Methodology validation: Rate structure, tier breakpoints, and adder percentages validated directly against Georgia Power's official Power and Light Calculator at georgiapower.com. Both PLM (Medium, 30-499 kW demand) and PLL (Large, 500+ kW demand) rate structures are implemented. Tariff selection is automatic based on actual peak demand (pre-BDAF). Results from this tool match the GA Power calculator to the penny across scenarios from 50 kW / 5,000 kWh up to 998 kW / 500,000 kWh. The TOU-EVC-4 dedicated EV charging schedule ($152/mo · $5.25/kW · 24.4008¢ on-peak 2-7pm weekdays Jun-Sep · 6.1002¢ off-peak) is also implemented and validated against a real July 2026 commercial EV charging bill — ECCR, franchise fee, and sales tax lines reproduce to the penny. Its on-peak kWh share comes from the selected site type's hourly load shape, built from Tesla's published Busy Times profiles for all 90 open Georgia Supercharger sites (Sep 2026; retail 20.1%, highway 22.3%, parking / urban 19.3%); the real bill's 22.2% can be entered as an override in the Advanced panel. The Rate Plan selector offers PLM/PLL + CIEV, TOU-EVC-4, RTP-DA and TOU-SC MAC; Auto selects RTP-DA whenever the modeled peak clears 250 kW and otherwise rides the CIEV rider until the 15% load-factor ceiling, then switches one-way to TOU (operator-reported sequencing; confirm with Georgia Power). RTP-DA and TOU-SC MAC follow the published RTP-DA-13 and TOU-SC-16 schedules using a flat annual hourly price with a Jun–Sep premium, set from Georgia Power's Sep 2026 guidance to model a 7.5–8.6¢ flat average, plus a summer weekday 2-7pm intra-day premium (default 2.0× the day average, other hours scaled to preserve it) weighted by the site type's Tesla Busy Times load shape; Georgia Power does not publish hourly price history, so treat both as indicative until your rep supplies 24 months of prices and a CBL or MAC quote.
Peak demand modeling: Tesla Model Y is used as the 2026 reference vehicle (peak ~250 kW brief, average ~150 kW sustained during the 30-minute billing demand window). As 800V / 500 kW-class vehicles penetrate the fleet, the sustained average is modeled rising ~6%/yr to a ~240 kW plateau by the mid-2030s — 500 kW itself is a fleeting peak (a Cybertruck's full V4 session still averages ~150 kW). Cabinet demand follows how many cars charge simultaneously in the busiest hour: stalls × utilization × the site type's busiest-hour ratio from its Tesla Busy Times load shape (retail 1.57, highway 1.77, parking / urban 1.41), plus a small headroom for the month's single worst 30-minute window — calibrated to a real 8-stall metro retail bill (559 kW at 27% utilization, July 2026) — floored at one car and capped at 998 kW per cabinet (1,996 kW for 2-cabinet sites). Because it tracks utilization, billing demand grows with the site over the projection. Rising fleet speeds also lift the utilization kWh ceiling, at half strength — charge time shrinks but dwell time doesn't.