Smart Meters and Time-of-Use Tariffs: Getting More from Your Solar Panels

Time-of-use tariffs pay you more for exporting during peak hours and charge less overnight. Here's how they work with plug-in solar and a smart meter.

Why Time-of-Use Tariffs Suit Solar Owners

A standard flat-rate tariff charges you the same per kWh regardless of when you use electricity. A time-of-use (ToU) tariff varies the rate by time of day — typically offering cheap overnight rates, standard daytime rates, and expensive peak evening rates.

For plug-in solar owners, this creates a double opportunity:

Your panels generate during the day when rates are standard — offsetting mid-price import
You export during the day when the grid is relatively well-supplied — but some tariffs still pay decent rates
You can shift heavy loads to cheap overnight periods using a timer

A SMETS2 smart meter with half-hourly settlement is required for ToU tariffs. Without it, your supplier can't bill you at the correct rates.

Octopus Flux: The Solar-Specific Tariff

Octopus Flux is designed explicitly for solar and battery owners. It has three time bands:

Off-peak (02:00–05:00) — cheapest import rate; charge your battery here
Day (05:00–16:00 and 19:00–02:00) — standard rate
Peak (16:00–19:00) — highest import rate, but also highest export rate

The peak export rate is the key feature. If your panels are still generating at 16:00–17:00 (common in summer), or your battery discharges stored solar during peak, you earn the most.

For plug-in solar without a battery, the benefit is mainly avoiding peak import rather than earning peak export — your panels produce less in the late afternoon, and a 400–800W system may not export much during peak hours.

Octopus Go: For EV Owners with Solar

Octopus Go gives you a very cheap overnight window (typically 00:30–05:30) and a flat rate the rest of the day. If you have an EV, charge it overnight at the cheap rate and use your solar during the day for household loads. The smart meter tracks which kWh fall in which time band.

Agile Octopus: Advanced, Variable Pricing

Agile charges a different rate for every half-hour slot, tracking wholesale prices. On sunny days when solar farms are flooding the grid, daytime prices can drop very low (occasionally negative). On dark winter evenings, prices spike.

This tariff rewards solar owners who are actively engaged — watching prices and shifting loads accordingly. The smart meter is essential here, as billing depends entirely on half-hourly settlement.

It's higher effort than Flux or Go but can save more for people who actively manage their consumption.

How to Switch to a Time-of-Use Tariff

Confirm you have a SMETS2 smart meter (check here)
Ensure half-hourly settlement is active — ask your supplier
Research available ToU tariffs from your supplier and competitors
Switch via your supplier's app or website — takes 1–2 weeks
Set up timers on heavy appliances to run during off-peak windows

Is It Worth It for Plug-in Solar?

For a plug-in solar system without a battery, the benefit is modest. You save on avoided import during the day (which you'd save on any tariff), plus potentially cheaper overnight rates for baseline loads. Typical additional saving over a flat tariff: £30–80/year.

For a plug-in solar system with a battery, the benefit is significantly larger. You charge the battery overnight at cheap rates and from solar during the day, then discharge during expensive peak hours. Additional saving: £80–200/year depending on battery size and tariff.

Use our savings calculator to model the difference for your specific setup and location.