Quick answer
Reducing the highest electrical demand at a defined boundary through load management, on-site supply or storage, subject to measurement, equipment and tariff constraints.
What Is Peak Shaving?
Answer: Peak shaving reduces the highest demand at a defined electrical boundary by managing loads, supplying on-site power or dispatching storage. For a facility, it often targets grid-import peaks that affect demand charges. The achievable reduction depends on the tariff’s measurement interval and windows, load pattern, controls and available equipment power and energy; savings are not guaranteed.
The distinction from peak load is practical: peak load identifies the maximum; peak shaving is an intervention to reduce it. A site can reduce utility import while its underlying production or building load stays the same.
Peak Shaving, Load Shifting and Arbitrage
| Strategy | Main objective |
|---|---|
| Peak shaving | Lower the relevant maximum demand |
| Load shifting | Move consumption to another time; it may also shave a peak |
| Energy arbitrage | Use differences in energy prices, after losses and other costs |
| Demand response | Meet a program’s requested reduction or dispatch conditions |
These strategies can overlap, but they are not interchangeable. Moving charging to a cheaper energy-price period can still create a new demand peak. A grid-service payment also follows program terms rather than automatically reducing the site’s demand bill.
The DOE utility-rate guide identifies time-window, non-coincident, look-back and system-peak demand components. Read the actual tariff before choosing a control target.
A Practical Evaluation Sequence
- Establish the bill and measurement basis. Retain the current tariff, demand units, interval, windows and billing rules.
- Review aligned interval data. Reconcile meter data with bills, identify repeated and exceptional peaks, and overlay coincident PV output.
- Evaluate operational changes. Stagger supported equipment starts or adjust flexible processes without assuming every load can be moved safely or without cost.
- Choose a candidate import target. Test all relevant intervals, including seasons and repeated events.
- Check storage power and energy. Apply supported continuous/transient limits, SOC availability, temperature and conversion boundaries.
- Model recharge and verify controls. Test whether the battery can recover before the next event without creating another billable peak.
Use data at a resolution suitable for the utility’s actual demand interval. Fifteen-minute data is not a universal requirement, and monthly bills remain useful for tariff and total-charge reconciliation even when insufficient for dispatch sizing.
Battery Power and Event Energy
Consider a hypothetical site with a 200 kW net load before storage for 30 minutes, and a desired 150 kW import target. At the AC import/load boundary, required discharge is:
Power = 200 − 150 = 50 kW.
Delivered event energy = 50 × 0.5 = 25 kWh AC.
If an assumed discharge path is 90% efficient, that requires 25 ÷ 0.90 = 27.78 kWh available at the declared battery DC boundary. This is not a selected battery’s nominal capacity: usable-window, reserve, degradation and power-limit checks remain necessary.
For irregular events, sum the required support over the actual time series rather than multiplying peak depth by an average duration and a universal 1.2 factor. Several peaks before recharging can need more energy. A long plateau and a short spike with the same maximum kW have different requirements.
The SAM dispatch documentation describes peak-shaving attempts subject to capacity and SOC constraints. That is a useful modeling boundary, not proof any real controller will perfectly maintain a target or has a perfect forecast.
Control Is Different from Battery Protection
A site energy-management or dispatch controller uses meter information and targets to request charging or discharge. The battery management system enforces supported battery conditions. The BMS alone is not automatically the site-demand controller.
Verify measurement coverage, supported communication, control response and the behavior at empty storage, lost communication or equipment limits. Commission the complete supported system against the relevant averaging interval and operating conditions. Do not promise instant response or a perfect demand cap simply because a battery is installed.
Charging creates load. For example, assumed 130 kW site demand plus 30 kW grid charging creates 160 kW import. That would exceed a 150 kW target if the same demand rule applies. A low energy price does not make this recharge interval harmless to demand charges.
Savings Example and Limitations
Under a hypothetical simple monthly tariff with no ratchet, floor or other demand component, lowering billing demand from 200 to 150 kW at $12/kW reduces that component by $600 for that month.
This is not automatically $7,200 annual savings: each month’s load, tariff and achieved billing demand must be assessed. A missed interval, recharge peak or look-back floor can change the result. Include charging cost or foregone export value, round-trip losses, degradation, controls, maintenance and replacement when assessing economics. No universal 4–7-year payback or 80/20 savings rule follows from the strategy.
Designers should document the target, event coverage, forecast assumptions and failure scenarios. Installers and facility teams should validate the released monitoring/control arrangement and operating handoff. Sales teams should distinguish modeled demand reduction from contractual performance. When evaluating SurgePV, ask which interval dispatch, storage constraints and tariff calculations the workflow supports.
Common Questions
Do you need batteries for peak shaving?
No. Load management or coincident on-site generation can reduce a peak. Batteries add controllable supply within their available power, energy and supported configuration.
How much can peak shaving save?
Calculate it from the current tariff and the changed billing-demand series. A reduction in one event’s import is not sufficient evidence of monthly or annual bill savings.
Is load shifting the same as peak shaving?
No. Shifting moves consumption in time; it may shave the original peak or create a new one. Evaluate the complete demand and energy-charge effects.
Related Glossary Terms
About the Contributors
CEO & Co-Founder · SurgePV
Keyur Rakholiya is identified by SurgePV as its CEO and a company co-founder. His SurgePV author page lists only role information that can be tied to the public profile below; credentials, project totals, testing claims, media appearances, and speaking engagements are not asserted without retained evidence.
Editorial contributor · SurgePV
Rainer Neumann is credited as an editorial contributor on SurgePV content. This profile does not assert engineering credentials, project totals, software-testing experience, education, speaking engagements, or media citations because independent verification evidence is not retained in the publication record.
