UK Solar Battery & SEG Guide: ROI & Payback 2026

Unlike the US where many states have full-retail net metering (crediting exports at the same rate you pay for imports), the UK has no net metering scheme. Instead, the SEG requires large energy suppliers to pay you a separate, usually lower, rate for any solar electricity you export to the grid. This creates a massive incentive to self-consume as much of your solar production as possible: every kWh you use yourself saves you 24.67p, while every kWh you export earns you only 6–27p depending on your supplier. A battery lets you store excess midday solar production to use in the evening when you would otherwise be buying expensive grid power, rather than exporting it for a low SEG rate.

SEG rates vary by up to 4.5× between suppliers, so choosing the right one can make a huge difference to your solar returns. As of June 2026, the main supplier rates are: <br><br> <strong>Octopus Energy Intelligent Flux:</strong> 25–27p/kWh for exports during peak periods (4–7pm), 15p/kWh off-peak <br> <strong>Good Energy:</strong> 20p/kWh flat rate <br> <strong>E.ON Next:</strong> 16.5p/kWh flat rate <br> <strong>Scottish Power:</strong> 6p/kWh flat rate <br> <strong>British Gas:</strong> 12p/kWh flat rate <br><br> For a typical 3.5kW system exporting 2,000 kWh/year, this means annual export earnings range from £120 (Scottish Power) to £540 (Octopus Intelligent Flux peak exports) — a £420 per year difference. If you have a battery, you can choose to export only during peak rate periods, maximizing your SEG income while using stored solar for your own evening consumption.

A battery improves your solar return in three key ways: <br><br> 1. <strong>Increased self-consumption:</strong> Solar-only systems typically self-consume ~30% of their production, exporting the other 70% for low SEG rates. Adding a battery increases self-consumption to 70%+ by storing excess midday production for evening use, saving you 24.67p/kWh instead of earning 6–27p/kWh for exports. <br> 2. <strong>Time-of-use tariff arbitrage:</strong> If you're on a time-of-use tariff like Octopus Agile, you can charge your battery from the grid during off-peak periods when electricity is cheap (as low as 5p/kWh) and discharge it during peak periods when it's expensive (30p+/kWh), even when there's no solar production. <br> 3. <strong>Peak SEG exports:</strong> With a battery, you can hold onto your excess solar production until peak SEG rate periods (usually 4–7pm) to earn the highest possible export rate, rather than exporting it midday when rates are often lower. <br><br> For a typical home, these three benefits can add £400–£700 per year to your solar savings, reducing payback time for the battery to 6–10 years.

Yes, solar is still worth it in the UK even without net metering, especially with the 0% VAT relief until March 2027. The key is to maximize self-consumption: if you use 70%+ of your solar production (easily achievable with a battery), you're saving 24.67p/kWh on each of those kWh, which adds up quickly. Even without a battery, a 3.5kW system with 30% self-consumption and a 15p/kWh SEG rate will save you ~£450 per year, giving a payback period of 11–13 years. With a battery increasing self-consumption to 70%, annual savings jump to ~£700 per year, reducing payback to 7–9 years for the combined solar + battery system.

A typical 5 kWh battery costs £3,000–£4,500 installed, while a 10 kWh battery costs £5,000–£7,000. When installed at the same time as solar panels, batteries qualify for the 0% VAT relief until 31 March 2027, saving you 20% on the cost. In Scotland, you may also qualify for up to £6,000 in Home Energy Scotland grants for solar + battery systems. To be eligible for SEG payments and warranty coverage, your battery installation must be carried out by an MCS-certified installer using MCS-certified equipment, just like your solar panels. Most battery warranties cover 10 years and 60–80% of original capacity after that period.