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Guide · New Solar Owner · Tariff Selection

Choosing the right electricity tariff Flat-rate, time-of-use, Agile, and export rates compared

The wrong tariff can cost a solar and battery household £200–£500 per year in missed savings. The right one turns your system into a genuine money-making machine. This guide walks you through every option and shows you how to pick the tariff that matches your setup.
I have a batterySolar only — no battery
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  • Rates updated March 2026
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Written by · Independent Solar Engineer Last updated

The Basics

Your tariff has two sides — and both matter

When you have solar panels, your electricity costs split into two separate flows: what you buy from the grid (import) and what you sell back to it (export). These can be with different suppliers, at different rates, and optimising both is how you get the best financial return from your system.

Import tariff — what you pay

This is your standard electricity bill. Every kWh your home draws from the grid is charged at your import rate. Solar reduces this by powering your home directly during the day, and a battery extends that coverage into the evening. The less you import, the lower your bill — but the rate you pay for what you do import still matters.

Export tariff — what you earn

When your panels generate more than your home and battery can use, the surplus flows to the grid. With an export tariff, you get paid for every kWh you send back. Without one, that energy is given away for free. Export rates range from 3p to 15p per kWh depending on your tariff and supplier.

The financial impact of getting both right
Typical 4kW system, flat-rate tariff, no export tariff saves ~£500/yr
Same system, flat-rate tariff + SEG export at 15p saves ~£700/yr
Same system + 9.5kWh battery, time-of-use + premium export saves ~£1,000/yr
Important: The figures above are illustrative based on early 2026 rates and a south-facing system in northern England. Your actual savings depend on system size, orientation, battery capacity, consumption patterns, and the specific tariff rates at the time. The principle — optimise both import and export — is consistent regardless of the exact numbers.
With a Battery

Best tariff options if you have a battery

A battery changes everything about tariff selection. It lets you buy electricity when it is cheapest and use it when it is most expensive — effectively arbitraging the price difference. Time-of-use tariffs are designed for exactly this, and they almost always outperform flat-rate tariffs when a battery is involved.

Octopus Flux — best all-round for solar + battery

Octopus Flux is purpose-built for solar and battery systems. It has three rate periods: cheap overnight (02:00–05:00, around 12p/kWh), standard daytime, and premium peak export (16:00–19:00, up to 25p/kWh). The strategy: charge the battery at 12p overnight, let solar top it up during the day, then export stored energy at 25p during the peak window.

The maths: Charge 9.5kWh at 12p = £1.14. Export at 25p during peak = £2.38. Net gain per cycle: £1.24. Over a year, that battery arbitrage alone is worth roughly £450 — before you count the free solar self-consumption during the day.
Octopus Go / Intelligent Octopus Go — best if you also have an EV

Octopus Go offers a cheap overnight window at around 7p/kWh with a standard daytime rate. The window itself is currently 00:30–05:30, five hours. Legacy and regional variants exist, including the older four-hour 00:30–04:30, so check your own tariff agreement for the hours you actually get. Intelligent Octopus Go is similar but designed for EV owners with compatible chargers — it can extend the cheap window if your car needs more charge. Both work well for batteries: charge overnight at 7p and use stored energy during the day. The export rate is typically lower than Flux's peak export, so Go suits homes that self-consume most of their energy rather than export.

Octopus Agile — highest potential, most complex

Agile has half-hourly pricing that changes daily based on wholesale costs. Prices can go negative (you get paid to use electricity) and can spike above 100p/kWh during peak demand. It rewards active management — charging the battery during cheap or negative periods and avoiding import during spikes. Agile works best with home automation platforms that can respond to price signals automatically. Without automation, managing Agile manually is time-consuming and risky if you miss a price spike.

Which one? For most solar + battery households, Octopus Flux is the simplest path to the best return. If you also have an EV, Octopus Go or Intelligent Octopus Go may work out better. Agile is for technically confident owners who want to maximise every penny and are comfortable with price volatility. All three require a smart meter.
Solar Only

Best tariff options without a battery

Without a battery, you cannot store cheap overnight electricity, so the main advantage of time-of-use tariffs disappears. Your strategy is simpler: keep your import rate low, maximise self-consumption during solar hours, and make sure you have a competitive export rate for the surplus.

Flat-rate import + competitive SEG export — simplest and usually best

Find the best flat-rate import deal you can, then pair it with the highest-paying Smart Export Guarantee rate available. This combination is simple, predictable, and requires no schedule configuration. You save the full import rate on every kWh you self-consume and earn the export rate on every kWh you send to the grid. No smart meter is strictly required for the import tariff, but you do need one for export payments.

Time-of-use can still work — but the benefit is smaller

Without a battery, you cannot take advantage of cheap overnight rates because you have nothing to store the energy in. However, if your household naturally uses a lot of electricity overnight (immersion heater on a timer, EV charging, storage heaters), a time-of-use tariff may still save money on that specific overnight usage. The solar benefit during the day is the same regardless of your import tariff type — it offsets whatever rate you would otherwise pay.

Thinking about adding a battery? If you are considering adding a battery to your existing solar system, factor the tariff savings into your payback calculation. A battery that costs £5,000 but unlocks £400–£500 per year in tariff arbitrage pays for itself in 10–12 years from tariff savings alone — before counting the self-consumption improvement.
Comparison

Tariff comparison at a glance

Approximate rates as of early 2026. All tariffs require a smart meter except standard flat-rate. Rates change — always check current pricing with the supplier before switching.

Tariff Cheap rate Day rate Export rate Best for
Octopus Flux ~12p ~24p ~25p peak Solar + battery (export focused)
Octopus Go ~7p ~24p ~15p Battery + EV (self-consumption focused)
Octopus Agile Variable Variable Variable Tech-savvy owners with automation
Flat rate + SEG — ~24p 4–15p Solar only (no battery)
Rates are indicative. Tariff rates change frequently. The structure — cheap overnight, standard day, premium peak — is consistent across time-of-use tariffs, but the exact pence-per-kWh figures will differ from what is shown here. Always check with the supplier for the current rates in your region.
Export Rates

Export tariffs — getting paid for your surplus

The Smart Export Guarantee (SEG) is the UK scheme that pays you for solar electricity exported to the grid. It replaced the old Feed-in Tariff for new installations. If you do not have an export tariff, every kWh you export earns nothing — this is surprisingly common and one of the easiest fixes for a new solar owner.

Fixed-rate SEG — predictable, simple

A fixed-rate SEG tariff pays the same price per kWh regardless of when you export. Rates range from 3p to 15p depending on the supplier. Higher rates sometimes come with conditions (minimum export volume, annual review). Fixed SEG is the safest option if you want predictable income from your exports with no management required.

Variable / Agile export — higher potential, less predictable

Some suppliers offer variable export rates that track wholesale prices. When wholesale prices are high (winter evenings, calm days with low wind), export rates can spike well above fixed SEG rates. When wholesale is low, the rate drops. Agile Outgoing from Octopus is the best-known example. This works well if you have a battery and can time your exports to high-price periods.

Bundled export (Flux, Go) — built into the import tariff

Some time-of-use tariffs include export rates as part of the package. Octopus Flux includes a premium peak export rate (up to 25p) during the 16:00–19:00 window. This is often better than any standalone SEG rate, but it means your import and export are tied to the same supplier and tariff.

What you need: An MCS-certified solar installation and a smart meter (or approved export meter) that records half-hourly export data. If you do not have a smart meter, contact your energy supplier to book a free installation. Once installed, you can sign up for any SEG tariff within a few days.
Making the Switch

How to switch your tariff

Switching is straightforward, but there are a few things to check and configure after the switch to make sure your system takes full advantage of the new rates.

Step by step
1.Check you have a smart meter. Time-of-use tariffs require half-hourly metering. If you do not have a smart meter, book a free installation through your energy supplier — this usually takes 2–4 weeks.
2.Gather your monitoring data. Check your monitoring portal for your average monthly generation, import, export, and self-consumption over the last 3–6 months. You will need these figures to model which tariff saves the most.
3.Compare tariffs using your actual data. Plug your real figures into the comparison: (import volume × import rate) minus (export volume × export rate) for each tariff option. The tariff with the lowest net annual cost wins. Do not rely on generic comparison sites — they rarely factor in solar generation.
4.Sign up and wait for the switch. Apply through the supplier's website. The switch typically takes 2–3 weeks. You will receive confirmation when the new tariff is live.
5.Reconfigure your battery schedule. This is the step most people forget. If you have moved to a time-of-use tariff, set your battery's timed charge window to match the new cheap-rate hours. If you have moved from one time-of-use tariff to another, the cheap-rate hours may be different. Check the Flux guide or your tariff documentation for the exact windows, and update your inverter settings accordingly.
After switching — check these

In the first week after your tariff switches, check your monitoring data daily. Confirm: battery is charging during the new cheap window, battery is discharging or exporting during peak hours (if applicable), your import and export figures look correct on your smart meter, and no error codes have appeared on your inverter.

BST clock change warning

When clocks change in March and October, some inverters adjust schedules automatically and some do not. If yours doesn't, your charge window shifts by an hour — potentially missing the cheap rate entirely. Check and adjust your schedule twice a year. Our Flux guide covers the fix for each brand.

Common mistake after switching: Moving to a time-of-use tariff but leaving the battery in default self-consumption mode without a timed charge window. The result: the battery only charges from solar, never takes advantage of the cheap overnight rate, and you effectively pay the standard daytime rate for all your grid import. Always configure timed charge after a tariff switch.
Related Reading

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Maximising Your System

Self-consumption, battery scheduling, load shifting, and the common mistakes that cost new owners £200–£500 per year.

See Maximising Your System →
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Smart Export Guarantee Explained

How SEG works, current rates, eligibility, and how to sign up with the best-paying supplier.

See Smart Export Guarantee Explained →
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Octopus Flux with Solar

Full setup guide for Flux's three-period tariff, including brand-specific inverter configuration and BST fixes.

See Octopus Flux with Solar →
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How Battery Storage Works

Battery chemistry, BMS, charge cycles, degradation — the technical foundation for understanding battery tariff strategies.

See How Battery Storage Works →
Upgrade
Add a Battery to Existing Solar

If you have solar but no battery, adding one unlocks time-of-use tariff savings and dramatically improves self-consumption.

Add a battery to existing solar →
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What to check monthly, quarterly, and annually to keep your system performing at its best.

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FAQ

Frequently asked questions

A competitive flat-rate import tariff combined with a good Smart Export Guarantee rate is usually the best option. You save the full import rate on self-consumed solar and earn the export rate on surplus. Time-of-use offers less benefit without a battery because you cannot store cheap overnight electricity. Focus on maximising self-consumption by shifting heavy appliances to solar hours.
A time-of-use tariff almost always saves more. Octopus Flux offers cheap overnight rates to charge the battery and premium export rates during peak hours. The battery charges cheaply at night, solar tops it up during the day, and stored energy is used or exported during expensive peak hours. The net gain from battery cycling can be 15–22p per kWh, adding up to £200–£400 per year on a typical 9.5kWh battery — on top of solar self-consumption savings.
Yes. Your import tariff and your SEG export tariff do not need to be with the same supplier. You can shop for the best import deal and the best export deal independently. However, bundled tariffs like Octopus Flux combine import and export in a single product — and the combined benefit is often better than mixing two separate tariffs. Always calculate total annual cost (import spend minus export earnings) rather than comparing either rate in isolation.
Octopus Agile uses half-hourly pricing that changes daily based on wholesale costs. Prices can go negative (you get paid to consume) and can spike above 100p during peak demand. It works well for technically engaged owners who can automate battery charging around price signals. The risk is price spikes during high-demand periods, so a battery with enough capacity to cover peak hours is essential. Agile is not the simplest option and requires more active management than Flux or Go.
You need a smart meter recording half-hourly data (SMETS2 or enrolled SMETS1). If you do not have one, book a free installation through your supplier. Once installed and recording, sign up with the relevant time-of-use supplier. The switch takes 2–3 weeks. After switching, reconfigure your battery charge schedule to match the new tariff's cheap-rate window — this is the step most people miss.
At least once a year, or whenever your circumstances change — adding a battery, getting an EV, or your fixed-rate deal ending. Check your monitoring data for actual import, export, and self-consumption figures, then model those against alternative tariffs. Spring is a good time to review — you have a full winter's data and can see how your system performs in low-generation months. Energy comparison sites rarely factor in solar, so manual calculation is usually needed.
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