Solar Self-Consumption Scenario Calculator

How the solar self-consumption scenario calculator works

Generation and load are supplied energies for the same three intervals. Direct self-used energy in each interval is the smaller of generation and load. Only after that comparison are self-use amounts summed. Total excess is total generation less self-use; total import is total load less self-use. No energy carries between intervals.

Self-consumption percentage divides summed self-use by total generation and is unavailable at zero generation. The entered positive durations allow an average generation-power output from total generation divided by total hours; they do not change the supplied interval energies. The selected interval length must fit the physical and measurement boundary.

This assumes uncapped permitted export and no storage or curtailment. Interval totals can still hide mismatch within an interval, so unrelated annual totals cannot establish actual self-consumption. No tariff credit, instantaneous power rating, meter netting rule, demand-charge result or dispatch schedule is calculated.

Worked example

Three one-hour intervals have generation 10, 6 and 0 kWh and loads 6, 9 and 2 kWh. Direct self-use is 6 + 6 + 0 = 12 kWh out of 16 generated, or 75%. Excess export is 4 kWh and import is 5 kWh. Increasing first-interval load to 10 kWh raises self-use to 16 kWh and the percentage to 100%.

Sources and assumptions

The source material explains the underlying calculation or pricing structure. Entered prices, costs, schedules and scenario choices are your assumptions; this tool does not obtain supplier quotes or predict actual results.

• SAM: energy, demand and time-matched export billing
• SAM: PVWatts model inputs and scope