Hourly vs monthly mean-day: where the error appears

Illustration on one typical year (NREL TMY3, Greensboro NC) and a synthetic home load. Not a site estimate. Inverter efficiency 96%, AC-coupled battery, charged from surplus only.

Array size (kWp)

DC/AC ratio

Annual load (kWh)

Battery usable energy (kWh, 0 for none)

Battery power (kW)

Round-trip efficiency (%)

Import price 16:00-21:00 (USD/kWh)

Import price other hours (USD/kWh)

Export price (USD/kWh)