Do I need solar panels to have a battery?
Short answer
It can be, if you have a big gap between cheap and peak electricity prices and enough use in peak hours. The battery charges overnight and runs the home later. Savings depend on tariff eligibility, round-trip losses and future tariff changes, and battery-only homes cannot earn SEG export payments.
Last checked 24 September 2026 · 5 sources
What should I know before deciding?
SEG eligible technologies are generation only (solar, wind, micro-CHP, hydro, AD).
Can I get a cheap overnight EV tariff if I only have a battery?
Mostly not, by the terms. Octopus Go and Intelligent Go, E.ON Next Drive, EDF GoElectric and British Gas's EV tariff all require an electric car. Octopus Flux and Intelligent Flux need solar and a battery; Cosy needs a heat pump. Agile and Tracker only need a smart meter. Some battery-only households have been moved off EV tariffs.
Octopus Go T&C v1.6 (10 Apr 2025): for customers who own or long-term lease a BEV or PHEV; otherwise Octopus may move you to a more appropriate tariff. Intelligent Octopus Go v2.6 (16 Feb 2026): for customers with a BEV/PHEV charging primarily at home; register the device in the app within 7 days; max 6 hours of managed charging per 24h. Octopus Flux v2.9 and Intelligent Flux v2.6: solar PV and a home battery (Intelligent Flux: battery of a type approved by Octopus).
Will my battery keep the lights on in a power cut?
Only if it was installed for backup. Grid-tied batteries must shut down when the grid fails unless an EPS or a backup gateway isolates the house. An EPS socket or backup circuit powers a few chosen loads, often limited to about 16 A; a whole-home gateway can run most of the house. Switchover can take milliseconds to several seconds.
No backup: battery and solar stop in a cut (anti-islanding under G98/G99). EPS: one outlet or a few circuits (myenergi libbi backup 16-20 A; GivEnergy 2023 guide ~5 s delay). Whole-home gateway: needs space near the meter, an earth electrode for island mode (MIS 3012), and the backup reserve set.
Should I buy a battery before solar panels?
It can make sense if your roof is poor, you are on a cheap overnight tariff, or you want backup: a battery alone can shift cheap night electricity into the evening peak. For most homes with a good roof, panels first offer the better return, and a hybrid inverter or battery-ready design keeps the upgrade path open.
Battery-only value comes entirely from the gap between off-peak and peak import prices (e.g. IOG six-hour window) minus round-trip losses. SEG does not pay for exporting grid-charged battery energy unless the supplier chooses to. 0% VAT on standalone batteries in GB applies only within the relief's rules and dates - see scheme_status rows.
What to do next
Use your own half-hourly electricity data where possible. Compare usable kWh, kW, tariff rules and warranty terms before buying.
Sources
- Ofgem — www.ofgem.gov.uk/sites/default/files/docs/2018/06/final_storage_guidance_0.pdf
- Octopus Energy — octopus.energy/policies/smart-tariffs-terms-and-condition/
- forums.moneysavingexpert.com — forums.moneysavingexpert.com/discussion/6635208/eon-next-have-removed-next-driv…
- ovoenergy.com — www.ovoenergy.com/terms/charge-anytime/add-on-plan-details
- Octopus Energy — octopus.energy/smart/intelligent-octopus-go/
Last checked: 24 September 2026