Depot flexibility calculator
Estimate your annual benefit from TOGL
Tip: Hover over the icons for detailed explanations of each field. Download the full assumptions document above for complete methodology and data sources.
Your inputs
Prices include VAT: 20% on depot, workplace and public charging, which are business supplies, and 5% on a driver’s own domestic supply. Public and workplace rates use UK averages (Zapmap Q3 2025).
Revenue share and control depend on charger-to-vehicle integration. Where TOGL has an integration with the charger or network, DR can operate on public networks too.
Tip: depot vehicles are usually plugged in whenever they are on site, so 24/7 is the common case. Vehicles taken home overnight are typically plugged in 17:00–08:00.
Projected annual benefits (2026–2030)
Showing growth in savings and revenue as grid services expand
TOU optimisation (stable)
+50% growth by 2030
+100% growth by 2030
Estimated annual benefit
£0
Charging cost reduction
£0
(0.0%)
Flex/V2G revenue
£0
Defaults reflect published NESO and distribution network data, each dated in the assumptions document.
Figures are estimates based on your inputs and editable defaults, shown against unmanaged charging on the selected tariff. Actual outcomes vary with usage, tariffs, season and participation. This model covers charging cost savings and, where enabled, flexibility revenue; capacity and network charge reduction is assessed per site against the agreed supply capacity and is not estimated here. Figures include VAT at the applicable rate, which a VAT-registered business can normally recover on the 20% standard-rated cases.
How this works
- TOGL shifts your charging to cheaper hours based on your tariff.
- Where TOGL has an integration with your vehicle, charger or network, those assets can join grid events to earn revenue.
- Select where and when you usually plug in to refine accuracy.
- Charging cost with no flexibility£0
- Charging shifted to off-peak£0
- Demand response revenue£0
- Vehicle-to-grid revenue£0
- Net annual benefit per vehicle£0
The three middle bars each come off the flat-tariff charging cost, and together they are the net annual benefit. Figures follow your inputs above, rounded to the pound, and are estimates rather than a forecast.
Savings and revenues vary by tariff, location, and plug-in availability. Figures assume average UK grid-event prices and are based on published 2025/26 tariff data.
Assumptions
Results are calculated from representative defaults drawn from published UK data: Ofgem and DESNZ tariff statistics, NESO Demand Flexibility Service results and Zapmap charging prices, each dated in the assumptions document.
Take these numbers further
These are modelled estimates. We can run the same model against your real depot: your tariff, your vehicles and the hours they are actually plugged in.
FAQ
About this calculator
How does the TOGL calculator work out savings?
The TOGL calculator combines the figures entered about a fleet with representative defaults for battery capacity, charging power, energy consumption, tariff rates and flexibility market participation, drawn from published UK and EU data. The full methodology, including every default and its source, can be downloaded from the calculator page.
Are the calculator results a quote?
No. The TOGL calculator produces indicative modelling for planning purposes, not a commercial offer. Actual value depends on duty cycle, battery size, tariff structure, site constraints, charging windows, integration availability and flexibility market access.
Why does the calculator model vehicle-to-grid when TOGL does not offer it?
Vehicle-to-grid export is modelled in the TOGL calculator for planning purposes only, so a fleet can see how the case changes if V2G becomes available over the life of its vehicles. TOGL does not offer V2G today, and the calculator separates it from the value available through smart charging now.