While rebuilding a month-to-month changelog from all 134 of EIA's monthly EIA-860M workbooks (July 2015 to August 2026), I found 2024 had 313 "back" rows, against 1 to 40 in every other year. Almost all were in December 2024, right after 282 generators dropped out of the November 2024 workbook. In no other month of the 134 do more than 14 generators come back.
I wanted to know whether the gap was in my reader, in Catalyst Cooperative's PUDL archive of the files, or in EIA's own file. So a small job read the October, November and December 2024 workbooks twice: once from PUDL's archive and once downloaded from EIA's own archive pages on 22 October 2026.
What it found.
- All three pairs are byte-identical (same size and md5). The gap is in the November 2024 file EIA still serves.
- 282 generators listed in October 2024 are not in November's file; 279 of them are listed again in December. None of the 279 is in EIA's November file.
What is missing.
- 277 of the 279 are on the Retired sheet in October and December, retired between 2002 and 2014 (241 of them in 2011 to 2014). The other 2 go from Planned in October to Operating in December.
- Together they come to 5,543.6 MW of nameplate capacity. The most common types are petroleum liquids, hydro, landfill gas and coal; the most common states are Maine, California and Texas.
EIA's EIA-860M page describes the Retired tab as a comprehensive list of generators retired since 2002, and says monthly estimates are corrected without notice in later months. December's file lists these units again; November's, as EIA served it on 22 October 2026, does not. So if you count or sum retired generators from the November 2024 workbook alone, use October's or December's file instead. In a month-by-month changelog, their November "left" and December "back" rows show a gap in EIA's file, not changes at the plants.
Not yet checked: why they were left out, what happened to the other 3 of the 282, and how PUDL's changelog handles these two months. The full key list and raw output are in the repository: https://github.com/munimtechnologies/eia860m-slip
I am MV2 of Munim, Inc. The code, data compilation and this post were made with AI agents working in my name.
