null prior to 2021.
Account number(s) in connection with factors used in estimating depreciation charges.
Estimated average service life of utility plant. The original DBF data was reported as years while the XBRL data was reported as strings in this time duration format: PnYnMnDTnHnMnS. PUDL converts these string time durations into years.
Estimated weighted average of remaining life of utility plant assets.The original DBF data was reported as years while the XBRL data was reported as strings in this time duration format: PnYnMnDTnHnMnS. PUDL converts these string time durations into years.