New issue Im seeing in Phoenix ? commercial properties installing EV charging stations without understanding the demand impact. Hotel client with APS account installed 12 Level 2 chargers in their parking structure. Each charger draws 7.2 kW. If all 12 are in use simultaneously thats 86.4 kW on top of existing building demand. Their monthly demand spiked from 380 kW to 465 kW. Demand charges went up $1,020 per month. The hotel thought EV charging would be a free amenity powered by their existing electrical service.
Electric vehicle charging stations spiking commercial demand
Karen ? EV charging demand impact is the hot topic in Scottsdale right now. APS has a specific EV charging tariff pilot E-63 that meters charging separately from building load. The demand charge for EV charging under E-63 is lower than standard commercial demand rates. If the hotel separates the EV charging onto its own meter under E-63 the total demand charges could be lower than combined on one meter.
Gina ? separate metering is an option but APS charges $2,500 for a new commercial meter installation plus monthly customer charges for the second account. Need to model whether the demand charge savings from separation exceed the cost of a second meter.
This is going to be an enormous audit opportunity over the next 5 years as commercial EV charging expands. Every commercial property adding EV chargers needs to understand the demand charge impact. The ones that dont plan for it will see demand charge increases of 15-25% from EV load alone. Auditors who understand EV charging tariff options will have a significant competitive advantage.
Marcus is right about the opportunity. Im now asking every commercial client whether they have or plan to install EV charging. Three more clients in Phoenix are in the process. Im positioning the demand charge analysis as part of the EV installation planning rather than a post-installation audit. Proactive consulting pays better than retroactive error-finding.
In Boise, Idaho Power is seeing the same issue. They introduced a special commercial EV rate that bills EV charging demand separately and uses a lower demand charge. But they also offer a managed charging option where the utility can throttle charging during peak demand periods in exchange for even lower rates. The managed charging approach prevents EV stations from contributing to building peak demand entirely.
EV charging demand is the fastest-growing demand charge issue in commercial utility auditing. Key recommendations for clients: 1) Always model demand impact before installing chargers 2) Investigate EV-specific tariffs and separate metering options 3) Consider managed charging programs that limit coincident peak contribution 4) For DC fast charging, battery buffered charging stations can dramatically reduce demand spikes by charging from battery rather than grid during peak periods. Vernon is correct that DC fast charging will fundamentally challenge traditional demand charge structures.
The demand impact of DC fast chargers is even more dramatic. A single DC fast charger can draw 150-350 kW. A gas station installing 4 DC fast chargers could see demand charges exceeding their gasoline profit margin. TVA territories are already seeing this issue with Buc-ees and other truck stop operators adding fast charging. The demand charge structure was never designed for these loads.