# aFRR Source: https://ordergroup.co/glossary/afrr/ Last updated: 2026-10-10 > aFRR (automatic frequency restoration reserve) for energy software buyers: how activation works, Polish market rules and what a BESS controller needs. [Energy](https://ordergroup.co/glossary/energy/) 4 min read # aFRR Automatic frequency restoration reserve Also known as: automatic frequency restoration reserve, secondary reserve Definition aFRR (automatic frequency restoration reserve) is a frequency restoration reserve that the grid operator activates automatically, by sending setpoints from its frequency controller, to bring system frequency back to its nominal value. In Poland it must reach full activation within 5 minutes. Cite this entry Text "aFRR". Order Group, Software glossary, 10 October 2026. https://ordergroup.co/glossary/afrr/ HTML `aFRR - Order Group` Reviewed by [Paweł Zieliński](https://ordergroup.co/authors/pawel-zielinski/), Co-founder & Business Owner Last reviewed 10 October 2026 ## How aFRR works When generation and consumption drift apart, grid frequency moves away from 50 Hz. The EU system operation guideline (Regulation 2017/1485, SO GL) defines the reserves that bring it back. Frequency containment reserves (FCR) contain the deviation first. Frequency restoration reserves (FRR) then restore frequency to its nominal value. Replacement reserves (RR) restore or support the required level of FRR. FRR comes in two forms. Automatic FRR (aFRR) is, in the guideline's words, FRR that can be activated by an automatic control device. The transmission system operator's frequency restoration controller continuously computes a setpoint and sends it to the providers. The full activation time is the period between the controller setting a new setpoint and the corresponding activation or deactivation of aFRR. Manual FRR (mFRR) is activated on instruction, with a longer full activation time. aFRR is bought in two parts. Balancing capacity pays the provider for holding a band of power available, separately upwards (more generation or less consumption) and downwards. Balancing energy pays for the energy actually delivered when the reserve is activated. Since June 1, 2022 the TSOs connected to PICASSO, the European aFRR platform run under ENTSO-E, have exchanged aFRR balancing energy through it. Frequency reserves in Poland and their full activation times ReserveActivationMaximum full activation time (PSE rules)Role FCRAutomatic, local frequency measurement30 secondsStops the frequency deviationaFRRAutomatic, setpoint from TSO controller5 minutesRestores frequency to 50 HzmFRRManual instruction from TSO12.5 minutesRelieves aFRR, handles larger imbalancesRRManual instruction from TSO30 minutesRestores the FRR level ## Ancillary services and aFRR in Poland Ancillary services is the umbrella term for services a grid operator buys to keep the system stable. Frequency reserves (FCR, aFRR, mFRR and RR) are the market-based core of it; other services, such as voltage control or black start capability, are contracted differently. In Poland the second stage of the balancing market reform came into force on June 14, 2024 with PSE's new balancing rules (WDB, Warunki Dotyczące Bilansowania). Since then PSE buys balancing capacity for FCR, aFRR, mFRR and RR on market terms, separately for the upward and downward direction. There are two procurement modes: a basic mode, with portfolio offers for each hour submitted a day ahead, and a supplementary 15-minute mode. Balancing energy and imbalances are settled in 15-minute periods instead of one hour, and the minimum size of a unit offering balancing services fell from 1 MW to 0.2 MW. On July 11, 2025 PSE joined PICASSO, which gives it access to aFRR resources of other connected TSOs. The cost of balancing capacity is recovered through PSE's tariff, so it is paid by all connected customers. ## What aFRR means for your software For a battery operator or an aggregator, aFRR means real-time control of the asset plus bidding and settlement on the balancing market. The software needs: - A low-latency control path. The setpoint arrives as a continuous stream, and the asset must follow it within the full activation time. The path from the TSO or balancing service provider interface to the inverters should not depend on a cloud round trip that can stall. - Setpoint arbitration. The same battery often trades on the day-ahead and intraday markets and holds an aFRR band at the same time. One component has to combine the setpoints from all sources, apply priorities and keep the committed aFRR band free of trading positions. - State of charge management. Upward activation discharges the battery and downward activation charges it, and activations do not have to cancel out over a day. The system has to keep enough energy in both directions for the whole commitment period. - Loss compensation. The TSO measures at the connection point, so conversion and transformer losses between the battery and the meter have to be covered. - Measurement records. Providers must pass prequalification and keep high-resolution measurements of requested and delivered power, because settlement and penalties are based on them. - Bidding and settlement: capacity offers per hour or per 15-minute period, energy bids, award handling and a reconciliation of requested versus delivered energy for every period. Writing the specification? Add aFRR to your requirements checklist Collect the terms your project touches and get their system requirements in one e-mail, ready for an RFP. aFRR requirements and the software component that handles them RequirementComponentWhat to check before you buy Follow setpoints within 5 minutesSite controller (EMS)Behavior when the cloud link is lostTrade and hold aFRR on one assetOrchestrator with source prioritiesHow conflicts and headroom are resolvedEnough energy for the commitmentState of charge plannerRecovery strategy after long activationsDelivery at the connection pointLoss compensationWhether losses are modelled per siteProof of deliveryTelemetry storeResolution and retention of measurementsRevenue and penaltiesSettlement modulePer-period reconciliation and audit trail ## From our projects For Global Green we are building the energy management system for battery storage sites, which runs on an industrial controller on site and sends data to the cloud. Its orchestrator combines setpoints from several sources, such as trading, aFRR and direct control, resolves conflicts between them and only then distributes the result across batteries. In July 2026 we added loss coverage: after conflict resolution the orchestrator increases discharge power and reduces charging power by a configured loss percentage, so that power committed for trading or aFRR is delivered at the grid connection point rather than at the battery terminals. Only configured sources are adjusted, the result never leaves the battery's operating range, and any truncation is logged. Since mid-2026 we have been migrating an existing aFRR pipeline into the new platform; as of October 2026 tests and the switchover are in progress. In September 2026 we completed the design of a controller that combines trading and aFRR on one battery, and its implementation is under way. ## 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. - [Day-ahead market](https://ordergroup.co/glossary/day-ahead-market/) The day-ahead market is a daily auction in which electricity for each 15-minute period of the next day is bought and sold. In Europe orders close at 12:00 CET and one algorithm sets prices for all coupled bidding zones. - [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. ## 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/) ## Sources 1. [Commission Regulation (EU) 2017/1485 establishing a guideline on electricity transmission system operation (SO GL), Article 3](https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32017R1485) - EUR-Lex 2. [PICASSO - European aFRR platform](https://www.entsoe.eu/network_codes/eb/picasso/) - ENTSO-E 3. [Ocena wpływu reformy rynku bilansującego (assessment of the balancing market reform)](https://www.ure.gov.pl/download/9/15866/Ocenawplywureformyrynkubilansujacego.pdf) - URE 4. [Dziś wchodzi w życie drugi etap reformy Rynku Bilansującego](https://www.ure.gov.pl/pl/urzad/informacje-ogolne/aktualnosci/12002,Dzis-wchodzi-w-zycie-drugi-etap-reformy-Rynku-Bilansujacego.html) - URE Paweł Zieliński reviewed this entry. Ask how it applies to your project. [Ask an engineer](https://ordergroup.co/contact-us/) ## FAQ ![Paweł Zieliński](https://ordergroup.co/media/images/Pawel_p3bY6z4.format-webp.webp) Paweł Zieliński Co-founder & Business Owner [Talk to an engineer](https://ordergroup.co/contact-us/) ### What is the difference between FCR, aFRR and mFRR? FCR reacts locally to frequency within seconds and stops the deviation. aFRR follows a setpoint from the TSO's controller and restores frequency within minutes (5 in Poland). mFRR is activated by instruction and takes over larger or longer imbalances, with up to 12.5 minutes to full activation in Poland. ### Can a battery provide aFRR and trade on the market at the same time? Yes, if the control software reserves the committed aFRR band in power and energy and gives the remaining capacity to trading. This needs one component that arbitrates between setpoints from different sources. ### Can a small asset take part in aFRR in Poland? Since June 14, 2024 the minimum unit size on the balancing market is 0.2 MW. Smaller assets can be pooled by an aggregator, and each unit has to pass PSE's qualification before it can offer reserves. ### What is PICASSO? PICASSO is the European platform for exchanging aFRR balancing energy between TSOs, live since June 1, 2022. PSE joined it on July 11, 2025. Building a system that depends on aFRR? 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.