Solar + Battery Savings Calculator

☀️ Solar Panels

Number of panels

Watts per panel

Cost per panel

USD each

Annual avg peak sun hrs

hrs/day · Noe Valley ≈ 5.2

Solar production during peak hours (4–9 PM)

% of daily output · south-facing in SF ≈ 20–30%

Daytime electricity use (8 AM – 4 PM)

kWh · home consumes during solar production hours

⚡ PG&E E-TOU-C / E-TOU-C3 Rates

Peak window: 4 PM – 9 PM every day (incl. weekends & holidays) · E-TOU-C tariff ↗ · CleanPowerSF rates ↗

Peak rate

$/kWh · 4–9 PM

Off-peak rate

$/kWh · all other hours

Solar export / NEM 3.0 rate

$/kWh · what grid pays for exported solar (0 = plug-and-play, no export)

Rates effective March 2026. E-TOU-C3 (CleanPowerSF) uses the same schedule but different $/kWh — update above with your actual bill rates. Baseline credit of −$0.0814/kWh applies to first ~6–8 kWh/day and is not modeled here.

📊 Solar Summary

System capacity

1.60kW peak

Annual production

—kWh/yr

Annual solar savings

—/yr

Panel investment

$800

Panel-only payback

—

📅 Monthly Solar Profile — Noe Valley, SF

Summer season (4PM peak $0.52) Winter season (4PM peak $0.40)

SF fog pattern: Noe Valley sits in the fog shadow of Twin Peaks — noticeably sunnier than the Sunset or Richmond. April and September are the peak months (clearest skies). June Gloom (late-May through mid-July) suppresses production despite long days. The monthly bars above reflect NREL irradiance data scaled to your peak sun hours setting.

Avg % sunny days by month

📋 Side-by-Side Comparison

Model notes: Solar savings = directly self-consumed solar at applicable rate (peak or off-peak). Battery solar value = excess solar stored and discharged at peak rate (upgraded from off-peak or zero for plug-and-play). Battery grid value = remaining capacity charged from grid at off-peak, discharged at peak (spread). Monthly irradiance from NREL data for Noe Valley (37.75°N, −122.43°W), scaled to your PSH input. Degradation (~0.5%/yr), NEM export of excess beyond battery capacity, permits, and install costs not modeled.