IN Brief:
- Construction began on 15 October after the separate March 2026 contract award.
- The 20 MW/100 MWh design has a nominal five-hour energy-to-power ratio.
- Section 11a EnWG allows residual market activity when capacity is not needed for the agreed network service.
MaxSolar and distribution network operator N-ERGIE Netz have marked the start of construction of a 20 MW/100 MWh battery at Winterschneidbach, near Ansbach in Bavaria. The facility is planned beside N-ERGIE Netz’s substation, with a 20 kV connection to the local distribution system. It is designed to provide a contracted network-support service during periods when variable renewable generation strains the distribution infrastructure.
The 15 October 2026 construction start follows a distinct procurement decision in March, when N-ERGIE Netz selected MaxSolar after a tender attracting more than 20 bidders. Construction moves the scheme beyond contract award, but neither the battery nor its grid connection has been reported as energised. Installation, controls integration, network testing and commissioning must still take place before the contracted service can be delivered.
The specified 100 MWh of stored energy and 20 MW of charge and discharge power amount to a nominal five-hour energy-to-power configuration. That ratio indicates how long the energy rating would support a constant 20 MW output under simplified conditions. Actual duration at the grid interface will depend on inverter efficiency, operating reserves, usable state of charge and other limits. The partners have not published measured performance data for the unfinished installation.
A distribution network experiences the effects of solar generation differently from the transmission system. Photovoltaic installations connected to local feeders can export power back towards substations when production exceeds nearby demand. The resulting flows may constrain transformers, circuits or permitted voltage ranges. A battery charged at an appropriate location can absorb some of that output and discharge later when network conditions permit, shifting energy in time without requiring it to travel immediately through a constrained part of the system.
The substation location is relevant because charging and discharging must be scheduled where they can change flows on the constrained part of the distribution network. The proposed 20 kV connection provides the electrical interface for that exchange, but a nameplate rating alone cannot establish how much photovoltaic generation will be accommodated or how frequently local curtailment will be avoided. Those outcomes depend on the network’s physical limits, the contracted control conditions and the storage system’s state of charge when solar output rises.
Section 11a of Germany’s Energy Industry Act (EnWG) permits a network operator to procure the construction, management and operation of a third-party-owned storage installation through an open, transparent and non-discriminatory tender where the service is needed for efficient network operation. In this project, N-ERGIE Netz specifies the grid-supportive requirements. The provision also allows the third party to market capacity and energy when they are not required for the agreed network service. The partners have not published the detailed Winterschneidbach dispatch hierarchy, settlement rules or allocation of market revenues; it would be inaccurate to call the battery either an unrestricted merchant asset or a system permanently barred from electricity trading.
The facility will require bidirectional inverters, battery management, communications and electrical protection at the 20 kV interface. Charging at the wrong moment could worsen an existing local constraint, while discharge must be limited when downstream demand and circuit capacity cannot accommodate the power. Supervisory controls will therefore need to respond to the contractual network instructions as well as the battery’s temperature, voltage and state-of-charge limits. The published construction announcement does not identify the inverter manufacturer, protection settings or the full control architecture.
At 100 MWh, the battery is substantially larger in stored energy than the smaller distributed installations commonly used at individual commercial premises. Its purpose, however, is spatially specific. A battery can ease a bottleneck only where its connection and operating profile influence the constrained circuits. Network studies, operational data and post-commissioning measurements will be needed before claims about congestion reduction or improved renewable hosting capacity can be assessed quantitatively.
The companies describe Winterschneidbach as Germany’s largest battery project in this particular grid-supportive category under Section 11a, not as the country’s largest battery of any type. N-ERGIE Netz is the contracting distribution network operator, and MaxSolar was appointed after the competitive tender earlier in the year. A separate MaxSolar development at Waren has its own hybrid electricity arrangement and should not be confused with the Ansbach project. The new milestone at Winterschneidbach is a construction start only.
Site works now precede equipment installation, grid-interface commissioning and the first period of actual service delivery. Whether the five-hour configuration reduces congestion at the intended times will become clear only from dispatch and network data after energisation. The network-support contract provides the operating purpose and the construction notice confirms physical progress; neither supplies measured curtailment savings, operational availability or an in-service date.
