Battery Energy Storage Systems (BESS) are among the most important building blocks of the energy transition. They balance out fluctuations between electricity generation from wind and photovoltaics and actual consumption. High-performance transformers play a decisive role in connecting them to the grid. With every doubling of installed BESS capacity, economies of scale, cell prices, and system performance all improve – the industry is developing rapidly.
How does a battery storage system work within the power grid?
A BESS charges electrical energy during periods of surplus – for example, around midday during high PV feed-in – and discharges it again when needed. Inverters convert the direct current from the battery modules into alternating current; a distribution or power transformer then raises the voltage to the respective grid level. This allows frequency, voltage, and power flows to be actively stabilized.
Key Characteristics at a Glance
- Fast response time in the millisecond range for frequency regulation
- Scalable storage capacities from a few kWh to several hundred MWh
- Modular design using container or cabinet-based solutions
- Integrated fire protection and climate control
- Connection via specially dimensioned BESS transformers with high cycling durability
- Lithium-ion cells are the current standard
- Alternatives such as sodium-ion and redox-flow are gaining importance
Frequently Asked Questions
What role do transformers play in BESS projects?
They connect the inverter to the medium- or high-voltage grid and adjust the voltage precisely. Because of the high number of load cycles and fast response requirements, BESS transformers are designed to be particularly robust and with an adapted efficiency profile.
What are typical use cases for BESS?
Typical application areas include primary frequency control, peak shaving, self-consumption optimization for industrial customers, grid connection of wind and solar farms, and island grids. BESS are also used in uninterruptible power supplies for large data centers.
What service life do modern battery storage systems achieve?
Typical values are 10 to 15 years of calendar life at 6,000 to 10,000 full cycles. High-quality systems with active thermal management and an intelligent charge-discharge strategy can significantly exceed these figures.
What should be considered when choosing a BESS site?
Important factors include proximity to the grid connection point, sufficient space for the container and transformer, suitable fire-safety clearances, low noise emission levels, and a favorable microclimate for cooling. The permitting situation and the connection to the grid operator’s higher-level control system also play a decisive role.
Designing a BESS project requires transformers that are precisely matched to the application. Contact us – together we will develop the right solution for you.