Battery Storage and Time-of-Use Tariffs: Save Money 24/7

The Arbitrage Opportunity

Battery storage paired with time-of-use tariffs creates a profitable energy arbitrage strategy. Import electricity at 7p/kWh overnight, store it in your battery, and export during the 4-7pm peak at 26-30p/kWh — generating approximately 19p/kWh profit per cycle. With a 10kWh battery completing daily cycles, this adds £300-£600 per year on top of solar self-consumption savings.

Octopus Intelligent Flux pays up to 30.31p/kWh during peak exports, the highest rate available. Octopus Agile offers variable pricing that occasionally goes negative (you're paid to consume). The strategy requires a compatible smart battery with grid-trading capability — Tesla Powerwall 3 and Fox ESS both support this.

Self-Consumption vs Export Strategy

Without a battery, solar self-consumption typically reaches 35-50%. Adding a battery pushes this to 70-85%. At current electricity prices of approximately 24.5p/kWh, every unit you store and use saves more than exporting at most flat SEG rates. The optimal strategy combines high self-consumption with strategic peak-time exports: use solar during the day, store surplus for evening use, and only export when peak pricing exceeds your avoided import cost.