Solar & battery
Grid-Tie Solar Calculator
Size a grid-tied system, where the grid handles the nights and the cloudy weeks.
Result
Grid-tied systems are sized on annual averages because the grid covers the gaps. This ignores interconnection limits, which some utilities set relative to your historical usage, and any requirement for a production meter or a separate solar tariff. A standard grid-tied inverter also shuts down in an outage.
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About this calculator
Can I install a system larger than my usage?
Often not. Many utilities cap interconnection at a percentage of historical consumption, and exporting heavily under net billing earns little anyway.
Does grid-tied solar work in a power cut?
Not by itself. The inverter disconnects to protect line workers. Running during an outage needs a hybrid inverter with a battery or a dedicated secure circuit.
The formula
kW = annual kWh needed / (peak sun hours x derate x 365)
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