Time of Use Tariffs for Battery Storage: Maximise Your Savings
Time of use tariffs add £150-£300 annual savings for battery storage owners by enabling arbitrage—charging at cheap overnight rates (7-12p/kWh) and using stored energy during expensive peak periods (24-34p/kWh). Octopus Flux is the best tariff for solar + battery households, paying 24p/kWh for peak exports. Octopus Go suits EV owners, while Agile benefits those comfortable with variable pricing.
How Time of Use Tariffs Work
Standard electricity tariffs charge the same rate 24/7 (typically 22-24p/kWh). Time of use tariffs vary rates by time of day.
| Time Period | Standard Tariff | Time of Use Tariff |
|---|---|---|
| Night (02:00-05:00) | 24p/kWh | 7-12p/kWh |
| Day (05:00-16:00) | 24p/kWh | 20-28p/kWh |
| Peak (16:00-19:00) | 24p/kWh | 28-40p/kWh |
| Evening (19:00-02:00) | 24p/kWh | 20-28p/kWh |
Charge Cheap
Charge battery when electricity is cheap (overnight at 7-12p/kWh)
Discharge Peak
Use stored energy when electricity is expensive (peak hours at 28-40p/kWh)
Export Premium
Export solar surplus at premium peak rates (up to 24p/kWh on Flux)
Best Time of Use Tariffs Compared
Octopus Flux
Best for Solar + Battery
Designed specifically for solar and battery households.
| Feature | Details |
|---|---|
| Cheap import | 10p/kWh (02:00-05:00) |
| Standard import | 24p/kWh (05:00-16:00, 19:00-02:00) |
| Peak import | 34p/kWh (16:00-19:00) |
| Cheap export | 4.5p/kWh (02:00-05:00) |
| Standard export | 12p/kWh (05:00-16:00, 19:00-02:00) |
| Peak export | 24p/kWh (16:00-19:00) |
Annual savings vs standard tariff: £200-£350 (with 5kWh battery)
Why Flux is best:
- Premium 24p/kWh export during peak (others pay 4-12p)
- Cheap overnight charging (10p vs 24p)
- Designed around solar generation patterns
Requirements:
- • Octopus Energy customer
- • Smart meter (SMETS2)
- • Compatible battery system
Octopus Go
Best for EV + Battery
Designed for EV charging but works well with home batteries.
| Feature | Details |
|---|---|
| Cheap import | 9p/kWh (00:30-04:30) |
| Standard import | 28p/kWh (all other times) |
| Export rate | Variable SEG (4-12p/kWh) |
Annual savings vs standard tariff: £150-£250 (with 5kWh battery)
Best for:
- • EV owners wanting cheap overnight charging
- • Battery arbitrage (charge at 9p, avoid 28p peak)
- • Simpler rate structure than Flux
Limitations:
- • No premium export rate
- • Shorter cheap window (4 hours vs 3 hours on Flux)
Octopus Intelligent Go
Best for EV + Battery + Smart Charging
Enhanced version of Go with intelligent EV charging features.
| Feature | Details |
|---|---|
| Cheap import | 7p/kWh (23:30-05:30) |
| Standard import | 28p/kWh (all other times) |
| Smart charging | Car charges when cheapest |
| Export rate | Variable SEG |
Annual savings vs standard tariff: £200-£300 (with battery + EV)
Requires: Compatible EV or charger, Octopus app integration
Octopus Agile
Variable Pricing
Prices change every 30 minutes based on wholesale costs.
| Feature | Details |
|---|---|
| Import rates | -15p to 100p/kWh (varies) |
| Typical overnight | 5-12p/kWh |
| Typical day | 15-25p/kWh |
| Typical peak | 25-40p/kWh |
| Export (Agile Outgoing) | Tracks wholesale (avg 8-12p) |
Annual savings vs standard tariff: £100-£400 (highly variable)
Best for:
- • Risk-tolerant households
- • Those with large batteries who can avoid peaks
- • Tech-savvy users who monitor prices
Risks:
- • Prices can spike during high demand
- • Requires attention or automation
- • More complex to manage
Economy 7
Basic Time of Use
Traditional split-rate tariff available from most suppliers.
| Feature | Details |
|---|---|
| Night rate | 12-15p/kWh (7 hours overnight) |
| Day rate | 26-30p/kWh |
| Export | Standard SEG (4-5p) |
Annual savings vs standard tariff: £80-£150 (with battery)
Pros:
- • Available from most suppliers
- • Simple structure
- • No smart meter required (though recommended)
Cons:
- • Lower savings than Octopus tariffs
- • No premium export rates
- • Higher day rates than some alternatives
How to Maximise Savings with Each Tariff
Octopus Flux Strategy
| Time | Action | Rate |
|---|---|---|
| 02:00-05:00 | Charge battery from grid | 10p import |
| 05:00-16:00 | Use solar, store surplus | Free (solar) |
| 16:00-19:00 | Export from battery | 24p export |
| 16:00-19:00 | Use stored solar (avoid import) | Avoid 34p |
| 19:00-02:00 | Use remaining battery | Avoid 24p |
Daily savings example (5kWh battery):
| Action | Calculation | Value |
|---|---|---|
| Charge 5kWh overnight | 5 × 10p | -50p cost |
| Export 3kWh at peak | 3 × 24p | +72p income |
| Avoid 2kWh peak import | 2 × 34p | +68p saved |
| Net daily benefit | 90p | |
Annual benefit from Flux arbitrage: ~£330
Octopus Go Strategy
| Time | Action | Rate |
|---|---|---|
| 00:30-04:30 | Charge battery + EV | 9p import |
| 04:30-00:30 | Use battery, avoid grid | Avoid 28p |
Daily savings example (5kWh battery):
| Action | Calculation | Value |
|---|---|---|
| Charge 5kWh overnight | 5 × 9p | -45p cost |
| Avoid 5kWh day import | 5 × 28p | +£1.40 saved |
| Net daily benefit | 95p | |
Annual benefit: ~£250 (battery only, more with EV)
Agile Strategy
| Condition | Action |
|---|---|
| Price below 10p | Charge battery |
| Price above 25p | Discharge battery |
| Price negative | Charge everything possible |
| Price above 35p | Avoid all grid use |
Requires automation or careful manual management. GivEnergy batteries have built-in Agile optimisation.
Battery Settings for Time of Use Tariffs
GivEnergy Tariff Integration
GivEnergy batteries automatically optimise for popular tariffs.
Setup process:
- Open GivEnergy app
- Navigate to Settings > Tariff
- Select your tariff (Flux, Go, Agile, etc.)
- System auto-configures charge/discharge windows
Manual override options:
- Force charge during cheap periods
- Pause export if needed
- Set minimum battery reserve
Other Battery Brands
| Brand | Tariff Integration |
|---|---|
| Tesla Powerwall | Manual scheduling, some automation |
| Pylontech | Depends on inverter (Solis has modes) |
| Sigenergy | App-based scheduling |
Check your battery/inverter supports time-of-use scheduling before choosing a tariff.
Choosing the Right Tariff
Decision Matrix
| Your Situation | Best Tariff | Why |
|---|---|---|
| Solar + battery (no EV) | Flux | Premium export + cheap import |
| Solar + battery + EV | Flux or Intelligent Go | Depends on EV charging needs |
| EV + battery (no solar) | Go or Intelligent Go | Cheap overnight for both |
| Battery only (no solar, no EV) | Go or Economy 7 | Simple arbitrage |
| Large battery, risk-tolerant | Agile | Maximum potential savings |
| Want simplicity | Economy 7 | Predictable, widely available |
Switching Tariffs
You can switch between Octopus tariffs relatively easily:
- No exit fees on most Octopus tariffs
- Switch takes effect within days
- Try different tariffs to find what works
Recommendation: Start with Flux if you have solar + battery. It's designed for your setup and offers the best export rates.
Annual Savings Comparison
5kWh Battery with 10-Panel Solar
| Tariff | Self-Consumption | Arbitrage | Total |
|---|---|---|---|
| Standard variable | £350 | £0 | £350 |
| Economy 7 | £350 | £80 | £430 |
| Octopus Go | £350 | £150 | £500 |
| Octopus Flux | £350 | £200 | £550 |
| Octopus Agile | £350 | £150-£250 | £500-£600 |
Impact on Battery Payback
| Configuration | Standard Tariff | With Flux |
|---|---|---|
| Battery cost (retrofit) | £3,500 | £3,500 |
| Annual savings | £350 | £550 |
| Payback period | 10 years | 6.4 years |
Time of use tariffs reduce battery payback by 30-40%.
Potential Downsides
Complexity
Time of use tariffs require:
- Smart meter
- Understanding of rate windows
- Battery configuration (usually one-time)
- Monitoring (optional but helpful)
Peak Rate Risk
If your battery runs flat before peak ends, you pay premium rates:
- Flux peak: 34p/kWh (vs 24p standard)
- Go peak: 28p/kWh
Ensure battery capacity matches your peak usage, or set minimum reserve levels.
Lifestyle Constraints
Some households find rate windows restrictive:
- Doing laundry at 2am to use cheap rates
- Avoiding cooking during peak times
- Monitoring app for price alerts (Agile)
With battery storage, these constraints are minimal—the battery handles optimisation automatically.
Frequently Asked Questions
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