Smart Tariff Optimisation for Solar and Battery Homes

What a smart tariff is

A smart tariff charges different prices at different times of day. Cheap hours are often overnight, while the evening peak costs more. A battery can use that gap, because it charges when power is cheap and releases it later.

These tariffs usually need a smart meter. Some also need a compatible battery or charger. Intelligent Octopus Go, for example, needs an eligible EV or supported smart charger.

Import and export: the two sides of a tariff

Your import tariff sets what you pay for power from the grid. For example, from 1 October to 31 December 2026 the Ofgem price cap averages about 26p per kWh for electricity. The standing charge averages about 55p a day. The cap is reset each quarter and varies by region.

The next cap announcements are due on 25 November 2026 and 23 February 2027. Therefore the gap between cheap and peak rates may change. Re-check your tariff each quarter.

Your export tariff sets what you earn for spare solar power. Under the Smart Export Guarantee, suppliers must pay above 0p, although each sets its own rate. Our guide to the Smart Export Guarantee with a battery explains how the two fit together.

How a battery uses a smart tariff

On a time-of-use tariff, the battery charges from the grid in the cheap window. It then covers your home in the dearer hours. Additionally, if you have solar, it stores spare daytime power instead of exporting it all.

Some tariffs are built for batteries. For example, in October 2026, Intelligent Octopus Go charged 7.6p per kWh in its overnight window, according to Octopus. Our guide to Octopus battery storage tariffs compares the options.

Export rates compared

Export rates vary a lot between suppliers. Some pay more to their own import customers, so check the conditions. Rates move often, therefore confirm the current figure before you choose.

Rates come from each supplier's own page, read on 10 October 2026. We could not confirm EDF and E.ON Next rates, therefore we do not quote them.

Who benefits, and who does not

A smart tariff suits homes that can shift use into cheap hours. That includes homes with a battery, or an EV. Households that are home all day may gain less from time-of-use pricing.

A smart tariff is not worth chasing without a battery or flexible loads. Similarly, a switch can raise your costs if your use falls in the dear hours. Our page on home battery storage shows how storage changes that picture.

Smart tariffs for EV owners

An EV can act like a second battery. Intelligent Octopus Go, for example, offers up to 6 hours a day of smart-charging off-peak window, according to Octopus. The timing varies, so check the supplier's terms.

Government chargepoint grants of up to £500 are open to renters, flat owners and some on-street households. They run until 31 March 2027. However, home-owners with a driveway are not currently covered. Check GOV.UK before you plan around a grant.

Rules you need to know

To claim SEG payments, your system must be MCS-certified. Additionally, you need a smart meter or another meter that records half-hourly export. The scheme covers Great Britain, so Northern Ireland homes are not included.

You cannot receive SEG payments and Feed-in Tariff payments together. Chargepoints sold in Great Britain since mid-2022 must be smart, with off-peak charging set by default. For charger options, see EV charger installation.

What a smart tariff setup costs

A tariff itself is a supplier matter, so the main cost sits in the battery behind it. Which? reported in August 2026 that Ovo advertises batteries from around £2,500 and EDF Energy from £3,995. These are starting prices, so your quote may differ.

Home batteries are currently VAT-free at 0% until 31 March 2027. From 1 April 2027 the rate is due to revert to 5% under current legislation. Therefore a plan that needs a new battery should allow for that date.

We cannot promise a saving, because it depends on your tariff, your use and your system. Instead, test your own numbers. Multiply the gap between cheap and peak rates by the kWh your battery can shift a day.

Questions to ask before you switch

Ask each supplier a few plain questions before you switch. Specifically, check the cheap-rate window, any exit fee and whether the tariff needs a named device.

• What is the cheap rate, and at which hours does it apply?
• Does the tariff need a smart meter, an EV or a named charger?
• What is the standing charge, and can the rates change mid-contract?
• Does the supplier pay SEG export, and at what rate?

Rates and terms change, because suppliers update them often. Therefore read the live terms on the supplier's own page before you commit.

Setting up the system for your tariff

Your installer sets the charging window and any reserve level. They can also link the battery to your tariff, if the supplier allows it. Furthermore, a good installer shows you the app and how to change the window later.

Ask for written confirmation of which tariffs the inverter supports, since suppliers differ. Our page on smart energy monitoring explains how to track results.

If you already have panels, you can often add a battery and move to a smart tariff afterwards. Therefore read how to add a battery to existing solar first. In Cardiff, PVGIS models a 4 kWp array at about 4,167 kWh a year. See battery installers serving Cardiff for local detail.

How our matching works

Solar Base Energy is a free matching service, although we do not supply tariffs or install systems ourselves. We match you with an MCS-certified installer who can quote for your home. See also our pages on solar and battery quotes in Liverpool and battery installers in Manchester.

Sources

• Ofgem - Price cap changes, 1 October to 31 December 2026
• GOV.UK - Smart Export Guarantee
• Ofgem - Smart Export Guarantee
• Octopus Energy - Smart Export Guarantee
• Octopus Energy - Intelligent Octopus Go
• British Gas - Smart Export Guarantee