# Peak shaving Source: https://ordergroup.co/glossary/peak-shaving/ Last updated: 2026-10-10 > Peak shaving cuts the highest grid draw of a site with a battery or load control. How it works, tariff rules and what the EMS software must do. [Energy](https://ordergroup.co/glossary/energy/) 3 min read # Peak shaving Also known as: load peak shaving, demand peak shaving Definition Peak shaving lowers the highest power a site draws from the grid, usually by discharging a battery or cutting flexible load during the intervals the network tariff measures, so the site avoids capacity overrun fees or qualifies for a lower network charge. Cite this entry Text "Peak shaving". Order Group, Software glossary, 10 October 2026. https://ordergroup.co/glossary/peak-shaving/ HTML `Peak shaving - Order Group` Reviewed by [Michał Dżaman](https://ordergroup.co/authors/michal-dzaman/), Co-founder & Head of Backend Last reviewed 10 October 2026 ## How peak shaving works A commercial or industrial grid connection is billed for energy and for power. The power part depends on the highest load the meter records in a billing interval. Peak shaving keeps that recorded peak down. A battery discharges, or flexible load such as heat pumps, compressors or EV chargers is reduced, during the intervals when consumption would cross a threshold. The battery recharges when demand is low. The threshold and the interval length come from the network tariff, so the tariff rules decide what the control software has to do. Two models are common in Europe. In the first, the site has a contracted capacity and pays a fee whenever it goes above it. In Poland, under § 53 of the tariff regulation of September 3, 2026, the network operator works out each hour's overrun from power averaged over 15-minute periods and charges the fixed component of the network rate multiplied by the sum of the ten largest overruns in the month. Where the meter cannot record 15-minute or hourly values, the fee is ten times the largest overrun in the billing period. In the second model, the site has to keep its load low only inside time windows. In Germany, § 19(2) of the StromNEV gives a consumer whose peak predictably falls outside the annual network peak an individual network charge, which may not be lower than 20% of the published charge. Network operators publish high-load time windows (Hochlastzeitfenster, HLZF) per voltage level and season, following the Bundesnetzagentur decision BK4-13-739 of December 11, 2013. The windows apply on working days only. For 2026 one operator, N-ERGIE Netz, sets these conditions: the maximum load inside the windows must be at least 20% below the annual peak at medium voltage (10% at high voltage, 30% at low voltage), the difference must be at least 100 kW, and the yearly saving must reach at least 500 EUR. ## What peak shaving means for your software The tariff rules turn into these requirements for the specification: - The controller works on the same averaging interval as the bill. If the tariff uses 15-minute averages, the EMS tracks the running average of the current quarter-hour and how much energy is left before it crosses the limit. Reacting only to instantaneous power wastes battery capacity on harmless spikes. - The battery has to be full when the window opens. That needs a load forecast and a reserved state of charge, so the EMS charges ahead of the window and does not sell that energy. - Windows, seasons, public holidays and contracted capacity are configuration, because operators update them every year. A code release for a new tariff year is a design fault. - Peak shaving and trading compete for the same kilowatt-hours. The priority between them, and what happens when the reserve runs out mid-window, must be written down. - Battery ramp rates and conversion losses between battery and grid change how much power actually reaches the meter, so the controller needs both. - The EMS keeps its own 15-minute record of grid power and compares it with the operator's metering data. Without that record you cannot check an overrun invoice. - A missed window is expensive, so alerts must fire before the window: battery unavailable, state of charge too low, communication lost. Writing the specification? Add Peak shaving to your requirements checklist Collect the terms your project touches and get their system requirements in one e-mail, ready for an RFP. Peak shaving targets and what they require TargetRuleEMS requirementEffect of a miss Contracted capacity (Poland)Stay below the contracted power, measured as 15-minute averages per hour15-minute running average at the grid meter, fast dischargeOverrun fee: fixed network rate times the sum of the 10 largest overrunsHigh-load windows (Germany, HLZF)Keep the maximum load in the windows well below the annual peakWindow calendar, load forecast, charging before the windowLoss of the individual network charge for the yearConnection limitStay below the physical capacity of the connectionFast load limiter at the siteProtection trips or grid operator action ## From our projects Peak shaving is one of the operating modes of the EMS we built for [Skyfri](https://ordergroup.co/case-studies/skyfri-solar-asset-management-platform/), which has run fully offline on 7 plants since June 2024. As the project documentation recorded in October 2024, the first requirements for the system came from industrial sites in Germany and included peak shaving against HLZF windows, trading through an external partner and export curtailment on grid operator request. By then the main control loop and a maximum site load limiter were done. Work then in progress included live HLZF tests in November 2024, peak shaving window management, battery ramp rate management and a calculation of losses between battery and grid. An algorithm that prepares the battery before each high-load window, and further variants for other factory layouts, were next on the plan. From our projects [Skyfri - Solar & Battery Asset Management Platform How Order Group built the fully offline EMS behind Skyfri's solar platform, which controlled more than 5 MWh of battery storage across 7 live plants.](https://ordergroup.co/case-studies/skyfri-solar-asset-management-platform/) Where to get it - [Skyfri](https://skyfri.com/product) Skyfri offers an energy management platform for solar and battery sites, including peak shaving. We built its EMS. ## Related terms - [BESS](https://ordergroup.co/glossary/bess/) Battery energy storage system A battery energy storage system (BESS) stores electricity in rechargeable batteries and releases it to a site or the grid on command. It combines battery racks, a battery management system, power conversion equipment and control software. - [Demand response](https://ordergroup.co/glossary/demand-response/) Demand response is a change in electricity consumption by end users, away from their normal pattern, in reaction to prices or to a paid call from a grid operator or aggregator. It can be offered by one site or by many sites pooled through aggregation. - [EMS](https://ordergroup.co/glossary/ems/) Energy management system An energy management system (EMS) is software that reads the meters, inverters and batteries on a site and sends them setpoints, deciding when to charge, discharge, curtail or trade within grid, contract and safety limits. ## Read more on the blog - Article [Battery Energy Storage System (BESS): How It Works and What Software It Needs](https://ordergroup.co/blog/battery-energy-storage-system/) - Article [What Does BMS Mean? Battery & Building Management Systems Explained](https://ordergroup.co/blog/what-is-bms/) - Article [Energy Distribution & Production. Virtual Power Plants](https://ordergroup.co/blog/virtual-power-plant-software/) ## Sources 1. [Rozporządzenie Ministra Energii z dnia 3 września 2026 r. w sprawie sposobu kształtowania i kalkulacji taryf oraz sposobu rozliczeń w obrocie energią elektryczną (Dz.U. 2026 poz. 1182), § 53](https://isap.sejm.gov.pl/isap.nsf/DocDetails.xsp?id=WDU20260001182) - ISAP / Sejm RP 2. [Stromnetzentgeltverordnung (StromNEV), § 19](https://www.gesetze-im-internet.de/stromnev/__19.html) - Bundesministerium der Justiz 3. [Hochlastzeitfenster für atypische Netznutzung nach § 19 Abs. 2 Satz 1 StromNEV - 2026](https://www.n-ergie-netz.de/public/remotemedien/media/nng/infothek_3/veroeffentlichungen_1/weitere_veroeffentlichungen/N_Hochlastzeitfenster_2026_NNG.pdf) - N-ERGIE Netz GmbH Michał Dżaman reviewed this entry. Ask how it applies to your project. [Ask an engineer](https://ordergroup.co/contact-us/) ## FAQ ![Michał Dżaman](https://ordergroup.co/media/images/T02DHCC1Z-USU629221-c8b7d6d66b56-512.format-webp.webp) Michał Dżaman Co-founder & Head of Backend [Talk to an engineer](https://ordergroup.co/contact-us/) ### How large a battery do I need for peak shaving? It depends on how deep and how long your peaks are. Take a year of 15-minute load data from the grid meter, set the target limit, and add up the energy above it in each peak: the largest of those sums, plus losses and a state of charge reserve, sizes the battery. Power rating follows from the highest single overrun. ### What data do I need before starting a peak shaving project? At least 12 months of 15-minute interval data from the grid meter, the current tariff with its contracted capacity or windows, and the connection limit. Without interval data the sizing and the business case are guesswork. ### Can the same battery do peak shaving and energy trading? Yes, if the EMS reserves enough state of charge for the next peak window and sells only the rest. Skyfri's EMS runs both on the same sites. ### What happens if the EMS misses a single interval? Under the Polish rules one overrun enters the monthly sum of the ten largest overruns, so a single missed quarter-hour already costs money. Under the German HLZF rules one peak inside a window can cost the individual network charge for the whole year. Building a system that depends on Peak shaving? See how we build software for this domain, with case studies and the stack we use. [See Energy Hub](https://ordergroup.co/energy-hub/) Requirements checklist For each term we send the definition and what it requires from your software. Free, no sales call needed. Your checklist is empty. Use the plus next to a term to add it.