Short answer: not unless it was designed to. A standard home battery in Twickenham, or anywhere else in Great Britain, switches off with the grid during a power cut. That can come as a surprise, because the battery may be full of stored energy at the time.
This guide explains why that happens, what real backup involves, how reliable the network around Twickenham actually is, and how the grid rules for G98, G99 and export limits apply in TW1 and TW2. For the wider battery decision, including size, cost and where a unit goes in Twickenham’s homes, see our Twickenham battery storage guide.
Why a full battery goes dark
Inverters connected to the grid are required to disconnect when the network goes down. The reason is safety. If they kept running, they could feed electricity back into cables that engineers are working on, believing them to be dead. Your panels and battery stop at the same moment as your neighbours’ supply, and restart when the network returns.
That is the default for a standard grid-tied system, and it is how most batteries are installed. It does no harm in normal use. It only matters if you were counting on the battery during a cut.
What backup actually takes
A system that keeps some power on in a cut needs three things:
- A battery and inverter that support backup operation. Not all do, and some need an extra module.
- Switching equipment that isolates your home from the grid automatically, so the battery can safely run your circuits.
- A decision about which circuits. Usually that means a protected set, such as the fridge, lights, router and perhaps a boiler’s controls, rather than the whole house.
Each of these adds cost and design work. If backup matters to you, ask for it by name, check it appears as a separate line in the quote, and ask what the system does during a cut, in writing. If a quote is silent on backup, assume the battery does not provide it.
How often the lights actually go out
Ofgem publishes network reliability for each licence area. For UK Power Networks’ South Eastern Power Networks area in 2024/25, it records:
| Measure | 2024/25 | 2023/24 | Ofgem target 2024/25 |
|---|---|---|---|
| Interruptions per 100 customers | about 42.2 | about 49.5 | 42.5 |
| Minutes lost per customer | about 30.4 | about 36.5 | 31.2 |
Both measures were within target. For comparison, the average across all 14 licence areas was about 39.7 interruptions and 35.1 minutes. These figures cover a licence area that runs across south London, Kent, Sussex and part of Surrey, not Twickenham alone. Ofgem notes that severe-weather adjustments were applied, so treat them as reported rather than final. They are not a reason to buy a battery for backup. They are useful context if you are deciding whether backup is worth paying for.
Which network is yours
Twickenham’s town centre sits in UK Power Networks’ South Eastern Power Networks area, but the boundary with SSEN Distribution’s Southern Electric Power Distribution area is only about 1.2 km away. Do not assume from the postcode. Use the network operator’s area checker for your own address. Your installer sends the paperwork to whichever operator serves your home.
G98, G99 and export limits
The rules depend on the total size of your inverters, and a battery’s inverter counts:
- Up to 16 A per phase (3.68 kW): the system is type-tested and notified under G98, before commissioning or within 28 days after it.
- Above 16 A per phase: a G99 application must be approved before work starts. A 4 kW inverter draws 17.39 A, just over the line, so a battery added to an existing array can push the total over it.
- Export limitation: UK Power Networks says it automatically approves an application where the maximum export, after any export limitation scheme, is under 5 kW. An export limit caps what the system can send to the grid, whatever the inverters could produce.
Through Smart Connect, approved installers handle these forms for UKPN on your behalf. If UKPN finds your supply cannot take the extra load, it may need to upgrade it first. It says there is nothing to pay it if no upgrade is needed. On SSEN’s side the same G98 and G99 thresholds apply.
Twickenham’s place in this
Across Richmond upon Thames, DESNZ records about 2,608 solar PV installations of all sizes at the end of 2025, with 10.15 MW of capacity, as first published. Every new battery added to one of those arrays, or fitted alongside new panels, goes through the G98 or G99 step above. The paperwork is your installer’s job. Your job is to be clear about what you want the system to do in a power cut, and to get that in writing.
For how batteries work day to day, see our guide to solar battery storage. For sizing, see our guide to what size home battery you need. If you are pairing a battery with panels, our solar panels Twickenham page covers the conservation areas and Richmond’s £600 MakeMyHouseGreen solar discount. For the wider area, see solar panels in South West London.
Sources: Ofgem, RIIO-2 Electricity Distribution annual report 2024 to 2025 and supplementary datafile (published 15 January 2026); UK Power Networks, licence boundaries, Smart Connect, and Solar and storage: cost, time and what’s involved; NESO, GB DNO licence area boundaries; ENA EREC G98 Issue 2 (10 March 2025); DESNZ, Renewable electricity by local authority 2014 to 2025 (published 29 September 2026); London Borough of Richmond upon Thames, Save on solar with MakeMyHouseGreen.