For the RES Serbia portal, within the new column “Member Speaks”, Aleksandar Marjanović, Solution Engineering Team Leader in Siemens d.o.o. Belgrade’s Smart Infrastructure business, writes about the crucial role of battery energy storage systems in the energy transition.
It is almost impossible to imagine even a moment without electricity. Although it is an inseparable part of our daily lives, we rarely stop to consider that the power system as a whole represents one of the most complex technological achievements humanity has ever created. From modest installations at the beginning of the 20th century, limited to lighting urban areas, electrification has evolved into a fundamental pillar of modern society. Siemens technologies have been part of key infrastructure projects in Serbia that shaped the development of the domestic economy and improved citizens’ quality of life. The company participated in the commissioning of the first public thermal power plant in Dorćol back in 1887, equipped pioneering hydropower plants in Užice, Vučje, Gamzigrad, and Ivanjica, and contributed to the development of telecommunications infrastructure by introducing the first automatic telephone exchange in Novi Sad.
Despite the speed and scale of development, the very concept of how power systems function has not changed significantly – the main challenge has remained the strict correlation between electricity consumption and production, along with resilience to failures, while solutions for storing significant capacities were rare. Centralized generation and the interconnection of neighboring countries’ power systems gradually shifted the focus away from storage toward precise planning and regulation of generation capacities.
The Evolution of Power Systems
A major shift in the concept and functioning of power systems is happening in the 21st century. Environmental impact has come to the forefront, as humanity’s demand for energy increasingly affects the planet. With technological progress and new market models, emphasis is placed on the green transition – using electricity from renewable sources with maximum efficiency and optimization, aligning demand with the sustainable resources available at any given moment.
Naturally, such a profound change, though gradual and carefully planned, brings numerous technical and regulatory challenges. This has once again highlighted the need for system reserves in periods of reduced generation, as well as additional capacity to store energy when available resources exceed consumer demand.
Battery Energy Storage Systems (BESS)
Technological solutions for electricity storage have been intensively developed and improved in recent decades, with battery systems currently representing the most promising technology. This is confirmed by the fact that in 2025 alone, newly installed battery storage capacity in the EU reached 27.1 GWh, raising the total operational capacity to 77.3 GWh. The largest share was installed in standalone large-scale battery facilities, but in recent years, a particularly significant scenario has been the combination of photovoltaic plants and battery storage in so-called hybrid power plants. In the past year, such systems accounted for around 15% of newly installed BESS capacity in the EU. Operating a battery storage system of adequate capacity alongside a photovoltaic plant provides great flexibility and optimization in market conditions unfavorable to electricity prices, which typically coincide with peak daytime solar generation. In such scenarios, the ability to temporarily allocate electricity produced by solar plants into storage effectively “shifts” its sale to a more favorable period, often providing sufficient economic incentive for investment in battery systems. An additional positive effect is seen on the grid side, as energy is stored near generation units during peak production, reducing congestion and relieving system elements. Economic models for standalone battery storage, usually of large capacity, are more diverse and largely depend on regulatory frameworks and the specific market. Common examples include providing ancillary services and supporting system operators with rapid responses to disturbances, either by absorbing excess electricity or injecting additional power.
It is precisely this technical complexity that has driven Siemens to rapidly expand its portfolio of products for such solutions in recent years. In addition to new connection facilities with state-of-the-art protection systems within the SIPROTEC portfolio, a crucial element is reliable and high-performance power infrastructure, including substations and switchgear. However, the key component in facilities such as battery storage, photovoltaic, or hybrid plants are advanced controllers, whose functionalities determine the efficiency of all subsystems as well as the system services the facility can or must provide to the market. For this reason, Siemens’ SICAM Power Controller has become one of the most sought-after solutions worldwide, offering nearly all functions recognized by system operators.
It is difficult today to predict with certainty which technologies will lead the next phase of power system evolution, but the direction is clear: systems will need to be more flexible, highly controllable, and capable of balancing generation, consumption, and storage in real time. Siemens continues its tradition of more than a century, developing solutions that not only generate and transmit energy, but also ensure it is available at the right moment.
Through solutions such as the SICAM Power Controller, which integrates the control of power facilities and renewable energy sources with storage systems, Siemens enables its customers and partners to transform flexibility into tangible market and technical value.
