Solar panels do not simply reduce your bill by the amount they generate. What matters is where each unit of electricity goes at the moment it is produced.
Adjust the generation and household demand below to see how the split changes between electricity used directly in the home, electricity exported to the grid, and electricity still imported when the panels cannot cover demand.
This visualiser has a lot to show at once and works best on a tablet or desktop. On a phone you may need to scroll within it.
The four flows explained
- Generation
- Everything the panels produce. It varies with sunlight, season, roof direction, pitch, shading and panel temperature.
- Self-consumption
- Solar electricity used in the home at the moment it is generated. This is the most valuable outcome, because each unit avoids buying electricity at the full import price.
- Export
- Surplus solar sent to the grid when generation exceeds demand. It earns the export rate, which is normally well below the import price.
- Grid import
- Electricity bought when demand exceeds generation — overnight, in winter, and whenever an appliance draws more than the panels are producing.
Why the split matters more than the total
Two homes can generate exactly the same number of kilowatt-hours in a year and save very different amounts of money.
A home with daytime occupancy, an EV charging in the afternoon or a hot-water diverter will consume much of its own generation directly. A home that is empty during the day will export a larger share and buy it back later at a higher price.
That is the gap a battery is designed to close: it moves surplus generation from the middle of the day to the evening, converting export into self-consumption. It cannot create electricity the panels never produced, so it helps far less in winter than in summer.
Reading the model
This is a simplified illustration for understanding the relationships, not a generation forecast for your property. A real estimate needs your postcode, roof direction, pitch, shading and half-hourly consumption data.
Go deeper on solar energy flows
- Solar Export Explained — SEG rates, export limits and what surplus is worth
- Smart Meters and Half-Hourly Data — finding out when your home actually uses electricity
- Solar, Battery and EV Working Together — how the three interact and where they conflict
- Adding a Battery to Existing Solar — converting export into self-consumption
- Is Your Home Suitable for Solar Panels? — the starting point for any solar decision
Understand solar before you buy
How much you save depends on when you use electricity, not just how much the panels generate.