From Duty Cycle to Grid Connection: Building a Defensible Load Profile

A fleet plan shows when vehicles operate and how much energy they need to recharge. It does not yet determine when or at what power the site draws electricity. Chargers, connection limits, priorities, faults, and the actual assignment of vehicles turn mobility demand into an electrical load profile.

Four layers that should remain distinct

Layer	Core inputs	Planning output
Vehicle operation	Duty cycles, consumption, arrival, departure, state of charge	Energy need and time window per vehicle
Charging infrastructure	Quantity, power, connector type, availability	Technically possible charging sessions
Operational control	Priorities, assignment, queue, power limit	Delivered charging sessions and electrical load profile
Energy system	Grid, tariff, PV, storage, control strategy	Grid import, energy cost, and investment alternatives

Why daily energy does not determine connection capacity

Two sites can deliver the same daily energy and still create very different power peaks. If demand is spread across long dwell periods, a limited connection may be sufficient. If many vehicles arrive together with short departure windows, simultaneity, waiting time, and peak power increase. A blanket coincidence factor hides this dynamic.

The National Centre for Charging Infrastructure’s May 2026 guide therefore recommends a systematic assessment of vehicle count, mileage, energy demand, dwell time, availability, and operating priorities. It also identifies the existing site load profile as the basis for determining whether spare connection capacity can be used.

Metrics an operations simulation should provide

Energy service level: the share of vehicles that reach their required departure energy on time.

Waiting and queues: not only averages, but critical time windows and outliers.

Power: peak value, peak duration, and the profile at the grid connection, transformer, and chargers.

Utilisation: occupancy and power use by charger, technology, and buildout phase.

Robustness: the impact of late arrivals, higher consumption, charger faults, or constrained grid power.

A defensible planning sequence

Clean operating data and document assumptions for consumption, state of charge, and electrification.
Convert individual vehicle needs into time-resolved charging sessions.
Simulate infrastructure alternatives and control rules against the same demand.
Advance only the variants that meet defined service targets under stress cases.
Use the resulting electrical load profile for grid, PV, storage, and economic analysis.

Why this separation matters to planners and operators

When each modelling layer retains its own inputs and outputs, changes can be recalculated selectively. A revised duty cycle, an additional MCS point, or a new grid limit no longer requires the entire plan to be rebuilt. conduix provides one consistent scenario model linking assumptions, operating results, and energy-system alternatives.