IN Brief:
- The Herby battery in Silesia has a power rating of 5 MW and a nominal storage capacity of 10 MWh.
- Entrix is responsible for market trading and optimisation, but the installation has not yet completed balancing-services qualification.
- R.Power links the operating milestone to a wider European battery pipeline of around 1.6 GW/5.8 GWh; future sites are at different development stages.
R.Power has energised its first standalone battery energy storage project in Poland, the 5 MW/10 MWh Herby installation in Silesia. The plant has entered operation, and Entrix is responsible for trading and optimising its electricity-market activity. Qualification to provide balancing services is continuing. Grid connection and commercial operation should therefore not be taken as evidence that Herby has already been authorised to deliver every frequency-restoration or reserve product.
Herby is located in Lubliniec county in the Silesian region. Its published ratings distinguish power, measured in megawatts, from stored energy, measured in megawatt hours. A 5 MW discharge at the nameplate energy rating corresponds mathematically to two hours before accounting for operating limits and losses. Actual delivery duration depends on the usable state-of-charge window, efficiency, battery condition and dispatch requirements, none of which can be established solely from those two ratings.
The installation began construction in the fourth quarter of 2025. R.Power reports that the project obtained a long-term agreement through Poland’s December 2024 capacity-market auction and secured a supplementary capacity-market contract in September 2026. These agreements provide a different commercial mechanism from trading electricity or responding to short-term balancing instructions. A contracted capacity obligation may require availability at specified times, while market optimisation determines when charging or discharging is commercially and technically appropriate.
Entrix is responsible for managing trading and optimisation across the relevant markets. Its work has to reconcile several potentially competing uses of stored energy. Charging when prices are lower and discharging when they are higher can earn an energy-market spread, but retaining charge and discharge headroom may also be necessary for capacity obligations or future reserve commitments. Frequent cycling adds operational considerations involving usable energy, thermal management and battery degradation. The operator must therefore plan around the physical limits of the equipment rather than optimise prices in isolation.
A utility-scale battery interfaces with the grid through power conversion equipment that changes battery direct current into synchronised alternating current during discharge and reverses the process during charging. The conversion system and plant controls determine the rate and direction of power flow, while protective equipment and site connection conditions constrain what can be injected into or taken from the local network. Although R.Power has confirmed energisation, its announcement does not publish detailed inverter specifications, a round-trip efficiency figure or performance results for Herby, and these should not be inferred from the headline ratings.
For balancing services, the technical and commercial checks are more specific than simply being connected to the grid. Relevant operators must be able to measure response, receive appropriate instructions and demonstrate that the plant can deliver within the requirements of the reserve product. A battery that has started energy-market operation may be capable of the necessary response but still require testing, telemetry integration or accreditation before it can submit qualifying offers. R.Power explicitly identifies that process as ongoing at Herby.
R.Power describes Herby as having an asymmetrical battery design, but has not disclosed detailed charge and discharge limits that would explain how that arrangement is implemented. The term should not be used to infer that the site can continuously export above its stated 5 MW rating or that all 10 MWh can be delivered under every operating condition. Available energy, inverter capability, thermal limits and reserved capacity obligations may each constrain a trading instruction, and a public performance dataset for the plant has not been provided.
Herby is the first standalone storage installation in R.Power’s portfolio to reach operation. The company cites an advanced European battery pipeline of approximately 1.6 GW and 5.8 GWh, including Jedwabno, Dzięgielewo and Gdańsk in Poland and Scornicești and Studina in Romania. Those amounts combine projects at different stages and are not additional capacity already delivering power. Equipment placement at Jedwabno and a connection contract at Studina are separate milestones rather than evidence of energisation at those sites.
Poland’s battery sector combines energy trading, long-term capacity-market commitments and the developing market for fast-response balancing resources. Storage can move electrical energy from one period to another and change grid import or export quickly, but any discharge consumes a finite energy inventory that must eventually be replenished. At Herby, the relationship between a 5 MW power rating and a 10 MWh nominal energy rating illustrates why a market operator has to manage both megawatts and operating duration. The achievable revenue mix depends on market prices, dispatch decisions, contractual availability and the outcome of reserve qualification.
R.Power has confirmed a physical operating milestone at Herby, with an optimisation partner in place and capacity-market agreements secured through earlier auctions. The company has not supplied detailed operating results or a date for completion of qualification for balancing services. Future updates on technical accreditation, delivered reserve energy and performance will establish how much additional grid flexibility the 5 MW asset provides beyond its existing commercial operation.
