Why your bill looks different
Before solar, your electricity bill was straightforward: units consumed × unit rate + standing charge. After solar, your meter arrangement changes. If you have a smart meter (which most installations now require), the meter records both import (electricity drawn from the grid) and export (electricity sent to the grid) separately.
Your electricity bill should now show import consumption only — the units you consumed from the grid, not the total electricity your home used. The solar generation is not billed; it is either self-consumed (free) or exported (paid via your SEG contract). If your bill still shows the same consumption as before solar, either your self-consumption is very low or your meter is not reading correctly.
Where your SEG payments appear
Smart Export Guarantee payments are usually processed separately from your main electricity import bill. Depending on whether your SEG provider is the same as your import supplier, the payment may appear as a credit on your electricity bill or as a separate direct payment to your bank account.
SEG payments are made in arrears, typically monthly or quarterly. The payment is based on metered export — the actual kWh registered by your export meter. If you suspect your SEG payment is lower than it should be, compare the export kWh figure on your bill against the export figure shown in your inverter's monitoring portal for the same period. Significant discrepancy (more than 5%) is worth querying with your supplier.
Interpreting the numbers — a worked example
Suppose your monitoring portal shows your 4 kWp system generated 3,200 kWh in the past year. Your electricity bill shows you imported 2,400 kWh from the grid. Your SEG statement shows 1,100 kWh exported.
Self-consumed solar = Total generation − Export = 3,200 − 1,100 = 2,100 kWh. Total household consumption = Import + Self-consumed = 2,400 + 2,100 = 4,500 kWh per year. Self-consumption rate = 2,100 / 3,200 = 66%. Export rate = 1,100 / 3,200 = 34%.
These ratios tell you how the system is performing. A self-consumption rate of 50–70% is typical for a well-matched system with no battery. If your self-consumption rate is below 40%, you are exporting more than half your generation — a battery or diverter might improve the financial return.
Common billing problems to watch for
Smart meter export not registered: Some smart meters in the UK require a separate firmware update or configuration change to log export accurately. If your SEG provider is receiving zero export readings but your monitoring portal shows significant export, contact your supplier to verify the meter's export function is enabled.
Estimated readings: If your supplier has sent an estimated bill without an actual smart meter reading, the import figure may be inaccurate. Ensure your smart meter is communicating and that your supplier is using actual readings.
SEG payments stopped: If your SEG payments have stopped without explanation, check whether your SEG contract has lapsed, whether your supplier requires an annual meter reading submission, or whether your inverter monitoring data shows a drop in export (which might indicate a real hardware issue rather than a billing problem).