Best Energy Tariff for Plug-in Solar Owners UK 2026

Your plug-in solar panels generate free electricity. But how much that electricity is worth to you depends heavily on your energy tariff. A system that saves £120 a year on a flat-rate tariff might save £180+ on a time-of-use tariff — and the difference is purely down to which deal you're on.

With plug-in solar now legal in the UK and uptake accelerating, energy suppliers are starting to compete for solar households. Here's how to choose the right tariff for your situation.

How Tariffs Affect Solar Value

Plug-in solar saves you money in one primary way: by reducing how much grid electricity you import. Every kilowatt-hour your panels generate and you consume at home is one fewer kWh you pay your supplier for.

The value of that self-consumed kWh is whatever your import rate is. On a standard flat-rate tariff at 24p/kWh, each self-consumed unit saves 24p. On a time-of-use tariff where the daytime rate is 30p/kWh, each unit saves 30p. On an off-peak tariff where daytime is only 15p/kWh, each unit saves just 15p.

This is why tariff choice matters: the same solar generation is worth double on a tariff with high daytime rates compared to one with cheap daytime rates.

The Three Tariff Types That Matter

1. Flat-Rate (Standard Variable or Fixed)

Most UK households are on a flat-rate tariff — you pay the same price per kWh regardless of when you use electricity. As of spring 2026, the Ofgem price cap sets the default rate at around 24p/kWh.

For plug-in solar owners: flat-rate is simple and decent. Every self-consumed kWh saves you the full rate. There's no complexity and no need to shift consumption to particular hours. For households that don't want to think about timing, flat-rate is perfectly fine.

Downside: you don't get any extra value from solar generation timing, and you pay the same rate in the evening (when you're drawing from the grid) as you would during the day (when you're generating). If you add battery storage later, a flat-rate tariff limits the battery's value because there's no price difference to arbitrage.

2. Time-of-Use (Octopus Go, Octopus Intelligent, E.ON Next Drive)

Time-of-use (ToU) tariffs charge different rates at different times of day. The typical pattern: cheap overnight rates (as low as 7-12p/kWh for 4-6 hours), and a higher daytime/evening rate (often 25-35p/kWh).

For plug-in solar owners: ToU tariffs are where the maths gets interesting. Your solar generates electricity during the day — exactly when the ToU rate is highest. Every self-consumed unit offsets the expensive daytime rate, and you can shift heavy loads (washing machine, dishwasher, EV charging) to the cheap overnight period.

The numbers: if your daytime rate is 30p/kWh and your overnight rate is 8p/kWh, each self-consumed solar kWh saves 30p, and each kWh of overnight charging costs only 8p. The spread between these rates is the value proposition.

Who benefits most: households with an EV (Octopus Intelligent Go is designed specifically for this), households with battery storage (charge from cheap overnight, use during the day when solar isn't enough), and households who are disciplined about running appliances overnight.

3. Dynamic/Agile (Octopus Agile)

Agile tariffs change price every 30 minutes based on wholesale electricity costs. In spring and summer, daytime prices sometimes go negative — meaning you're paid to consume electricity.

For plug-in solar owners: Agile is high-reward but high-complexity. On sunny days when wholesale prices drop, your solar self-consumption is displacing cheap (or free) grid electricity, which reduces the savings. But on cloudy winter evenings when prices spike to 40-60p/kWh, the battery-plus-solar combination becomes extremely valuable.

Who benefits most: technically engaged households who actively monitor pricing and have battery storage. Not recommended for hands-off households. See our Octopus Agile deep dive for the full picture.

The Best Tariff by Household Type

Home during the day, no battery, no EV

Recommendation: flat-rate or standard fixed. Your solar generation and consumption are naturally aligned. You're already capturing most of what you generate. A ToU tariff won't help much because your consumption pattern doesn't shift significantly.

Out during the day, no battery, no EV

Recommendation: time-of-use (Octopus Go or similar). You're exporting most of your solar generation unpaid. Shift your heavy loads to cheap overnight hours and you'll save on grid import even though you're not capturing daytime solar. Your daytime rate will be higher, but you're not importing much during the day.

Any pattern, with battery storage

Recommendation: time-of-use (Octopus Go or Flux). Battery changes everything. Charge from solar during the day, use stored electricity in the evening, and charge from cheap overnight grid when the battery is empty. The spread between overnight import and daytime self-consumption is your total benefit. The EcoFlow DELTA 2 or Anker SOLIX C1000 can store enough to cover 2-4 hours of evening consumption.

EV owner

Recommendation: Octopus Intelligent Go. This is specifically designed for EV households. You get cheap overnight electricity for the car and the house, and your solar offsets daytime consumption. If you charge the car overnight at 7p/kWh and your daytime rate is 28p/kWh, the combination with solar is extremely effective.

Export Payments: Do They Change the Calculation?

If you can access the Smart Export Guarantee (SEG), your exported electricity has some value — typically 4-15p/kWh depending on the supplier and tariff. This makes flat-rate slightly more attractive relative to ToU, because export value partially compensates for daytime generation you don't consume.

However, most plug-in solar self-installs can't access SEG due to the MCS certification requirement. See our SEG explainer for the current position.

How to Switch

Switching energy supplier takes 5-10 minutes online and usually completes within 21 days. There are no exit fees on standard variable tariffs, and most fixed tariffs now have modest or no exit fees.

Before switching:

1. Check your current tariff — log into your supplier's app or website to see your exact unit rates and standing charge.
2. Estimate your solar self-consumption — a Tapo P110 on the inverter output tracks daily generation. Subtract your estimated daytime consumption to estimate exports.
3. Compare tariffs — use a comparison service to find the best rate for your consumption profile. When comparing, factor in the value of self-consumed solar at different tariff rates, not just the headline price.
4. Consider the switching bonus — Octopus Energy's referral programme typically offers a £50 credit for new customers switching from another supplier. Similar incentives are available from other suppliers.

Monitoring Your Tariff Value

Once you've switched, track whether the tariff is delivering the expected savings. The Emporia Vue 3 shows real-time import and export with cost overlays, making it easy to see how much your solar is saving against your specific tariff rates.

If you find that your self-consumption is lower than expected — meaning more solar is being exported unpaid — revisit the battery storage question. The financial case for a battery improves significantly when you can see exactly how much generation you're losing to export.

Our Recommendation

For most UK plug-in solar owners without a battery or EV, a competitive flat-rate fixed tariff is the simplest and most effective choice. The savings from solar self-consumption at 24p/kWh are meaningful, and there's no complexity.

For households with battery storage, an EV, or a willingness to manage timing, Octopus Go or Flux offers the best combined value. The cheap overnight rate dramatically reduces your grid costs, and the higher daytime rate makes every self-consumed solar kWh worth more.

Whichever tariff you choose, the key insight is that your energy deal is as important as your panel orientation. A poorly chosen tariff can halve the financial value of a perfectly installed system.

For tariff-specific deep dives, see our guides on Octopus Agile, Octopus Flux, and SEG export payments.