Methodology
The Volt Resilience Score is a transparent comparative index. It is deliberately not an outage prediction, engineering calculation, insurance score or safety rating.
Solar recharge
Annual AC output from a standardized 10 kW roof-mounted PV system, normalized across the indexed cities.
Seasonality
The weakest modeled solar month relative to the system's average month. Less seasonal output scores higher.
Hazard resilience
A simple inverse proxy based on matching federal disaster declarations in the location's county over the lookback window.
Affordability
Residential electricity price. Lower prices score higher because grid energy is less economically burdensome.
Standard assumptions
PV simulations use a 10 kW DC nameplate system, standard modules, 14% system losses, a fixed roof-mounted array, south-facing azimuth where applicable, and a tilt based on location latitude within practical bounds. These assumptions create comparability; they are not a recommendation for a specific property.
Hazard limitation
Federal disaster declarations are a coarse historical proxy. They do not measure outage frequency, outage duration, utility reliability, expected annual loss or the probability that an individual home will lose power. A future methodology version may incorporate additional reliability datasets where nationally consistent public data are available.
Score normalization
Each component is converted to a 0–100 scale and then combined using the published weights. Scores are intended to be interpreted relative to other cities in this index, not as absolute probabilities.
Starter vs refreshed data
The repository ships with a starter dataset so the site renders immediately. The GitHub updater replaces available fields with live-source data and preserves the previous value when an upstream API is unavailable.