Methodology → Electricity Price Index™
Electricity Price Index™ Methodology
The Electricity Price Index™ (EPI) normalizes state electricity rates to a national baseline, making it easy to compare states at a glance.
National average baseline
The national average residential electricity rate (¢/kWh) across all 50 states is used as the baseline. This baseline is assigned an index value of 100.
Formula
For each state:
indexValue = round((stateRate / nationalAverage) × 100)
Where stateRate is the state's average residential electricity price in ¢/kWh, and nationalAverage is the mean across all 50 states.
Interpretation
- Index > 100 — Above national average (higher electricity prices)
- Index = 100 — At national average
- Index < 100 — Below national average (lower electricity prices)
Limitations
The EPI uses state-level averages only. It does not account for within-state variation, time-of-use rates, or customer class differences. Rates are energy-only and exclude delivery, taxes, and fixed fees.
Data sources
State rates come from our normalized data pipeline. See sources for provenance.