[WesIngwersen]

Implements the split in #902, which stays open as the plan. Stacked on #1220.

Adds bedrock/transform/eeio/electricity_delivery.py, which splits each buyer's electricity bill into generation and a delivery margin. It also changes generation_price from #1220 to a three-year trailing average. Nothing in the model reads the split yet, so no output changes. The older G/T/D allocator is untouched, because released configs use it. #1217 wires this in.

The method

kWh_i      = bill_i / price_i, scaled so each class's kWh equals EIA's sales
gen_i      = kWh_i x p_gen, and never more than the bill
delivery_i = bill_i - gen_i

• Generation price: EIA-861 sales for resale, pooled over three years ending in that year.
• Floor: a buyer still below it has generation held at its bill and no delivery margin, and is flagged floored.
• Classes: only rail and transit stay in EIA's transportation class. Trucking, warehousing and the rest of NAICS 48-49 move to commercial, because the older mapping put $14bn of bills on 7 TWh.
• Exports: take EIA Table 2.14 kWh.
• Electric power's own purchases: aren't end use, so they stay in generation.
• Line losses: generation less end use and exports, returned separately for Split electric power into 221100 generation and 42ELEC delivery, with emissions and margins #1217 to enter as an input to 42ELEC. Buyer kWh are on EIA's delivered basis, no longer scaled to eGRID.

Why three years, trailing

Manufacturing industries priced below each candidate, on #1219's prices before bills are applied:

	2017	2018	2019	2020	2021	2022	2023	2024
Annual	1	1	0	0	6	4	1	0
3-year trailing (used)	2	1	0	0	0	0	2	1
3-year centered	1	1	0	0	3	1	1	not available
5-year trailing	4	3	1	0	0	0	0	0

Centered needs 2025 revenue, which the source doesn't have yet. Trailing also matches why the spike doesn't reach these buyers at once: retail rates lag wholesale.

Results on the real bills, MUT v1.0.0_b17908f

$bn unless stated	2017	2018	2019	2020	2021	2022	2023	2024
Generation price, ¢/kWh	4.59	4.28	4.23	4.14	4.56	5.24	5.76	5.55
Bills	457	476	471	461	497	566	569	589
Generation sold to buyers	171	166	162	154	174	207	224	221
Delivery (42ELEC sales)	275	298	298	296	307	343	332	355
Own purchases	11	12	12	11	16	17	13	12
Line losses, TWh	165	151	166	151	162	157	160	183
Line losses	7.6	6.5	7.0	6.3	7.4	8.3	9.2	10.1
Buyers floored	2	0	0	2	0	0	0	0

• Floor: only rail and transit, in 2017 and 2020, at most $0.07bn. No manufacturer is floored in any year, because bills run above EIA.
• Delivered kWh: class kWh match EIA's sales by construction.

By class, 2024:

	Bill, ¢/kWh	EIA, ¢/kWh	Margin, ¢/kWh	Delivery, share of bill
Residential	16.70	16.48	11.15	67%
Commercial	15.43	12.75	9.88	64%
Industrial	10.02	8.13	4.48	45%

Inside manufacturing, 2024: margins run from 0.89 ¢/kWh (wet corn milling) and 1.59 (steel) to 8.38 (beverages) and 11.54 (asphalt paving), with a median of 6.27.

Estimated effect on N, 2024

An estimate rather than a built model: generation emissions follow generation dollars, and losses and the non-fuel chain follow delivery dollars, applied through today's L. #1217 replaces it.

Median change, all sectors	+4.6%
Median by class	industrial +6.9%, commercial +0.5%, rail and transit +1.3%
Sectors above 10% / 20%	41 / 2
Largest moves	331200 steel products +22%, 331410 nonferrous smelting +22%, S00102 -7%
Emissions moved	households -79 Mt, commercial -33 Mt, industrial +109 Mt
N of 42ELEC	0.28 kg per dollar
N of generation	6.45 kg per dollar

Limits

• Bills stay above EIA: commercial about 1.21× and industrial about 1.23× revenue in 2024. The excess lands in delivery, so it no longer raises emissions but does overstate margins.
• Rail and transit bills are low against EIA (3.7-11.1 ¢/kWh against about 10-13). They are small, under $1bn.
• Own purchases staying in generation is a simplification for Split electric power into 221100 generation and 42ELEC delivery, with emissions and margins #1217 to review.

Checks

Unit tests are synthetic and need no data. black, ruff and mypy are clean on these files. The real-data results above came from a local run. The suite is left to CI.

🤖 Generated with Claude Code