If demand charges are the problem, peak shaving is one of the cleanest solutions. It's a term you'll hear from energy consultants, battery vendors, and load management software companies — often without a clear explanation of what it actually means or when it's worth doing.
Put simply: peak shaving is the practice of trimming the short bursts of high power draw that set your demand charge, so those brief spikes never register on your utility meter. For any commercial site adding EV charging, it's the difference between paying for the power you use and paying for the one moment you used the most.
What Is Peak Shaving?
Peak shaving reduces the highest point of a facility's electricity demand curve. Because commercial demand charges are billed on your single highest 15-minute average draw in a billing period, lowering that one peak — even briefly — directly reduces the demand charge for the entire month.
The word "shaving" is literal. Picture your facility's power draw over a day as a jagged line. Most of the time it hovers within a normal band, then occasionally spikes when several high-load devices run at once. Peak shaving cuts the tops off those spikes, flattening them back down toward the baseline before they set a new demand peak.
The core idea: You don't have to reduce total energy use to reduce a demand charge. You only have to prevent the few short moments when everything runs at once. Shave those peaks, and the meter never records the number that drives the bill.
Why the Peak Is What Matters
Utilities size their infrastructure — transformers, transmission lines, generation capacity — around each customer's maximum possible draw. The demand charge recovers that fixed cost. Because the billed peak is a single 15-minute window, a facility that draws 250kW for 15 minutes once a month pays the same demand charge as one that draws 250kW every afternoon. Peak shaving exploits that: eliminate the rare spike, and you're billed as if it never happened.
How Peak Shaving Works in Practice
There are two main ways to shave a peak, and they're often combined.
1. Active Load Management
Load management software watches total facility demand in real time and temporarily curtails flexible loads when the site approaches a peak threshold. EV chargers are the ideal flexible load — a charging session can be slowed for a few minutes without meaningfully affecting the driver, whereas you can't dim the lights in a service bay or pause a rooftop HVAC compressor mid-cycle. When the risk window passes, full power resumes.
2. Battery Storage Discharge
A battery charges during low-demand periods and discharges during peaks, supplying part of the facility's load from stored energy so the grid draw — the number the meter records — stays below the peak threshold. Batteries add cost and complexity but can shave peaks that aren't tied to a flexible load, and they pair well with solar.
Example: What one shaved peak is worth
Note that nobody charged fewer vehicles and nothing was switched off — the same energy was delivered, just reshaped so it never stacked into a single spike.
Peak Shaving vs. Load Shifting
These two terms get used interchangeably, but they solve different problems.
- Peak shaving lowers the height of a demand spike at the moment it happens. It targets the demand charge (billed per kW).
- Load shifting moves energy-consuming activity to a different time — usually off-peak hours. It mainly targets time-of-use energy charges (billed per kWh).
A fleet that charges its vehicles overnight instead of at 5pm is load shifting. A dealership that briefly slows a fast charger so it doesn't coincide with the service bay's afternoon peak is peak shaving. Most well-designed sites do both: shift what you can to cheaper hours, and shave the peaks that remain.
The best results come from combining the two. Load shifting handles the predictable, schedulable load; peak shaving handles the unpredictable coincidences that shifting alone can't catch — like a customer plugging into a fast charger at the exact wrong moment.
Why Peak Shaving Matters for EV Charging
EV chargers — especially DC fast chargers — are among the highest-instantaneous-load devices a commercial site can add, and their use is often unpredictable. A single 150kW charger can nearly double a small facility's peak in one 15-minute window. That combination of high magnitude and poor predictability is exactly what peak shaving is built to handle.
Because EV charging is flexible in a way most commercial loads aren't, it's the perfect candidate for active load management. A charging session can absorb a brief slowdown without the driver noticing, which means peaks can be shaved automatically and continuously — without staff intervention and without turning anyone away.
This Is What Energy Guardian Does
Energy Guardian is EVready's load management system for exactly this purpose. It continuously reads total building load, forecasts the 15-minute interval demand, and shapes EV charging output to keep the facility below its demand ceiling. Chargers stay available; the peak never spikes. Sites typically see a 35–55% reduction in EV-related demand charges with no reduction in charging availability. See how Energy Guardian works →
Berger Chevrolet · Grand Rapids, Michigan
Berger Chevrolet designed Energy Guardian load management in from day one rather than retrofitting after the first surprising bill. By shaving the peaks created when customer charging coincided with the dealership's existing load, the site avoided a recurring demand charge that would have applied every month regardless of charger utilization.
Is Peak Shaving Right for Your Site?
Peak shaving delivers the most value when a meaningful share of your peak demand comes from flexible or intermittent load — which is nearly always true once EV charging is involved. A few questions to gauge the opportunity:
- Is EV charging a major contributor to your peak? The larger the charger load relative to your baseline, the more there is to shave.
- Are your peaks brief and occasional? Short, infrequent spikes are the easiest and most valuable to eliminate.
- What's your demand charge rate? At $14–$22/kW, every 10kW shaved is worth $140–$220 per month.
- Can your charging tolerate brief slowdowns? Almost all commercial charging can — most sessions finish well within their window even with occasional curtailment.
The answers determine whether software-based load management is enough, whether battery storage makes sense, or whether a combination is optimal. That's the kind of analysis EVready's Playbook assessment runs before any hardware is committed.
Common Questions
What is the difference between peak shaving and load shifting?
Peak shaving reduces the height of a demand spike at the moment it happens — trimming the peak kW so it never registers. Load shifting moves energy-consuming activity to a different time of day, usually off-peak hours. Peak shaving targets the demand charge (per kW); load shifting mainly targets time-of-use energy charges (per kWh). They are complementary and often used together.
Does peak shaving require battery storage?
No. Peak shaving can be achieved with battery storage that discharges during peaks, but it can also be done with active load management that curtails flexible loads such as EV charging in real time. For most commercial EV charging sites, software-based load management delivers peak shaving at a lower cost than batteries, though the two can be combined for sites with very high demand.
How much can peak shaving save on demand charges?
Savings depend on how much of your peak is driven by flexible load and your utility's per-kW demand rate. For sites where EV charging is a major contributor to peak demand, active load management typically reduces EV-related demand charges by 35–55% without reducing charging availability.
Will peak shaving slow down my EV charging?
Well-designed peak shaving reduces charger output only during the brief windows when the facility is near its demand ceiling, and only by as much as needed. Chargers stay available throughout, and most sessions complete within their normal window because peaks are short. The trade-off is a small amount of charging flexibility in exchange for avoiding a demand charge that applies to the entire month.
Peak shaving isn't exotic — it's disciplined timing applied automatically. EVready's Playbook maps your demand exposure, models how much of your peak is shaveable, and designs Energy Guardian load management in from day one. Learn how Energy Guardian works →