Time-of-use tariffs give you fixed cheap windows. Dynamic tariffs go further: the price changes every half hour (or hour) with the wholesale market, and your charger buys when power is cheapest - sometimes close to free, occasionally even negative. For an EV owner with a smart charger, it is the most aggressive savings play in home energy.
How dynamic pricing works
Wholesale electricity prices swing with supply and demand: windy nights and sunny middays push prices toward zero; winter weekday evenings spike them. A dynamic tariff passes those prices to you, plus the supplier's fixed adders (network charges, levies, margin). Instead of two or three fixed rates a day, you get 48 (UK, half-hourly) or 24 (hourly, common in EU/Nordics) different prices tomorrow, published the afternoon before.
| Style | Example | Price behavior | Who offers it (2026) |
|---|---|---|---|
| Half-hourly tracker | Octopus Agile (UK) | 4-35p/kWh typical range; plunges on windy nights, spikes 4-7 PM | UK suppliers; Octopus also in parts of EU/Texas |
| Hourly spot | Tibber, aWATTar-style (EU), Griddy heritage (US) | Day-ahead hourly Nord Pool/EPEX prices + adders | Germany, Nordics, Netherlands, Spain; limited US equivalents |
| Wholesale pass-through (AU) | Amber Electric | Real-time NEM prices + fixed monthly fee; negative prices in solar hours happen | Australia (NEM states) |
Tariff structures from supplier documentation, November 2026. Availability is postcode-dependent everywhere; US dynamic retail pricing remains patchy outside Texas and pilot programs.
What an EV owner actually saves
The car is the perfect dynamic-tariff load: big, flexible, and indifferent to timing. A UK Agile household charging 3,400 kWh/year mostly in the cheapest 4-6 overnight slots pays roughly 8-12p/kWh average - 40-60% below the standard variable rate. Amber customers in Australia regularly charge at effective prices under A$0.10/kWh in solar-soaked middays. Annual savings versus a flat rate: typically $250-600 / £200-450 / A$400-700 for an average-mileage EV, more if you also shift the dishwasher and hot water.
The automation that makes it livable
Nobody babysits price curves. The ecosystem that makes dynamic tariffs practical:
- Smart chargers with tariff integration. Ohme (UK) is the reference implementation - it reads Agile prices and builds the cheapest schedule that still fills the car by your departure time. Hypervolt and Zappi have similar features.
- Car-side scheduling. Tesla and several others let the car itself follow a tariff when the charger is simple.
- Home batteries. A battery turns dynamic tariffs from "EV savings" into "whole-house arbitrage": buy at 4p, use at 35p. See home battery basics.
The honest risks
- Price spikes are real. Winter cold snaps have pushed UK Agile above 60p/kWh and Texas wholesale past $1/kWh in extreme events. If your house cannot avoid evening peak usage (electric heating, early-evening cooking), a bad month can erase a good quarter. Dynamic tariffs suit households whose non-EV usage is modest or shiftable.
- Automation dependence. When the charger app or cloud integration fails, you default to charging at whatever price is live. Set the car's own charging schedule as a fallback cap (e.g., never charge 4-7 PM).
- Mental overhead. Most owners check prices less and less as automation proves itself, but the first months involve more app-checking than a flat rate ever demands. Some people hate that; it is a legitimate reason to choose a simple off-peak tariff instead.
Dynamic vs fixed TOU: which one?
- Choose dynamic if you have a smart charger with tariff integration, an EV that covers a big share of usage, and tolerance for variable bills. Ceiling savings are highest here.
- Choose fixed TOU/EV tariff if you want set-and-forget with a guaranteed cheap window and no spike exposure. You give up maybe 20-40% of the potential savings for certainty.
What to read next
- Off-peak tariffs: the simpler alternative
- Is time-of-use worth it? The break-even math
- Why you need a smart meter first
Sources: Octopus Agile and supplier tariff documentation, Tibber/aWATTar product pages, Amber Electric terms, Nord Pool day-ahead price data. Checked November 2026.