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The consumption profile on the Energy page needs to be “before solar”, i.e., the customer’s actual consumption - not the net energy imported from the grid (ie reduced consumption due to existing solar). See more about this here.
The solar export earnings from the existing system do not contribute towards the payback/ROI of the battery
The payback periods for battery-only upgrades on existing solar are usually quite long.
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Alternatively, you can use a typical consumption profile from the library and estimate the average daily kWh. You can make an educated guess by checking the current consumption based on the current bill + (estimated solar generation from old/existing system - solar export from the old/existing system).
Note the average daily grid energy usage on the current bill
Note the average daily solar export on the current bill
Estimate the average daily production of the existing solar system.
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Total consumption = [existing solar production] - [solar export] + [grid usage] |
So if the site is using 10 kWh/day currently as per the energy bill and the site has an old 4 kW system that produces 12 kWh/day and is exporting 5 kWh/day, the actual consumption would be 10 + ( 12 - 5 ) + 10 = 17 kWh, assuming the old system produces 12 kWh/day.