London is served by UK Power Networks and sits in its own electricity region. On Octopus rates for 26 September 2026 a battery on Flux buys at 15.29p (2am to 5am) and avoids 35.66p (4pm to 7pm). In this site's model a 10 kWh battery saves about £414 a year with 4 kWp of solar on Flux, and £335 a year with no solar on Agile Octopus, the highest battery-only figure of any region. The limiting factor is usually finding a PAS 63100-compliant location.
Your electricity region and network operator
London is a single electricity region with one network operator:
| Electricity region | Network operator (DNO) | Flat unit rate | Standing charge (pence a day) |
|---|---|---|---|
| London (C) | UK Power Networks (London Power Networks) | 26.35p/kWh | 41.50 |
What a battery can buy low and use high
The rates that decide a battery's saving in London:
| Rate | London |
|---|---|
| Octopus Flux import, 2am to 5am | 15.29p |
| Octopus Flux import, 4pm to 7pm | 35.66p |
| Octopus Flux export, 4pm to 7pm | 28.60p |
| Octopus Go overnight import | 8.62p |
| Octopus Go daytime import | 30.99p |
| Outgoing Octopus flat export | 12.00p |
| Agile Octopus, average of each day's cheapest 3 hours | 13.46p |
| Agile Octopus, average 4pm to 7pm | 43.40p |
| Flux spread: peak import minus off-peak | 20.37p |
Solar yield across London
Modelled output of a 4 kWp south-facing array:
| Place | kWh a year | June | December | Electricity region |
|---|---|---|---|---|
| London | 4,075 | 490 | 145 | London |
How often the power goes off
Ofgem's reliability figures for the networks serving London (lower is better):
| Network area | Interruptions per 100 customers | Minutes lost per customer | Against the GB average |
|---|---|---|---|
| London | 11.2 | 10.46 | Fewer minutes lost |
Solar already on London's roofs: DESNZ counts 65,504 domestic-scale solar installations in London (252.3 MW) at the end of Jul 2026.
A home in London using 3,000 kWh a year, with 4 kWp of solar, adds a 10 kWh battery. Yearly savings with London's solar yield and London rates, against no battery on a flat tariff:
| Tariff with the battery | Modelled saving a year | Energy charged from the grid |
|---|---|---|
| Octopus Flux, selling spare stored energy at the peak | £414 | 1,165 kWh |
| Staying on a flat tariff (solar storage only) | £174 | 0 kWh |
| Same home with no solar, battery on Agile Octopus | £335 | 3,258 kWh |
| Same home with no solar and an electric car, battery on Octopus Go | £489 | 3,258 kWh |
Flux needs solar panels and Go is for electric car owners. How the model works · try your own numbers.
What makes London different
The cheapest standing charge. London’s Flexible Octopus standing charge was 41.50p a day on 26 September 2026, the lowest of the fourteen regions. Standing charges do not change a battery’s saving, but they are why London households’ bills are more sensitive to unit rates, which is what a battery works on.
The most reliable network. Ofgem’s 2024/25 figures put London Power Networks at 11.2 interruptions per 100 customers and 10.46 minutes lost per customer, against a GB average of about 40 and 35. For most London homes, backup is a nice-to-have rather than the reason to buy.
Fewer roofs, more flats. DESNZ counts 65,504 domestic-scale solar installations in London at the end of July 2026, the fewest of any English region. That makes the battery-only case, charging from the grid on a time-of-use tariff, more important here than elsewhere. Octopus Flux requires solar panels, so battery-only homes in London look at Agile Octopus or, with an electric car, an overnight EV tariff.
Where a battery can go in a London home
PAS 63100, the BSI fire-safety specification for batteries in homes, is the practical constraint in the capital:
- Terraces: a rear outside wall or a side return is often the best spot, as long as the battery is at least 1 m from doors, windows, vents and escape routes. An integral garage can work.
- Flats: bedrooms, hallways and landings (escape routes) and lofts are ruled out. A utility cupboard is only possible if it has 30-minute fire separation, ventilation to outside and does not open into a bedroom. A balcony is outside but still subject to the 1 m rule.
- Basements: a cellar with no access to the outside is ruled out.
Leaseholders also need the freeholder’s consent for anything on the building’s structure, and listed buildings need listed building consent where the work affects their character.
The London numbers
The tables above show the region’s published tariff rates and PVGIS yield. For a 4 kWp south-facing array, PVGIS models 4,075 kWh a year in London, 490 kWh in June and 145 kWh in December. That winter figure is why a London solar battery earns most of its winter keep from cheap-rate grid charging rather than from the panels.
On Octopus Flux the gap between the 4pm to 7pm peak (35.66p) and the 2am to 5am rate (15.29p) is 20.37p, and exported energy in the peak earns 28.60p. That is the arithmetic behind the modelled £414 a year for a 10 kWh battery with solar.
Funding in London
There is no London-specific battery grant. Installed home batteries carry 0% VAT until 31 March 2027. Eligible low-income households can ask their borough about the Warm Homes: Local Grant, which can include a battery only alongside new or existing solar panels, and the government’s Warm Homes Loan Scheme offers lower-interest loans of up to £15,000 for a battery. See grants and funding.
Getting quotes in London
Ask each installer where they would put the battery and why that location complies with PAS 63100, before you compare prices; a quote that assumes a hallway or loft is not a real quote. Then compare the usable kWh and price per kWh. Request battery storage quotes (we reply by email) and put each through the quote checker.
Home batteries in London: questions
Who is the network operator for London?
UK Power Networks, through its London Power Networks licence. Your installer notifies it of a small battery within 28 days of commissioning, or applies before installation for a larger system. UK Power Networks says it automatically approves applications where the maximum export after any export limitation is under 5 kW.
Can I have a home battery in a London flat?
Sometimes. PAS 63100 rules out bedrooms, escape routes (which in a flat usually includes the hallway), lofts and voids. A balcony or outside wall must be at least 1 m from doors, windows and vents. You will also need the freeholder's permission for anything outside your demise, and some blocks forbid it.
Is a battery worth it in London without solar?
London has the highest modelled battery-only saving of any region on Agile Octopus, about £335 a year for a 10 kWh battery in a home using 3,000 kWh, because its cheap Agile hours averaged 13.46p over the 30 days to 26 September 2026. At Octopus's published £5,336 for 10 kWh, that is a payback of around 16 years.
Do I need planning permission for a battery in London?
An indoor battery is generally not development that needs planning permission. An external unit on a listed building needs listed building consent if it affects the building's character, and PAS 63100 notes that equipment on an external wall can sometimes need planning consent. Check with your borough if you are in a conservation area.