Tesla Told Supercharger Hosts That Five Sessions a Day Halves Their Energy Cost. Its Own Calculator Assumes Seven.

Tesla has spent two years persuading businesses to buy Superchargers. On 1 October 2026 it published something more useful than a sales pitch: an explanation of why a half-empty one is expensive to run.

The guide, titled "How Higher Supercharger Site Utilization Increases Your Profits", is aimed at Supercharger for Business customers — the programme under which a company buys Tesla hardware, hosts it and sets its own retail price. It walks through a commercial electricity bill line by line.

The six parts of the bill

Tesla calls the fourth line "often the most expensive". A demand charge is levied on the highest power a site draws at any moment in the billing period, typically measured over a short window. Four cars arriving together for ten minutes can set a figure that is then charged for the whole month, whether the stalls are busy afterwards or empty.

Demand charge dilution

The consequence is counter-intuitive, and it is Tesla's argument. Because the demand charge is already fixed by that one peak, every additional session that fits underneath the existing peak adds energy cost but almost no demand cost. Spread the same monthly demand charge across more kilowatt-hours and the average cost per kilowatt-hour falls.

Tesla's name for this is demand charge dilution, and it puts a number on it: moving a stall from one charging session a day to five "could reduce average energy cost by more than half", assuming the monthly peak does not move. The saving is steepest at the start and then flattens, approaching a floor set by the energy charge alone — past a certain point there is no demand charge left to dilute.

The tension with Tesla's own numbers

This is where the guide sits awkwardly beside Tesla's own sales tool. When TeslAnt examined the Supercharger for Business calculator in April 2026, the modelled sites ran at roughly 300 to 450 kWh per post per day — on typical session sizes, something like seven cars per stall per day.

The new guide's illustration tops out at five. In other words, the payback periods Tesla publishes to prospective hosts already assume a site operating past the steep part of the savings curve — a site that has solved the utilisation problem this guide exists to explain. The calculator's headline figures are what a busy Supercharger earns, not what a new one earns in its first year.

That is not a contradiction so much as a missing middle, and it is the number a prospective host most needs: what the economics look like between one session a stall and seven.

Why this reads differently in Europe

Demand charges are not an American peculiarity. Commercial tariffs across Europe bill a capacity or peak-power component alongside consumption, and for a charging site the peak is set by the worst-case moment rather than the average day. Grid connection capacity is also the constraint European operators complain about most often.

That makes the guide directly relevant to Tesla's European B2B hosts rather than a US-only explainer. EVIO in Portugal has 22 Supercharger sites and 176 stalls in its pipeline under the programme, and EVgo agreed to deploy 500 kW Tesla V4 hardware under its own brand with Tesla building and operating it.

It also matches what Tesla says to drivers. Reporting its third-quarter charging numbers, charging lead Max de Zegher put the same mechanism in consumer terms: "High utilization = affordable Supercharging." The guide is that sentence with the utility bill attached — and the honest version of it is that the saving is largest for the host who is struggling, and nearly exhausted for the one who is already full.