Six ports, six percent
The defaults describe a modest site: six ports, 3.2 sessions per port per day, 28 kWh a session. That is 576 sessions and 16,128 kWh a month, which sounds busy until you work out the plugged-in hours. At 62 kW average delivered power a session lasts 27 minutes, so the ports are occupied for 260 hours out of 4,320 available. Utilisation is 6 percent.
At 46 cents a kWh the site takes $7,418.88 and keeps $875.10. The margin is 11.8 percent of revenue and $1.52 a session, which is a real business but a thin one.
The demand charge does not care how busy you are
Of the $6,543.78 of cost, the demand charge is $3,135 — nearly half, and more than the $1,887.32 the energy itself costs. Spread over 16,128 kWh that is 19.44 cents per kWh sold, which is well above the 11 cents paid for the energy.
The important property is that it barely moves with volume. Double the sessions at the same peak and the demand charge per kWh halves to 9.72 cents, and the margin goes from $875.10 to $5,425.20 — more than six times, on twice the volume. Halve the sessions instead and the site loses money. That asymmetry is the whole reason charging sites live or die on utilisation rather than on price.
The break-even is closer than it looks
Each session contributes $7.90 after energy, processing and the host share. The costs that do not move with volume are $3,675 a month. That is 466 sessions, or 2.58 per port per day against the 3.2 assumed. The site is running at 1.2 times break-even volume.
Read the other way, the price that breaks even at the current volume is 39.9 cents against the 46 charged. Six cents of headroom on price and 0.62 sessions per port per day of headroom on volume is not much cushion, and a site modelled with an optimistic utilisation number can cross into a loss without anything visible going wrong.
What this month does not include
The capital cost is missing and it is usually the largest number in the file. On a fast charging site the equipment is frequently the smaller half of it — the transformer, the trenching, the service upgrade and the utility work make up the rest, and they vary by an order of magnitude between a site with capacity in the ground and one without. Maintenance, vandalism, idle fees, roaming arrangements and every grant or credit programme are likewise absent.
What is here is one operating month with everything visible: what came in, the four things that took it back out, and how the answer moves with the one variable that matters. Use it to test whether a site works before the capital question is worth asking, because a site whose operating month does not clear will not be rescued by the capital line.
Questions people ask
Are EV charging stations profitable?
It turns entirely on utilisation and on the demand charge, and the page computes rather than asserts. With the defaults — six ports at 6 percent utilisation, 46 cents a kWh — the site clears $875 a month on $7,419 of revenue. Halve the sessions and it loses money; double them and the margin more than quadruples, because the demand charge is close to fixed.
Why is the demand charge so large on a charging site?
Because it is billed on the highest short interval of power rather than on energy, and a charging site is exactly the load that produces a high peak against low total kWh. With the defaults it is $3,135 a month against $1,887 of actual energy — 19.44 cents per kWh sold on top of the 11 cents paid for the electricity itself.
What utilisation does a charging site need?
On these numbers, 2.58 sessions per port per day, which is 4.9 percent utilisation. That is specific to this cost structure and moves with every field on the form. The general shape holds though: the break-even is set by fixed costs divided by the contribution of one session, and the fixed costs are dominated by the demand charge.
What price per kWh should a charging site charge?
The page gives you the break-even price at your own volume rather than a recommendation — 39.9 cents with the defaults, against the 46 charged. What the market will bear is a different question and depends on what is nearby and on what drivers pay per minute of their time, neither of which is arithmetic.
Does this include the cost of building the site?
No. It models one operating month. Equipment, trenching, transformers, service work and utility charges are the largest number in most charging business cases and vary enormously with what is already in the ground. The point of an operating model is to find out whether the month clears before the capital question is worth asking.