Choosing the right time-of-use tariff can transform a solar-and-battery setup from a novelty into a genuine money-saving powerhouse. An energy tariff determines how much you pay for every unit of electricity you import, and what you receive for every kilowatt-hour you export. While most standard plans charge a flat rate, Octopus Energy’s smart tariffs use time-of-use pricing to reward off-peak consumption and peak exports, perfect for households with solar panels, home batteries, EVs or even heat pumps. Though rates vary regionally (London tends to be about 10 % higher than Yorkshire), the principles we explore here apply across the UK.
Quick Guide to the Right Tariff
- Default champion: Intelligent Octopus Go – unbeatable for solar + EV + battery, especially with GivEnergy and Enphase batteries.
- Plan B: Octopus Go – still super-cheap if you lack smart-API integration.
- Pure solar + storage: Flux for manual control, Agile if you relish market timing, or Intelligent Flux for seamless, API-driven optimisation.
- Heat‐pump homes: Cosy Octopus provides structured off-peak windows to minimise heating costs.
Intelligent Octopus Go
Intelligent Octopus Go guarantees a rock-bottom 7 p/kWh for six hours every night (23:30–05:30), automatically scheduling charging for your home battery or EV only when electricity is cheapest and greenest. When paired with the Fixed Outgoing tariff at 15 p/kWh, surplus solar can be exported at a premium, then rebought at 7 p if needed, turning your home battery into an arbitrage machine.
By integrating via Octopus’s Smart Charging API, compatible systems like GivEnergy, Enphase, or (soon) Tesla Powerwall can fine-tune charge-discharge cycles around your real usage profile.
Octopus Go
Octopus Go offers five hours of cheap overnight power (00:30–05:30) at 8.5 p/kWh, the original EV-focused tariff now widely used for battery charging too. You can pair it with the Fixed Outgoing Lite export tariff at 8 p/kWh, or upgrade to the 15 p Fixed Outgoing if you add smart export switching. Although the window is shorter and slightly pricier than Intelligent Go, it remains an excellent Plan B if you can’t access the smart API, especially for home batteries that can absorb cheap overnight rates and then power your home all day.
Octopus Flux
Octopus Flux is tailored for solar-and-battery households who want manual control. It features:
- Off-peak charging: 02:00–05:00 at 14.99 p/kWh import and 4.74 p/kWh export
- Standard day (05:00–16:00): 24.98 p import, 13.32 p export
- Peak export window: 16:00–19:00 at 26.6 p export (imports jump to 34.97 p).
By charging your battery in the cheap overnight slot and exporting surplus during the late-afternoon spike, you “buy cheap, sell peak”. Combined with a smart inverter and a well-sized battery, Flux can deliver significant savings compared to a fixed-rate plan.
Intelligent Octopus Flux
The “hands-free” sister tariff to Flux, Intelligent Octopus Flux matches import and export rates, so the grid becomes an infinitely large, loss-free battery. You’re charged 22.5 p/kWh for imports and paid 22.5 p for exports during the day, rising to 30 p both ways in the 16:00–19:00 window.
Octopus Energy centrally optimises thousands of batteries as a virtual power plant: it charges them when wholesale prices and carbon intensity are lowest, holds 20 % in reserve, then discharges the remaining 80 % into your home or the grid at peak times. With an eligible GivEnergy or Enphase system, thanks to Kraken API compatibility, you regain full control over overrides and firmware updates, extracting maximum value without manual scheduling.
Octopus Agile
Agile Octopus tracks wholesale prices every 30 minutes, offering both import and export rates that can dip below zero or cap at £1/kWh to protect consumers. While unpredictable, average import costs sit around 23.9 p/kWh, undercutting most fixed tariffs. Exports can be via:
- Fixed Outgoing: 15 p/kWh
- Agile Outgoing: half-hourly export matching Agile import prices.
Agile suits battery plus solar owners who actively chase plunge pricing and avoid spikes. Smart apps and automation tools can pre-fetch tomorrow’s schedule, alerting you to the next plunge or spike.
Cosy Octopus
Geared for heat pumps but useful for batteries, Cosy Octopus offers three daily “cosy” windows (04:00–07:00, 13:00–16:00, and 22:00–00:00) at 12.92 p/kWh (roughly 51 % below the regional day rate), with a 16:00–19:00 peak of 39.53 p and a standard day rate of 26.35 p. Pair it with the Fixed Outgoing tariff at 15 p/kWh to export surplus solar or stored battery energy. Three dips allow multiple charge cycles, but most batteries limit daily cycling to preserve lifespan, so Cosy is most compelling for homes with high heat-pump demand and those who value predictable windows over fully variable pricing.
Selecting the optimal tariff is the final step to unlocking maximum value from your solar panels and home battery. Our team can help you navigate regional rates, size your battery correctly, and integrate with Octopus’s smart APIs, ensuring every kilowatt works in your favour.
