Most of the South West is served by National Grid Electricity Distribution's South West licence area; Bournemouth and Poole are in SSEN's Southern area. Ofgem's 2024/25 figures give the South West 59.01 interruptions per 100 customers, the most in England. In this site's model a 10 kWh battery with 4 kWp of solar saves about £425 a year on Octopus Flux, but only about £250 a year with no solar on Agile, the second-lowest battery-only figure of any region.
Your electricity region and network operator
South West England spans 2 electricity regions, each with its own prices and network operator:
| Electricity region | Network operator (DNO) | Flat unit rate | Standing charge (pence a day) |
|---|---|---|---|
| South West England (L) | National Grid Electricity Distribution (South West) | 26.39p/kWh | 54.60 |
| Southern England (H) | SSEN (Southern Electric Power Distribution) | 26.42p/kWh | 46.41 |
What a battery can buy low and use high
The rates that decide a battery's saving in South West England:
| Rate | South West England | Southern England |
|---|---|---|
| Octopus Flux import, 2am to 5am | 15.33p | 15.34p |
| Octopus Flux import, 4pm to 7pm | 35.76p | 35.78p |
| Octopus Flux export, 4pm to 7pm | 29.22p | 29.00p |
| Octopus Go overnight import | 8.62p | 8.62p |
| Octopus Go daytime import | 31.17p | 31.29p |
| Outgoing Octopus flat export | 12.00p | 12.00p |
| Agile Octopus, average of each day's cheapest 3 hours | 16.01p | 14.31p |
| Agile Octopus, average 4pm to 7pm | 47.49p | 45.11p |
| Flux spread: peak import minus off-peak | 20.43p | 20.44p |
Solar yield across South West England
Modelled output of a 4 kWp south-facing array:
| Place | kWh a year | June | December | Electricity region |
|---|---|---|---|---|
| Bristol | 4,092 | 492 | 135 | South West England |
| Exeter | 4,209 | 501 | 141 | South West England |
| Plymouth | 4,488 | 552 | 144 | South West England |
| Truro | 4,262 | 518 | 137 | South West England |
| Bournemouth | 4,479 | 554 | 140 | Southern England |
How often the power goes off
Ofgem's reliability figures for the networks serving South West England (lower is better):
| Network area | Interruptions per 100 customers | Minutes lost per customer | Against the GB average |
|---|---|---|---|
| South Western England | 59.01 | 50.43 | More minutes lost |
| Southern England | 41.85 | 51.18 | More minutes lost |
Solar already on South West England's roofs: DESNZ counts 233,369 domestic-scale solar installations in South West England (974.1 MW) at the end of Jul 2026.
A home in Plymouth using 3,000 kWh a year, with 4 kWp of solar, adds a 10 kWh battery. Yearly savings with Plymouth's solar yield and South West England 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 | £422 | 1,082 kWh |
| Staying on a flat tariff (solar storage only) | £178 | 0 kWh |
| Same home with no solar, battery on Agile Octopus | £250 | 3,258 kWh |
| Same home with no solar and an electric car, battery on Octopus Go | £490 | 3,258 kWh |
Flux needs solar panels and Go is for electric car owners. How the model works · try your own numbers.
Backup matters more here
Ofgem’s 2024/25 performance data for National Grid Electricity Distribution’s South West licence area shows 59.01 customer interruptions per 100 customers and 50.43 minutes lost per customer, with severe-weather events stripped out. Only North Scotland comes close. For a home that loses power more often than most, a battery with backup hardware has a value the savings figures leave out: the freezer, the heating pump and the router keep running.
Backup is not automatic, though. A battery switches off with the grid unless the installation includes an emergency power socket, backup circuits or a whole-home gateway. Ask for it by name in your quote. See home battery backup.
Good solar, so solar batteries pay best
PVGIS models a 4 kWp south-facing array at 4,488 kWh a year in Plymouth, 4,262 in Truro, 4,209 in Exeter and 4,092 in Bristol, with Bournemouth at 4,479. DESNZ counts 233,369 domestic-scale solar installations in the South West at the end of July 2026, the second-highest of any region. Plenty of existing panels and strong summer surplus make the South West a good place to add a battery to solar you already have.
The battery-only case is weaker. Agile Octopus’s cheapest hours averaged 16.01p over the 30 days to 26 September 2026 in the South West area, the second-highest of the fourteen regions, so a battery charged from the grid saves less per kWh. In the model that drops a 10 kWh battery-only saving on Agile to about £250 a year. With solar and Octopus Flux (which needs panels) it is about £425.
Two operators at the eastern edge
Bristol, Somerset, Devon and Cornwall sit in National Grid’s South West area. Bournemouth and Poole, and parts of Dorset and Wiltshire including Swindon and Dorchester (both checked by postcode), are in SSEN’s Southern area, which had fewer interruptions (41.85 per 100 customers) but a similar number of minutes lost (51.18). Your postcode, not your county, decides which rates and rules apply.
Payback and size in the South West
Good solar lifts every battery case here. In the model, a 10 kWh battery with 4 kWp of solar on Flux saves about £425 a year in the South West area and £421 in the Southern area, a payback of about 12.6 years at Octopus’s £5,336 and about 21 years at the official median for the size. A 13.5 kWh Powerwall 3 at £7,999 models at about £589 a year, roughly 13.6 years.
Capacity earns in steps: about £179 a year for 5 kWh, £425 for 10 kWh and £589 for 13.5 kWh on Flux in the South West area. The battery-only case is the weak one, as above, at about £250 a year on Agile, or a 21-year payback at £5,336. Homes with an electric car on Octopus Go do much better, at about £490 a year.
Funding in the South West
The rules for England apply: 0% VAT on installed batteries until 31 March 2027; the Warm Homes Loan Scheme’s lower-interest loans of up to £15,000 for a battery; and, for eligible low-income homes, a council Warm Homes: Local Grant that can include a battery alongside solar panels. See grants and funding.
Getting quotes
If power cuts are the reason you are looking, lead with backup in your request and ask what the backup output can run. If you have solar already, give installers the inverter details. Compare home battery storage quotes on usable kWh, backup level and price per kWh.
Home batteries in South West England: questions
Are power cuts more common in the South West?
Yes. Ofgem's 2024/25 data puts National Grid Electricity Distribution's South West area at 59.01 interruptions per 100 customers and 50.43 minutes lost per customer, against GB averages of about 40 and 35. If you want backup, specify it: a battery only powers the home in a cut if backup hardware is installed.
Why is the battery-only saving lower in the South West?
Because Agile Octopus's cheapest hours were dearer here. Over the 30 days to 26 September 2026 the average of each day's cheapest three hours was 16.01p in the South West area, against 13.46p in London, so a battery charged from the grid saves less on each kWh.
Who is the network operator in Bristol, Devon and Cornwall?
National Grid Electricity Distribution (South West), which was checked by postcode for Bristol, Exeter, Plymouth and Truro. Bournemouth and Poole sit in SSEN's Southern area instead.