Demand Charges Explained: The Hidden Utility Cost of EV Charging for HOAs

Demand charges are a part of commercial electricity bills that many HOA boards have never had to think about, until they install EV chargers. Unlike the energy charge, which bills you for the total kilowatt-hours (kWh) you consume over a month, a demand charge bills you for the single highest spike in power your building draws at any one moment, measured in kilowatts (kW). Utilities meter that peak in 15-minute intervals and charge a rate that commonly runs from 10 dollars to 25 dollars per kW, and in some urban markets exceeds 40 dollars per kW.

The reason utilities do this is infrastructure. The grid, transformers, and wires serving your property must be sized for the most electricity you might pull at once, not your average use. A building that draws a steady 50 kW costs far less to serve than one that spikes to 200 kW for 20 minutes each evening. Demand charges recover the cost of that standby capacity.

For a small residential-style HOA on a flat or tiered rate, demand charges may not appear on the bill at all today. But adding several Level 2 chargers, each pulling 7 to 11 kW, can push a property onto a commercial rate schedule that includes them. That shift is one of the most common budget surprises boards encounter after an EV project.

When your building crosses a certain size or adds significant new load, the utility may move you from a simple residential rate to a commercial "general service" tariff. These tariffs split your bill into an energy charge (cents per kWh) and a demand charge (dollars per kW of peak). On many commercial accounts, the demand portion alone accounts for 30 to 70 percent of the total bill.

The peak that sets your demand charge is whatever the highest 15-minute average is during the billing period. If four EV drivers happen to plug in at 6 p.m. while the building's elevators, lighting, and HVAC are also running, that combined peak, not any single charger, is what you pay for every month.

Some utilities also apply a "ratchet," meaning your demand charge for the next 11 months is based partly on your highest peak of the year. One bad evening in July can inflate your bill well into the following spring.

Consider a 60-unit condo that installs eight 9.6 kW Level 2 chargers. If all eight run at once, that is roughly 77 kW of new demand on top of the building's existing 90 kW base load, for a combined peak near 167 kW. At a demand rate of 18 dollars per kW, the EV-driven portion alone adds about 1,400 dollars to the monthly bill, close to 17,000 dollars a year, before counting the energy the cars actually use.

Now compare that to a managed scenario. If software caps the eight chargers so they never collectively exceed 30 kW, the same residents still get fully charged overnight, but the added demand cost falls to roughly 540 dollars a month. The cars draw the same total energy; only the timing changes. That difference is the single biggest lever a board has over EV operating costs.

The good news is that demand charges are highly manageable with the right design, and most of these strategies cost little while paying for themselves quickly:

Many utilities now offer EV-specific commercial rate schedules designed to soften demand charges during the early years of adoption. Southern California Edison's Charge Ready and PG&E's Business EV rate, for example, phase out or replace demand charges with higher time-of-use energy rates that reward off-peak charging. Con Edison in New York offers per-plug demand-charge rebates through its PowerReady program.

Before finalizing any installation, ask your utility account representative whether an EV or time-of-use commercial tariff is available, and run the numbers on both. The right rate plan, combined with overnight charging, can cut demand-related costs by half or more.

Demand charges rarely appear in a basic installation quote, yet over a charger's 10-year life they often dwarf the hardware cost. Boards that raise these questions early avoid the most expensive EV surprises: