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Battery Energy Storage Systems: grid stability and reliability

Enabling renewable energy with battery energy storage systems

Renewable energy’s market share is growing fast worldwide, with the goal of outgrowing fossil fuels and embracing CO2-neutral energy supplies. In the EU alone, renewables are expected to generate 42.5% of all energy by 2030. Energy storage enables all this green electricity to be used efficiently, ensuring electricity grids remain stable. With the increasing share of renewables in the Polish power system, it is also necessary to escalate the potential for electricity storage. 

We at BayWa r.e. are globally active in developing and realising wind, solar, as well as energy storage projects. Our project development experience and technical expertise give us a comprehensive understanding of local requirements for battery storage systems (BESS), both as standalone projects, as well as integrations that co-locate solar PV and wind farms with BESS technology.

What are Battery Energy Storage Systems (BESS)?

The success of energy transition depends on the use of smart combinations of sustainable technologies. Battery energy storage systems are one of them – and the missing piece that allows us to make the most out of clean energy sources.

Battery storage technology is versatile and powerful. Large-scale stationary storage systems ensure sufficient renewable energies are always available at the right time. Placing BESS strategically across the power grid helps reduce the need for grid expansion by making better use of existing infrastructure. 

Battery storage, coupled with or without renewables, creates flexibility and electricity supply security.

How does storage work?

BESS are rechargeable batteries that enable energy from many sources, such as renewables - solar, wind, to be stored and then released when the national grid requires power. 


Batteries are grouped and housed adjacent to inverters.


Convert the DC current from the batteries to the AC current of the national energy market.


Transformers increase the output voltage of the BESS inverters to the level of the grid voltage.


Underground cables connect all the components.


Electrical substation serves as a gateway to connect to the national energy market.

Renewable Generation

Battery projects can be either stand-alone projects or may be connected with renewable generation sources.

Battery energy storage systems (BESS) enable more renewable energy to be fed into the grid. BESS can answer to demand peaks and thus have a dampening effect on energy prices on the electricity exchange as well as reducing the load on the grid.

Site Storage

If required, spare parts are stored in containers or appropriate buildings, protected and by the manufacturer's specifications.

Batteries (e.g. Lithium-Ion)

are housed in containers to easily wire them together and protect from the weather conditions. The containers are equipped with the HVAC (Heat Ventilation and Air Conditioning unit) to keep them at the perfect temperature in winter and summer. Every BESS is also equipped with a variety of safety devices, including fire detection and fire protection equipment. DC Disconnect Switch allows system to be disconnected remotely or manually when needed. BESS Controller controls the charging and discharging of batteries fully automatically based on the technical parameters and market signals.

In order to maintain the grid frequency of 50 Hz, there must always be a balance between generation and demand in an electrical system. As soon as one or the other predominates, deviations from the target frequency would occur. To prevent this happening, there is what is known as frequency control power, which is used when generation and consumption are not in balance. BESS can provide these so-called ancillary services for frequency control quickly and cost-effectively, thereby ensuring security of supply.

FAQs about Battery Energy Storage Systems

  • What does a BESS development look like?

    BESS facilities consist of battery storage systems and electricity grid connection equipment. The power from the batteries is then connected to an onsite switchgear room that is housed within a green building similar to a storage container which would then be connected to a substation via underground cables. The facility is monitored and secured with fencing.


  • What are the benefits of BESS?
    • BESS, especially together with renewables responds to the climate crisis and the urgent need to decarbonize and stabilize energy supply, underpinning the move to a cleaner environment and a greener economy. 
    • BESS facilities help to provide a constant supply of renewable energy to homes and businesses in local areas, as well as securing our energy infrastructure.During periods of low demand, battery storage systems efficiently retain excess electricity for release during peak times, mitigating grid strain and fostering long-term cost reduction for end-users.
    • Batteries also underpin the country’s ability to further our security of supply capabilities. These systems not only enhance stability and flexibility within the electricity grid but also provide resilience to the energy market amidst unpredictable global events and market fluctuations. 
  • Why is the flexibility of storage solutions so important?

    The production of solar and wind energy varies depending on the weather. As renewables’ share of overall energy mix increases, grids must ensure stable supply even at peak times. Storage solutions offer crucial flexibility: they store power in times of low demand, releasing it again when demand is high.

  • Are BESS developments noisy?

    Noise Assessments are conducted at an early stage to inform the scale and design of our BESS developments. This ensures the avoidance and mitigation of unacceptable noise levels in the immediate surrounds and to ensure full compliance with the planning and operational conditions which govern the operation of BESS projects.

  • Are BESS facilities safe?

    Safety at BESS facilities, in particular fire safety is something we consider during each stage of our development, design, and procurement activities. Each battery storage container is fitted with internal sensors that detect smoke, high temperatures, and flammable gasses. Battery storage systems used by BayWa r.e. have the highest safety standards on the market. Specialised fire suppression systems are part of all battery storage systems and in the very unlikely event of a fire the battery will be immediately shut down and fire extinguishing measures are automatically released.

  • Which technologies does BayWa r.e. use for large-scale battery storage?

    As storage devices, lithium-ion (li-ion) batteries have a high energy density and lose little capacity with frequent charging. About 90% of stored energy is recovered and used again. Li-ion batteries are scalable; systems can be of any size, thanks to a modular design. They’re also more widely available, therefore more cost-efficient. 
    Our development teams are always exploring new technologies. We’re in close contact with manufacturers to diversify our technology portfolio. Sodium-ion batteries, for example, have potential to compete with li-ion. Realising this potential represents a big step forward, making batteries less resource-intensive and with more localised value chains. 

  • How important are storage projects for the success of the energy transition?

    Very! Large-scale BESS reduce need for expensive grid expansions. By combining high efficiency and fast reactivity, they balance short-term differences between supply and demand. They also enable renewables to be integrated into the electricity grids more reliably and widely. In future, we’ll see a diversified landscape of storage solutions used to enable the move to net zero.

How We Can Help You

  • We structure projects individually, coordinating development and implementation from a single source.
  • Our experienced team reviews existing income streams on your behalf for the best achievable revenues.
  • We undertake the planning, technical design, and construction of both our own and third-party projects.
  • State-of-the-art maintenance plans, 24/7 monitoring, and on-site services ensure smooth operation for your battery storage system as well as wind and solar.

Why partner with us?

BayWa r.e. expertise covers the whole value chain; from planning and financing to implementation, safe operation, and marketing.

Battery storage systems help advance the energy transition while securing a stable cash flow for decades.

Years of experience in wind and solar let us operate renewable energy installations as profitably as possible. BayWa r.e. experts can handle everything from construction to contracts and permitting. If you’ve already invested in renewables, BESS will further diversify your portfolio and generate additional revenue streams.

Contact us to learn more about the possibilities of large-scale battery storage.

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