Time-of-use electricity tariffs can dramatically cut your energy bills when paired with battery storage. Here are the best tariffs available and how to make the most of them.
What Is a Time-of-Use Tariff?
A time-of-use (ToU) tariff charges different electricity rates depending on the time of day. Instead of paying a flat 24p/kWh around the clock, you pay a much cheaper off-peak rate (as low as 7p/kWh) during certain hours — typically overnight — and a higher rate during peak daytime hours. Without a battery, these tariffs are mainly useful if you can shift your usage to off-peak hours (running the dishwasher overnight, for example). With a battery, you can charge at the cheapest rate and discharge during the expensive hours, saving money automatically every day.
Octopus Go and Intelligent Go
Octopus Go offers a 4-hour off-peak window (typically 12:30am-4:30am) at around 7p/kWh, with a standard peak rate of around 24-25p/kWh. This is one of the most popular tariffs for battery storage owners. Intelligent Octopus Go is designed for EV owners and offers a longer 6-hour off-peak window (11:30pm-5:30am) at a similar rate. Both tariffs work brilliantly with battery storage — charge your battery at 7p during the off-peak window and avoid buying electricity at 24p+ for the rest of the day. The daily saving of around 17p per kWh adds up quickly across a 10kWh battery.
Octopus Flux
Octopus Flux is designed specifically for solar and battery owners. It offers three rate bands: a cheap overnight rate for charging, a mid-rate during the day, and a premium export rate during the evening peak (4pm-7pm) when you are paid more for electricity you export to the grid. With a well-configured solar and battery system, you can charge your battery overnight cheaply, use solar during the day, and export stored energy during the premium evening window. This tariff maximises the value of both your solar panels and battery storage.
Economy 7 and Economy 10
Economy 7 and Economy 10 are older time-of-use tariffs that have been available for decades. Economy 7 offers 7 hours of off-peak electricity (usually overnight), while Economy 10 offers 10 off-peak hours split across the day and night. While the off-peak rates are competitive, the peak rates tend to be higher than standard tariffs. These tariffs were originally designed for storage heaters, but they work with battery storage too. However, newer tariffs like Octopus Go generally offer better value for battery owners.
How Much Can You Save?
The savings depend on your battery size and daily usage. With a 10kWh battery on Octopus Go, you could save around £1.70 per day (10kWh x 17p difference between peak and off-peak). Over a year, that is over £600 in savings from the battery alone — without solar panels. Add solar panels and the savings increase further, as you are generating free electricity during the day and only topping up from the cheap overnight rate when needed.
Choosing the Right Tariff for Your Setup
If you have battery storage only (no solar), Octopus Go is typically the best choice for straightforward overnight charging and daytime savings. If you have solar and battery, Octopus Flux can maximise both self-consumption and export value. If you also have an EV, Intelligent Octopus Go combines cheap car charging with battery storage charging in one tariff. At GM Electrical Services, we help our customers understand which tariff best suits their system and configure their battery to charge and discharge at the optimal times.
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