What Happens to Extra Solar Energy?

Self-Consumption First

The most direct use of solar energy is powering your home in real time. When you run appliances during daylight hours, solar generation reduces the amount of electricity you import from the grid. This is called self-consumption, and it typically provides the best value because you avoid buying that unit of electricity at your import rate.

Maximising self-consumption does not require a battery - it requires alignment between generation and usage. Running washing machines, dishwashers, or charging devices during sunny periods increases self-consumption without additional hardware. However, many households have their highest demand in the evening when solar output is low or zero, which limits self-consumption without storage.

Battery Charging

If you have battery storage and the battery is not full, surplus generation can charge it rather than flowing to the grid. The stored energy is then available for evening use. This effectively shifts self-consumption from daytime to nighttime.

Once the battery reaches its configured maximum charge, it can accept no more. Further surplus must either be consumed by active loads or exported. Battery capacity therefore sets an upper limit on how much surplus can be captured for later use.

Export to the Grid

When generation exceeds household demand and battery capacity (if present), the remaining energy flows to the national grid through your metered connection. This is export. Your smart meter or export meter records the volume of exported energy, which may be relevant if you have an export tariff arrangement with your supplier.

Export is a normal part of grid-connected solar operation. The grid acts as an unlimited sink for surplus energy during sunny periods, and as a source of supply when generation is insufficient. You do not need to "switch off" export manually - the system manages the balance automatically.

Export Tariffs in General Terms

Some energy suppliers offer payments for exported solar energy under schemes such as the Smart Export Guarantee (SEG) or proprietary export tariffs. Rates, eligibility and terms vary between suppliers and change over time. Some tariffs pay a flat rate per kilowatt-hour exported; others may offer time-varying rates.

Export income is one component of a solar system's overall value, but it is rarely the largest. Self-consumption typically avoids a higher cost (your import rate) than export earns (your export rate). The relative importance of export depends on your usage pattern, system size and the tariffs available to you. We do not quote specific rates here because they change and vary by supplier.

Why Timing Matters

Solar generation follows the sun - peaking around midday and falling to zero at night. Household demand often peaks in the morning and evening. This mismatch means that even well-sized systems may export significantly during summer weekdays when the home is empty, while importing in the evening.

Understanding this timing mismatch helps explain why batteries, EV charging schedules, and flexible appliance use can all influence how much value you derive from solar. It also explains why generic financial projections that assume constant self-consumption rates may not reflect your actual experience.

How System Design Affects Value

A system that is oversized relative to daytime consumption will export more. A system that is undersized may rarely produce surplus. Adding battery storage shifts energy from export to delayed self-consumption. Adding an EV charger creates a new daytime load that can absorb surplus - where timing and design allow.

None of these outcomes is inherently "better" without context. The right design depends on your property, usage, tariff and goals. A technical review is needed before installation decisions are made, as the optimal balance between system size, storage and export strategy is property-specific.

What a Technical Review Should Check

• What export tariff, if any, is available through your current or a prospective supplier
• How your household's demand pattern compares with typical generation timing on your roof
• Whether battery storage or shifting appliance use would capture more value than export alone
• Whether the proposed system size matches realistic self-consumption, rather than maximising panel count