British Gas vs Octopus vs E.ON: Best for Plug-in Solar UK

If you've just installed plug-in solar, your energy tariff determines how much each unit of self-consumed electricity is worth. Most UK households are with one of the big suppliers — British Gas, Octopus Energy, or E.ON — and the differences between them for solar owners are significant.

British Gas

Tariff options for solar: Limited. British Gas primarily offers flat-rate standard variable and fixed tariffs. There is no dedicated time-of-use tariff for solar or EV owners, and their SEG export tariff is among the lowest in the market.

Import rates: Typically at or very near the Ofgem price cap (~24p/kWh on the standard variable tariff). Fixed deals occasionally undercut this slightly.

Export payments (SEG): British Gas offers a SEG tariff, but the rate has historically been at the lower end of the market (around 3-5p/kWh). This requires MCS certification, which most plug-in solar self-installs can't provide. There is no informal arrangement for non-MCS systems.

Smart meter support: British Gas has been one of the largest installers of SMETS2 meters. If you're a British Gas customer, getting a smart meter is straightforward and free.

Verdict for solar owners: Perfectly functional but uninspiring. A British Gas flat rate works fine for basic plug-in solar self-consumption — every self-consumed kWh saves you the full import rate. But there's no tariff innovation to extract additional value from solar generation, battery storage, or load-shifting. If you're happy with a simple setup and don't plan to add battery storage, British Gas is adequate. If you want to optimise, you'll find better options elsewhere.

Octopus Energy

Tariff options for solar: The most comprehensive in the UK market. Flexible (flat-rate), Go (time-of-use with cheap overnight rate), Intelligent Go (EV-optimised), Agile (half-hourly dynamic pricing), and Flux (solar-plus-battery optimised with export payments).

Import rates: Flexible tariff is competitive with the price cap. Go's overnight rate is typically 7-9p/kWh. Agile varies half-hourly but averages competitively over a year.

Export payments (SEG): Octopus's standard SEG rate is competitive (typically 7-15p/kWh depending on the specific tariff). More importantly, Octopus has informally accepted some non-MCS plug-in solar systems for export payments — the only major supplier to do so. This isn't guaranteed, but it's worth asking.

Smart meter support: Octopus requires a SMETS2 meter for their time-of-use tariffs and actively supports installations. Their app integration with smart meter data is among the best — real-time consumption, generation, and cost overlays.

Verdict for solar owners: The clear leader for solar households. The tariff variety means there's an optimised option for every setup — from simple flat-rate to sophisticated Flux arbitrage. If you have or plan to add a battery (EcoFlow DELTA 2 or similar), the Go or Flux tariff transforms the financial case. See our full Octopus review for tariff-by-tariff analysis.

E.ON Next

Tariff options for solar: E.ON Next offers a standard variable tariff, fixed-rate deals, and the E.ON Next Drive tariff for EV owners. Drive includes a cheap overnight rate (similar concept to Octopus Go) but is restricted to households with an EV.

Import rates: Competitive with the price cap on standard variable. Fixed deals vary seasonally. The E.ON Next Drive overnight rate is typically 8-10p/kWh — slightly higher than Octopus Go but still meaningful.

Export payments (SEG): E.ON's SEG rate is mid-market (around 5-7p/kWh). MCS certification required. No informal arrangements for non-MCS systems.

Smart meter support: E.ON installs SMETS2 meters and offers basic app monitoring. Not as feature-rich as Octopus's app but functional.

Verdict for solar owners: A solid middle ground. If you're an EV owner on E.ON Next Drive, the cheap overnight rate provides similar benefits to Octopus Go — charge the car and battery cheaply, use solar during the day. Without an EV, E.ON's offering is similar to British Gas: adequate but not optimised for solar.

The Comparison Table

Which to Choose

Stay with British Gas if: you want simplicity, are satisfied with flat-rate self-consumption savings, and don't plan to add battery storage or an EV. The savings from your plug-in solar at British Gas's standard rate are still meaningful — roughly £120-170 per year for a well-placed 800W system.

Switch to Octopus if: you want to maximise the financial value of your solar system, especially if you have or plan to add battery storage. The tariff variety is unmatched. For plug-in solar owners with a battery on Octopus Go, the combined savings from solar self-consumption and overnight arbitrage can reach £200-280 per year — roughly double what you'd save on a flat-rate tariff without a battery.

Consider E.ON Next if: you're an EV owner who prefers E.ON's service and the Drive tariff. The overnight rate provides genuine value for EV charging alongside solar.

How to Switch

Switching takes 5-10 minutes online through the new supplier's website. There are no exit fees on standard variable tariffs. Most fixed tariffs have modest or no exit fees — check your current contract. The switch typically completes within 21 days, and there's no interruption to your electricity supply.

Before switching, monitor your generation for at least a month with a Tapo P110 so you know your actual self-consumption pattern. This makes tariff comparison much more meaningful — you're comparing real numbers rather than estimates.

For the full analysis of Octopus's tariff options, see our Octopus Energy review. For general tariff guidance, see our best energy tariff guide.