Create Utility-State pairs in the US

Overview and Purpose

The EIA Form 861 collects annual data on electric power industry participants, including utilities' operations, sales, and characteristics. We use it to create unique utility-state pairs by focusing on active service areas—defined as states where a utility reports positive retail sales (MWh) or customers. This avoids including inactive or headquarters-only states, aligning with SSS requirements for traceable financial relationships (e.g., regulated cost recovery tied to load-serving).

Pairs are generated at the utility_number + state level, prioritized by sales volume for SSS calcs (e.g., filtering for investor-owned or municipal with RPS mandates). For multi-state utilities like Duke Energy, this yields separate pairs (e.g., Duke-NC, Duke-SC) to account for state-specific RPS/CES.

Inputs

• Primary Files: Two Excel files from the EIA Form 861 dataset:
  • Utility_Data_[YEAR]_Data_Early_Release.xlsx: Provides utility characteristics (e.g., name, ownership type, NERC region) but lists only a primary state per utility.
  • Sales_Ult_Cust_[YEAR]_Data_Early_Release.xlsx: Breaks down retail sales (MWh), revenues, and customers by state, sector (residential, commercial, industrial, transportation), and service type (bundled, energy-only, delivery-only). This is the key file for identifying multi-state operations via non-zero sales.
• Temporal Scope: Use the most recent early release (e.g., for calendar year 2024 data, released August 2025). Final edited data follows later, but isn't required for our preliminary pairs.
• Additional Context: EIA's data dictionary (embedded in files or via their site) for column mappings; we filter for US states/territories, excluding withheld utilities (ID 88888) or adjustments (ID 99999).

Public Data URLs

All data is publicly available from the U.S. Energy Information Administration (EIA). The primary download page is:

• https://www.eia.gov/electricity/data/eia861/ – Download the ZIP archive (e.g., f8612024er.zip for 2024 early release), which contains the two Excel files.

For monthly updates or related data (e.g., Form 861M for interim sales):

• https://www.eia.gov/electricity/data/eia861m/ – But we prioritize annual for comprehensive pairs.

Historical or revised data (e.g., corrections):

• https://www.eia.gov/electricity/data/eia861/correction.html

Third-party archives (for reference, not primary use):

• Catalyst Cooperative PUDL (processed EIA data): https://catalystcoop-pudl.readthedocs.io/en/stable/data_sources/eia861.html

We download fresh each year to ensure currency, archiving with timestamps for audits.

Step-by-Step Process to Create the List

We process the data in code (e.g., Python with pandas) or manually in Excel for validation. Here's the reproducible method:

1. Download and Extract Data:
   • Access the ZIP from the EIA URL above.
   • Extract the two XLSX files. Note EIA's disclaimer: Early releases are unedited; do not aggregate to totals without caution.
2. Prepare Utility Characteristics (from Utility_Data File):
   • Load the 'States' and 'Territories' sheets (skip first 2-3 rows for headers/notes).
   • Key columns: Utility Number (ID), Utility Name, State (primary), Ownership Type (e.g., Investor Owned, Municipal).
   • This file gives ~3,300 utilities but only one state per row—use for joining names/ownership later.
3. Identify Active States (from Sales_Ult_Cust File):
   • Load the 'States' and 'Territories' sheets (skip 3-4 rows for headers/notes).
   • Key columns: Utility Number, Utility Name, State, Ownership, TOTAL Sales (Megawatthours), TOTAL Customers.
   • Filter rows where TOTAL Sales > 0 or TOTAL Customers > 0 (to confirm active retail service).
   • Aggregate across Parts (A: Bundled, B: Energy-only, C: Delivery-only, D: Other)—sum A+B+D for sales/customers per EIA notes to avoid double-counting delivery.
   • Drop adjustments (Utility Number 99999) and withheld (88888).
4. Generate Unique Pairs:
   • Group by Utility Number + State.
   • Deduplicate to create pairs (e.g., ~4,000 total US pairs, including territories).
   • Join with Utility_Data for enriched details (name, ownership, NERC region).
   • Prioritize: Sort by total_sales descending for SSS focus (e.g., top IOUs like PG&E-CA with high RPS load).
5. Validation and Outputs:
   • Cross-check: Pairs should match known multi-state ops (e.g., AEP in OH, TX).
   • Export: CSV or SQL table (e.g., utility_state_pairs with columns: utility_number, state, utility_name, ownership, total_sales_mwh).
   • Usage in SSS: Pairs feed pro-rata calcs (customer_load / total_sales_mwh per state); filter for CA to isolate PG&E-CA.

This yields a clean list for our registry—e.g., PG&E-CA with ~33 TWh sales in 2023. For audits, we archive raw files and code; refresh annually post-EIA release.