More workplace plugs or faster chargers: which serves more employees?

A free connector can matter more than headline speed

Workplace charging discussions can compare the speed printed on a station with the frustration of finding no available connector. Employees parked for a full shift have a different problem from drivers making a short highway stop. Buying the highest-power unit for every space can concentrate available capacity into too few usable stalls. Conversely, installing many very slow connections can disappoint drivers whose commute cannot be replenished during the workday.

Source: If anyone charges their EV while they are at work, how does it work out? · What’s your workplace shared-charging policy?

Calculate energy within each parking window

The relevant quantities are energy requested, parking duration, and simultaneous site power. DOE recommends evaluating employee demand before equipment selection. Vehicle acceptance limits also matter: some plug-in hybrids cannot use a high AC charging rate, while other vehicles can. A shared power system needs to allocate a defined site budget safely. It does not create additional energy, and its maximum port count says little about whether the employees' departure requirements will be met.

Source: Alternative Fuels Data Center: Workplace Charging for Electric Vehicles

Illustrative scenario: twelve employees share 24 kW

Illustrative scenario: twelve employees request 10 kWh each over eight hours. Their combined battery-energy request is 120 kWh, or 15 kW average before losses. An allocation of 24 kW may offer useful margin if vehicles stay connected and the system distributes power effectively. Four much faster ports could deliver the same daily energy but require car movement. Twelve ports at reduced power could avoid that movement, while a worker leaving after two hours may still need priority or a separate arrangement.

Survey the actual users and attendance

Survey energy needs without asking employees for unnecessary personal travel details. A useful form asks typical daily energy or commute distance, time parked, vehicle model, home-charging access, and expected days on site. Treat future EV interest separately from current demand. Include short shifts, visitors, and fleet vehicles only if they belong in the program. Otherwise the design model may count demand that never overlaps or overlook a small group with genuinely tight deadlines.

Compare three layouts at the same site limit

Compare three layouts using the same electrical budget: few high-power ports with rotation, more managed ports with all-day connection, and a mixed arrangement for short and long stays. Include trenching, accessible circulation, cable reach, network fees per port, and administration. A lower-power design can reduce some electrical requirements without reducing civil costs. Ask what happens when every port is occupied and whether vehicles receive a minimum useful allocation or are deliberately sequenced.

Check the shortest stay as well as the average workday

Divide prospective users into parking windows before comparing layouts. Someone parked for nine hours, someone on a four-hour shift, and a visitor staying ninety minutes are three different charging cases even if they request the same energy. In a simplified example, 12 kWh over eight hours requires 1.5 kW average into the battery; the same amount over two hours requires 6 kW before losses. A long average parking duration can therefore conceal a small but consequential group whose needs cannot be met by the proposed allocation.

Ask a provider to show the busiest credible overlap, not just a daily energy total. Include the point when short-stay drivers arrive while long-stay drivers are still connected. Explain how the system chooses priorities, which minimum or maximum limits apply, and what happens when the requested energy cannot be delivered. A managed system can deliberately defer a long-stay session to serve an earlier departure, but only within its supported controls and the approved site limit. A promise of intelligent sharing needs an understandable example tied to the actual vehicles and schedule.

Compare future expansion in physical and operating terms. Additional ports may need new trenching, accessible routes, communications coverage, and ongoing per-port fees even when no extra site power is allocated. Conversely, reserving useful pathways during initial construction may reduce later disruption without requiring every charger to be purchased immediately. Have the proposal state which parts of expansion are enabled, which remain unapproved, and which assumptions require review. The employer can then choose whether to invest first in more places to connect or in greater delivery capacity. Revisit the choice when attendance patterns or vehicle mix change, since a design that serves today's long-stay commuters may not serve tomorrow's short shifts equally well.

Commission simultaneous sessions

Commission the chosen layout with representative vehicles and simultaneous sessions. Record aggregate draw and delivered energy, not only successful app enrollment. Preserve the assumptions so adding ports later triggers another demand review. If remote work patterns change from two office days to five, utilization can increase sharply without a change in employee headcount. The expansion threshold should therefore be expressed as unmet charging demand and occupied connection hours, rather than an arbitrary anniversary.

Put it into practice

A decision table to keep handy