Dynamic electricity tariffs with solar — is it worth it?
On a dynamic tariff you pay the hourly wholesale price plus network charges and the supplier’s margin — Tibber and Octopus in Europe, Amber in Australia, and a growing list elsewhere. Prices swing severalfold within a day: sunny middays are dirt cheap or negative, winter evenings expensive. For the average consumer it’s a lottery; for a solar owner with flexible loads or a battery, it’s a tool. I write this as someone who has lived on a dynamic tariff for years.
How it works in practice
Billing follows day-ahead market prices — and those are published the afternoon before. That’s the underrated core of the model: every evening you can plan the entire next day. Cheap hours are typically overnight and sunny middays; expensive ones are the morning and evening ramps (7–9 am, 6–9 pm).
Who comes out ahead
It pays if at least one is true: you have solar (your own production covers the middays anyway), you can shift big loads (water heating, laundry, EV), you have a battery (arbitrage: charge cheap, discharge dear), or you heat with a buffered heat pump.
It doesn’t pay if: your consumption sits immovably in the price peaks, you value a predictable bill above optimisation, or even a minute of daily planning annoys you.
A real day on a dynamic tariff
Sunny day: overnight, whatever must be ready by morning charges in the cheap trough; through the day the house lives off its own production, with hot water, dishwasher and EV in the production peak; during the expensive evening ramp almost nothing runs, because everything important already did. Overcast day: the plan inverts — the big loads move into the cheapest tariff hours.
The decisive input is two forecasts combined: tomorrow’s prices (known) and tomorrow’s production (forecast). Only together do they answer whether the water heats on sunshine at 1 pm or on cheap grid power at 3 am. Automating exactly that loop is what home energy-management systems (EMS) are for — I currently run it semi-automatically in Home Assistant with Volcast forecast sensors (the HA integration requires Premium). Australia’s Amber ecosystem, where households pay a subscription for automated wholesale optimisation, shows where this is heading everywhere.
The risks, stated plainly
Prices can also spike: a cold, windless evening means several times the average rate. Without flexibility, a dynamic tariff can end up more expensive than a flat one. Rule of thumb: switch only once you can shift at least 30–40% of your consumption — or a battery smooths the peaks for you.
FAQ
Can I still export on a dynamic tariff? Yes — export is settled independently (fixed feed-in or wholesale-linked, depending on market and provider); the dynamic side mainly changes what you pay for imports.
Where do I see tomorrow’s prices? In your provider’s app or public day-ahead dashboards — published each afternoon for the next day.
What happens during negative prices? Importing is effectively rewarded — the ideal hour for battery charging and big loads. More in the negative prices article →.