A time-of-use (ToU) tariff is an electricity pricing structure in which the per-kWh rate varies by time period. In its common static form, the tariff uses predefined peak, off-peak, and shoulder blocks published in advance by a utility or energy retailer. In EV charging, ToU can affect two separate layers: the electricity rate an operator pays and the customer-facing price the operator configures for drivers. Static ToU differs from wholesale-indexed dynamic pricing, where prices change according to market results and may be known only shortly before consumption, often one day ahead.
How time-of-use pricing is structured
A time-of-use tariff divides the day into priced blocks. A peak block covers the hours of highest grid demand and carries the highest rate. Off-peak blocks are generally the cheapest and are often overnight, although their timing varies by market and may include daytime periods with abundant renewable generation. The schedule is published ahead of time, often for a season or a year, so the price at any hour is known in advance. This is the main distinction between static ToU and wholesale-indexed dynamic pricing: a static ToU schedule is fixed and predictable, while a dynamic price changes according to a market or other variable index and may be published day ahead, intraday, or closer to real time.
For EV charging the distinction matters because charging is a large and movable load. A single site can add hundreds of kilowatts, and where that energy lands on the tariff clock decides much of its cost.
This is why ToU is inseparable from smart charging and demand response: the tariff sets the price signal, and EV charging software acts on it by moving sessions into cheaper blocks. The International Energy Agency names time-of-use tariffs and smart charging as two lead strategies for managing EV load on the grid. Its pilot-city target has 60% of EV charging occurring off-peak by 2025.
ToU is therefore often paired with smart charging and can complement demand response programs: the tariff sets the price signal, and EV charging software acts on it by moving sessions into cheaper blocks. Smart charging and demand response are related but separate mechanisms; a ToU tariff can also influence drivers who schedule their charging manually.
Why time-of-use tariffs matter
For a charge point operator, a time-of-use tariff is both a cost to manage and a pricing lever to pull.
On the cost side, the electricity a site buys is often its largest variable expense, and peak-rate energy can erode the margin on sessions delivered during those hours.
On the revenue side, the operator sets its own driver pricing, and it can mirror the ToU structure: charging less off-peak to attract price-sensitive drivers, and protecting margin at peak.
Two other costs shape the picture. Commercial and fast-charging sites frequently pay demand charges, billed on peak power draw rather than energy consumed, which can reach thousands per month at a low-utilization DC site, regardless of how much energy is sold. And because the charging load is schedulable, an operator that shifts it into off-peak blocks turns a cost exposure into a pricing strategy. A fleet depot is the clearest case: charging overnight, it can move a whole yard of vehicles into the cheapest hours while still meeting morning departure times. Doing that reliably across a network is a software function.
Key concepts
Peak, off-peak, and shoulder periods
These are the time blocks a ToU schedule is built from. Peak periods normally carry the highest rates during the busiest grid hours, off-peak the lowest (typically overnight), and shoulder periods bridge the two.
Dynamic pricing
Market-responsive alternatives to static time blocks. Prices may be published day ahead, intraday, or close to real time.
Wholesale day-ahead markets
Auctions that establish electricity prices for the following day, such as Nord Pool in the Nordic region and EPEX SPOT in parts of Central and Western Europe. Tariffs linked to these prices are dynamic but are not literally priced in real time.
Tariff scheduling and load shifting
Defining time-based rate rules in a management platform, then moving consumption from expensive to cheap windows in response to them.
Smart charging and demand response
Related but distinct mechanisms that can operationalize load shifting. Smart charging manages individual or aggregated charging sessions according to price, time, energy and site constraints. Demand response changes consumption in response to an external grid, market, or program signal.
Demand charges
A separate billing axis: a charge on peak kilowatt draw rather than kilowatt-hours by time, which commercial charging sites often face alongside a ToU energy rate.
How time-of-use tariffs work in an EV charging platform
In a charging platform the concept splits into two configurable objects, and AMPECO models it this way. The first is the electricity rate: the operator’s cost of energy. The second is the customer-facing tariff: the price the operator charges the driver. Keeping them separate allows the operator to compare session revenue with its underlying electricity cost without assuming that driver pricing is always a direct markup on the supply rate.
An operator can define the electricity rate as a fixed schedule, setting day and night periods and per-weekday rates in a chosen timezone, or connect a live day-ahead feed. AMPECO integrates two such feeds: Nord Pool day-ahead market prices across the Nordics, and Octopus Energy rates in the UK, covering both the Agile dynamic product and the Octopus Go off-peak window. These refresh from the market on a schedule rather than in real time. A fixed schedule represents static ToU, while a day-ahead market feed represents wholesale-indexed dynamic pricing. Both can be represented as electricity-rate inputs used for cost tracking, pricing logic and charging optimisation, while remaining conceptually distinct.
Smart charging can then act on the price curve. It shifts a session into the cheapest periods before the driver’s departure, and holds charging while the price sits above a threshold the operator sets. Throughout, it stays under the site’s circuit limit enforced by dynamic load management. In the driver app this surfaces as a price-over-time chart, the day and night rates, and an estimated saving when a session runs in optimized mode.
Time-of-use vs. related pricing
Time-of-use is easy to confuse with the pricing mechanisms next to it. The clearest way to separate them is by what sets the price.
| Time-of-use tariff | Dynamic (real-time) pricing | Demand charge | |
|---|---|---|---|
| What sets the price | A pre-defined schedule of time blocks | The wholesale market, updated daily | The site’s peak power draw |
| Known in advance? | Yes, published ahead | Only about a day ahead | The charging structure is known, but the billed amount depends on the site’s measured peak |
| Billed on | kWh consumed by time of day | kWh consumed at the applicable indexed price | Peak kW recorded during the billing period |
The subtler confusion is the word “tariff” itself. In the electricity-supply sense, a ToU tariff may describe what an operator pays its utility, retailer or energy supplier. In everyday charging-network language, an operator’s “tariff” is often the price plan it offers drivers. These are related but separate objects: the operator’s electricity rate may be an input to its customer pricing, but the driver-facing tariff does not have to mirror it. A driver-facing tariff can also use time-of-day pricing even when the operator’s own electricity-supply rate is not ToU.
Related terms
What is a time-of-use tariff for EV charging?
A time-of-use tariff is an electricity price that changes by time of day, split into peak, off-peak, and shoulder blocks set in advance. In EV charging it works on two sides: the rate an operator pays for grid power, and the time-varying price the operator can charge drivers. Charging is usually cheapest in off-peak blocks, typically overnight.
What is the difference between time-of-use and dynamic pricing?
A time-of-use tariff follows a fixed schedule of price blocks published in advance, so the peak and off-peak hours are known ahead of time. Dynamic, or real-time, pricing instead tracks the wholesale electricity market and is republished each day, so the actual price is only known about a day ahead. ToU is predictable; dynamic pricing varies.
How do EV drivers save with time-of-use tariffs?
Drivers save by charging during off-peak blocks, when the per-kWh rate is lowest. Because an EV is often parked far longer than it needs to charge, a charging app or home charger can delay a session until the cheap window opens and still finish before departure. Overnight home charging is the most common way drivers benefit.
Can EV charging be scheduled to off-peak times automatically?
Yes. This is a core function of smart charging: a charge point management system reads the tariff schedule and automatically shifts a session into the cheapest periods, pausing or throttling as needed, while still meeting the driver’s departure time and the site’s power limit. The driver plugs in as normal and the software handles the timing.
Do time-of-use tariffs and demand charges apply together at EV charging sites?
They can. A time-of-use tariff sets the price per kWh by time of day. A demand charge is separate: it bills the site’s highest power draw in a period, measured in kilowatts, regardless of energy used. Commercial and fast-charging sites often face both at once, so controlling peak draw matters alongside shifting energy to off-peak hours.
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