Octopus Flux Tariff: The Best Tariff for Solar + Battery?

What is Octopus Flux?

Octopus Flux is a time-of-use tariff built around a simple idea: electricity is worth different amounts at different times of day, and if you have solar panels and a battery, you can take full advantage.

Unlike Agile with its half-hourly price changes, Flux has three fixed daily periods:

Rates as of early 2026 — check Octopus for current figures.

The clever part is the export rate structure. During peak hours (4–7pm), Flux pays you roughly 22p/kWh for exports. That's when the grid needs power most, and Flux rewards you for providing it.

The daily Flux cycle

Here's how a well-optimised Flux day looks:

02:00–05:00 (off-peak): Your battery charges from the grid at ~10p/kWh. This is your backstop — cheap electricity to cover the morning before solar kicks in.

05:00–16:00 (day): Solar panels generate electricity. You use what you need, store the surplus in your battery, and export any excess at ~12p/kWh.

16:00–19:00 (peak): This is the money window. Your battery — now full from solar generation — discharges to cover your home's needs AND exports surplus to the grid at ~22p/kWh. You avoid importing at 34p/kWh and potentially earn from exports.

19:00–02:00 (day): Battery covers remaining evening needs. If it runs flat, you import at the standard day rate.

Who is Flux designed for?

Flux requires:

• Solar panels (any size, but 3kWp+ makes most sense)
• A battery (essential — Flux without a battery is pointless)
• A compatible inverter/battery system — GivEnergy, Tesla Powerwall, Solis, Fox ESS, and others work with Flux
• A SMETS2 smart meter

If you have panels but no battery, look at a standard SEG tariff for exports and a competitive fixed rate for imports. Flux's entire value proposition depends on being able to store and time-shift energy.

Real-world Flux savings

Let's model a 4kWp solar system with a 10kWh battery on Flux:

Summer day (June, sunny):

• Solar generation: 20kWh
• Household use: 10kWh
• Battery charges fully from solar (free)
• Evening peak: battery powers home (saves ~34p/kWh import) and exports 3kWh at 22p = 66p earned
• Overnight charge: 5kWh at 10p = 50p cost
• Net daily cost: roughly -16p (you earn money)

Winter day (January, overcast):

• Solar generation: 3kWh
• Household use: 12kWh
• Battery charges partially from solar, topped up overnight at 10p
• Evening peak: battery covers 3kWh of home use (saves 34p × 3 = £1.02 vs peak import)
• Remaining imports at day rate: 6kWh at 24p = £1.44
• Net daily cost: roughly £1.44

Estimated annual picture:

• Annual grid import: ~2,000 kWh at average Flux rate of ~15p (optimised) = £300
• Annual export income: ~800 kWh at average ~16p = £128
• Net annual energy cost: ~£172

Compare this to the same household on a flat 24p tariff with basic SEG at 12p:

• Import: 2,000 kWh at 24p = £480
• Export: 800 kWh at 12p = £96
• Net cost: ~£384

That's roughly £212/year better on Flux — primarily from cheaper overnight imports and premium peak exports.

Flux vs Agile: which is better?

This is the question every Octopus solar customer asks. Here's an honest comparison:

Flux wins on:

• Predictability — you know exactly what each kWh costs/earns
• Simplicity — three time periods, easy to understand
• Consistency — savings are steady year-round
• Setup — configure once, leave it running

Agile wins on:

• Ceiling potential — on the best days, Agile saves more
• Negative pricing — occasional free/paid electricity
• Flexibility — 48 different price points per day
• Export potential — Agile Outgoing can pay 30p+ per kWh during peaks

The verdict for most people: Flux. It delivers 80% of Agile's savings with 20% of the effort. Agile rewards active management and perfect automation; Flux works well with basic scheduling.

If you're the kind of person who enjoys optimising, has Home Assistant running, and doesn't mind checking prices daily, Agile can edge ahead by £50–100/year. For everyone else, Flux is the sensible choice.

GivEnergy All-in-One 5kW Hybrid Inverter

£1,200

rated power kw

5

max pv input kw

7.5

mppt channels

2

battery voltage v

48V

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Setting up Flux

1. Check compatibility — confirm your battery/inverter is on Octopus's supported list. GivEnergy and Tesla Powerwall 3 have the best integration.
2. Switch to Octopus — if you're not already a customer, switch your electricity supply. Takes 2–3 weeks.
3. Request Flux — apply through your Octopus dashboard or contact support. You'll need to provide details about your solar and battery setup.
4. Configure your battery — set up charge windows (02:00–05:00 from grid) and discharge windows (16:00–19:00 to cover peak). With GivEnergy, Octopus can push this configuration automatically.
5. Monitor and adjust — use the Octopus app to track your costs and exports. In summer, you may want to reduce overnight charging since solar will cover most needs.

GivEnergy All-in-One 9.5kWh Battery

£5,500

capacity kwh

9.5

usable capacity kwh

8.6

chemistry

LFP

cycles

6000

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Flux export payments vs SEG

One of Flux's best features is the export rate structure. Standard SEG tariffs pay a flat 3–6p/kWh regardless of when you export. Flux pays 22p/kWh during peak hours.

If you can time your exports to the 4–7pm window (which a programmed battery does automatically), you earn 4–5 times more per exported kWh than a basic SEG.

This makes Flux particularly attractive for larger solar systems that regularly produce more than the household needs. A 6kWp system with a 10kWh battery on Flux can generate meaningful export income during summer months.

Common Flux questions

Can I use Flux without a battery?

Technically yes, but it's a bad idea. Without a battery, you can't store cheap overnight electricity or time your exports for peak hours. You'd pay peak rates every evening with no way to avoid them.

Does Flux work with three-phase systems?

Yes, but check with Octopus about your specific setup. Three-phase installations are becoming more common and Flux supports them.

What happens if I use more than my battery stores?

You simply import from the grid at whatever Flux rate applies at that time. There's no penalty — you just lose the benefit of using stored cheap/free electricity.

Can I switch away if Flux doesn't suit me?

Yes, no exit fees. You can switch to Agile, Go, or a fixed tariff at any time through your Octopus dashboard.

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