Octopus Flux vs Agile: Solar Battery Tariffs in Great Britain

Key Takeaways

• Octopus Flux is a smart import and export tariff designed for homes with solar panels and a home battery, optimising charging during super off-peak hours and discharging during peak export.
• Agile Octopus offers dynamic, half-hourly electricity prices linked to wholesale markets, including potential "plunge pricing" where you are paid to consume.
• Outgoing Octopus provides dedicated export tariffs, either a flat rate (Fixed) or dynamic half-hourly rates (Agile), for electricity sent back to the grid.
• All these tariffs require a SMETS2 smart meter, or a communicating SMETS1 meter, capable of sending half-hourly readings to your supplier.

Which Octopus tariff is best for your solar and battery system?

For households in Great Britain with solar panels and a home battery, choosing the right electricity tariff can significantly impact your energy savings and earnings. Octopus Energy offers several options, primarily Flux, Agile Octopus, and their Outgoing export tariffs (Fixed and Agile), each with distinct mechanisms for managing import and export. The best choice depends on your battery's capacity, your consumption patterns, and your willingness to engage with dynamic pricing.

What is actually going on with smart tariffs?

Traditional electricity tariffs typically charge a flat rate for every unit of electricity you import and, if you have solar, might offer a flat rate for every unit you export. Smart tariffs, like those from Octopus Energy, introduce time-of-use pricing or dynamic pricing. This means the price you pay for electricity, and the price you receive for exporting it, changes throughout the day.

The goal of these tariffs is to encourage you to use electricity when it is cheaper and more abundant (often when renewable generation is high or demand is low) and to export electricity when it is most valuable to the grid (during peak demand). For homes with solar panels and a battery, this allows you to:

• Charge your battery when import prices are lowest.
• Discharge your battery to power your home when import prices are highest.
• Export stored or generated electricity to the grid when export prices are highest.

This optimisation relies on a smart meter that can record your electricity usage and export in half-hourly intervals.

Comparing Octopus Energy's Solar & Battery Tariffs

The table below outlines the key features of Octopus Flux, Agile Octopus, and the Outgoing Octopus export tariffs.

Octopus Flux: Optimised for Solar and Battery

Octopus Flux is "a smart import and export tariff designed specifically for homes with solar panels and a home battery." It operates on fixed time windows, making it predictable for battery users.

• Super Off-Peak Window (02:00 – 05:00): During these hours, you get "super cheap electricity to charge your battery when wholesale prices are lowest." This is the ideal time to recharge your battery from the grid if your solar generation has been insufficient.
• Day Rate Window (05:00 – 16:00 and 19:00 – 02:00): This is the "standard daytime rate for normal household electricity usage." Your solar panels will typically be generating during part of this window, covering your home's demand or charging your battery.
• Peak Window (16:00 – 19:00): This is the "highest import rate, and highest export rate when you get paid top rates to discharge your battery back to the grid." This three-hour window is crucial for maximising your savings and earnings. You should aim to power your home from your battery and export any surplus to the grid to take advantage of the premium export payments.

Flux "optimises battery cycles by charging at super off-peak rates and discharging during peak export windows." This structured approach can provide consistent benefits for households with suitable battery automation.

Agile Octopus: Dynamic Pricing and Plunge Rates

Agile Octopus offers "half-hourly electricity prices tied directly to wholesale market prices, updated daily at 16:00 for the following 24 hours." This tariff is for import only; you would pair it with an Outgoing tariff for your exports.

• Dynamic Pricing: Unlike Flux's fixed windows, Agile's prices fluctuate every 30 minutes. This means you need to be more proactive or have a smart battery system that can respond to these price changes.
• Plunge Pricing: A unique feature of Agile is "when wholesale energy prices drop below zero due to excess renewable generation, Agile prices can go negative, paying customers to consume electricity." This offers an opportunity to charge your battery for free, or even get paid to charge it, during periods of high renewable output.
• Peak Demand Pricing: "Prices typically spike between 16:00 and 19:00 during peak national demand." During these times, "battery systems can discharge to avoid high import prices," using stored energy instead of expensive grid electricity.
• Price Cap Protection: Agile Octopus "features a maximum price cap per kWh to protect consumers from extreme market spikes," providing a safeguard against excessively high prices.

Agile is best suited for those who can shift their electricity consumption or have automated battery systems that can react to real-time price signals.

Outgoing Octopus: Your Export Options

Outgoing Octopus tariffs are specifically for the electricity you export to the grid from your solar panels and battery. You would typically pair one of these with an import tariff like Agile Octopus or a standard fixed-rate import tariff.

• Outgoing Fixed: This option provides "a flat rate paid for every kilowatt-hour (kWh) of electricity exported to the grid, giving predictable returns for solar generation." It's a straightforward choice if you prefer stable, consistent payments for your exports.
• Outgoing Agile: This tariff offers "export payments that vary half-hourly tracking wholesale prices, allowing automated batteries to export during highest-value intervals." Similar to Agile Octopus for import, this dynamic export tariff allows you to maximise earnings by selling electricity back to the grid when demand and prices are highest.

For both Outgoing tariffs, you will need "an Export MPAN generated by your Distribution Network Operator (DNO) via your electricity supplier." Additionally, you must have "an MCS installation certificate and DNO notification (G98/G99) to validate grid compliance." These are standard requirements for connecting a generation system to the grid in Great Britain.

What you can check yourself, and what you cannot

You can check if your smart meter is a SMETS2 model or a communicating SMETS1 meter by looking at the meter itself or contacting your energy supplier. You can also verify if your solar installation has an MCS certificate and if your DNO notification (G98/G99) has been completed, typically provided by your installer.

You cannot, however, set the specific pence per kilowatt-hour rates for any of these tariffs, as these are determined by Octopus Energy and vary by region and over time. You also cannot alter the underlying network rules or the half-hourly reporting requirements for smart meters.

What the published sources do not tell you

The exact unit rates in pence per kWh for these tariffs are not published in general information. These "vary by regional DNO distribution area and change across price cap periods." Consumers must "verify exact pence/kWh values on Octopus Energy's official tariff pages" for their specific location and current period.

It is also important to note that these tariffs "apply only to properties located in Great Britain (England, Scotland, Wales)." Northern Ireland has its own separate energy market operators and arrangements, so these specific Octopus Energy tariffs are not available there.