Time of use (ToU) tariffs charge varying rates for electricity based on the time of day. For UK solar panel owners in 2026, pairing a ToU tariff with a solar battery allows you to buy grid energy at night for around 7p/kWh, use free solar power during the day, and sell excess energy back to the grid during evening peaks for 20p/kWh or more.
Solar panels have been a reliable way to cut electricity bills for years, but the way we buy and sell energy is changing. If you just stick to a standard flat-rate energy tariff, you are missing out on a significant chunk of the financial return your solar system can generate.
Working out which energy tariff makes the most financial sense is genuinely tricky. You need to map out not just your solar generation, but exactly when you use power, what you pay to import it, and what you get paid to export it.
This guide cuts through the confusion. We will look at exactly how time of use tariffs work alongside solar panels, which UK energy providers offer the best deals in 2026, and how a home battery changes the maths entirely.
How do time of use tariffs actually work with solar panels?
A time of use tariff simply means the price you pay for electricity goes up and down depending on the time of day. Unlike a flat rate tariff where you pay around 24p per kWh no matter when you boil the kettle, ToU tariffs reward you for using energy when grid demand is low, and penalise you when grid demand is high.
For a solar panel owner, these tariffs work on two fronts: you pay a variable rate for the electricity you import from the grid, and you get paid a variable rate for the electricity you export back to it.
| Period | Typical import rate | Why |
|---|---|---|
| Off-peak (night) | 7p–12p | The grid has excess power, so suppliers want you to use it. |
| Standard (daytime) | 20p–28p | Rates sit around normal levels. |
| Peak (4pm–7pm) | 30p–45p | Everyone gets home and starts cooking, so prices spike. |
This is where solar panels paired with a smart tariff become highly effective. You can avoid those expensive daytime and evening rates by using the free power your panels generate. More importantly, if you have excess solar power in the late afternoon, you can sell it back to the grid during the 4pm to 7pm peak, earning a premium rate.
What are the best time of use tariffs in the UK for 2026?
Octopus Energy currently dominates the smart tariff market in the UK, offering several highly integrated options for solar owners. Which one you choose depends entirely on the hardware you have installed at home.
| Tariff | Best for | Headline detail |
|---|---|---|
| Octopus Flux | Standard solar + battery | Three fixed periods; ~14p import 2–5am; 25–32p peak export |
| Octopus Agile | Highly engaged / smart homes | Half-hourly pricing; can go negative, can spike toward £1 |
| Intelligent Octopus Go | EV owners | Large overnight charging window at ~7p/kWh |
| Octopus Cosy | Heat pump owners | Three cheap daily windows: 4-7am, 1-4pm, 10pm-midnight |
Octopus Flux is, on balance, the best choice for a standard solar and battery setup. It offers a predictable three-period schedule. You get cheap import rates between 2am and 5am (around 14p/kWh), standard rates during the day, and peak rates between 4pm and 7pm. The major benefit is that you also get paid a peak export rate of around 25 to 32p per kWh if you send energy to the grid between 4pm and 7pm.
Flux comes in two forms. Standard Flux lets you set your own charge and export schedule, while Intelligent Octopus Flux automates it for you and usually earns more – but it only works with a compatible battery brand such as Tesla Powerwall, GivEnergy, FoxESS, SolarEdge, Enphase or Sigenergy. Both the rates and the availability of these tariffs change with the wholesale market, so check the live Octopus page before switching.
Octopus Agile is for the highly engaged user. Instead of fixed periods, the price changes every half hour based on wholesale energy costs. Rates can drop to negative numbers – meaning you actually get paid to use electricity – but they can also spike up to £1 per kWh during peak times. Choose Agile if you have a home automation system and a battery that can respond dynamically to price drops.
If you have specific high-draw equipment, you should look at dedicated tariffs. Intelligent Octopus Go is the top choice if you have an electric vehicle (EV), offering a massive overnight charging window at roughly 7p/kWh. Octopus Cosy is designed for heat pump owners, offering three distinct cheap windows (typically 4-7am, 1-4pm and 10pm to midnight) to warm your home.
The downside to all these tariffs is that you are heavily exposed to peak pricing. If you consistently need to run your oven, washing machine, and tumble dryer at 5:30pm, and your solar isn’t covering it, your bills will increase.
Do you really need a battery for a time of use tariff?
To get the real financial benefit of a time of use tariff, a solar battery is essentially mandatory.
Without a battery, you cannot store that cheap 7p overnight energy to use during the morning rush. More importantly, you cannot save your midday solar generation to sell back to the grid at the lucrative 4pm to 7pm peak rate. You just export it as it generates, missing the highest prices.
Buy cheap energy from the grid at roughly 7p/kWh to charge your battery to 50-80%.
Use that stored cheap energy for breakfast and showers, avoiding the 24p/kWh grid rate.
Let your solar panels run the house and fill the rest of the battery for free.
Force your battery to export its stored energy to the grid, earning you 25 to 32p per kWh.
Use whatever is left in the battery to avoid paying 35p+ peak grid rates.
If you only have solar panels without a battery, a ToU tariff might still make sense if you can program your EV to charge overnight, or if you run an immersion heater. But for the average household, a flat tariff is usually safer and simpler.
How much money can you save with a smart tariff and solar?
When you combine solar, a battery, and a smart tariff like Octopus Flux, the savings become highly attractive. You are essentially practising energy arbitrage: buying low and selling high.
Net annual cost: 3,000 kWh used, 1,500 kWh exported
Net annual cost – a £330 saving from changing how you buy and sell
According to 2026 market data, a typical home using 3,000 kWh a year and exporting 1,500 kWh will see a net annual cost of around £570 on a standard flat tariff. If that same home switches to a ToU tariff and optimises their battery, that net cost drops to roughly £240 per year – a saving of £330 purely from changing how they buy and sell.
For heavier users, the gap widens. A home with a 4kW solar array, a 10kWh battery, and an EV could save up to £600 a year by switching from a flat rate to a ToU tariff.
The consideration here is battery degradation. Cycling your battery from the grid every night adds wear and tear. Most modern lithium iron phosphate (LiFePO4) batteries easily handle 6,000 to 10,000 cycles, meaning they will outlast their 10-year warranties even with heavy ToU use, but it is a factor worth keeping in mind.
Is a time of use tariff the right choice for your home?
You have a smart meter, a solar battery, and a predictable energy routine.
You can automate your battery to charge overnight and discharge during the peak evening window – in which case a tariff like Octopus Flux should be at the top of your list.
Your home relies entirely on grid power between 4pm and 7pm, or you do not have a battery to bridge that expensive gap.
You want simplicity and never want to look at an energy app – in which case stick to a good fixed flat rate.
What to do next to start saving on your energy bills
If you already have solar panels and a battery, check your inverter’s app to ensure it supports scheduled charging and forced export. Once confirmed, contact your energy supplier to request a switch to a smart export tariff – Octopus Flux is the standout option for solar-and-battery homes whenever it is open to new sign-ups.
Frequently asked questions about solar and smart tariffs
What equipment do I need to use a time of use tariff?
You must have a functioning smart meter capable of sending half-hourly readings to your energy supplier. To actually make money on the tariff, you also need a solar array, a compatible hybrid inverter, and a home battery system (like a GivEnergy or Tesla Powerwall) connected to an active internet connection.
Can I lose money on a time of use tariff?
Yes. If you do not have a battery to cover your home’s energy usage between 4pm and 7pm, you will be forced to buy electricity from the grid at peak rates (often 35p to 45p per kWh). If you use a lot of power during this window, it will wipe out the savings you made during the cheap overnight periods.
How do I switch my solar setup to an export tariff?
First, ensure you have an active Microgeneration Certification Scheme (MCS) certificate for your solar installation. Then, apply through your chosen energy supplier’s website. They will verify your smart meter connection and switch your import and export accounts to the new tariff, which typically takes two to three weeks.
Is Octopus Agile better than Octopus Flux?
Choose Octopus Flux if you want predictable, guaranteed rates that make it easy to program your battery once and forget about it. Choose Octopus Agile if you have a smart home setup that can automatically trigger high-load appliances (like EV chargers or heat pumps) whenever wholesale prices drop, as this requires active daily management.
