International industrial services provider Bilfinger has completed the implementation of a new heat accumulator for energy company Utilitas. With a capacity of 1,100 MWh, it is Estonia’s largest heat storage facility to date. As such, it will support the expansion and security of the region’s district heating supply. On Friday, Utilitas officially opened the new facility at their site in Tallinn’s Väo energy complex.
Bilfinger was responsible for the full implementation scope and has provided all design, engineering, prefabrication and installation services. After high-quality prefabrication at Bilfinger’s workshop in Grodek, Poland, the accumulator was assembled on site using the spiral method – a unique approach that delivers maximum efficiency. It now has a final height of 42 meters, a diameter of 26 meters and a volume of 20,700 cubic meters. The accumulator is designed to help balance daily fluctuations in district heating demand and supports the city’s transition toward lower-carbon energy supply.
“In today’s energy industry, where flexibility and efficiency are increasingly important, storage plays a very important role. This allows for a better response to the variability in consumption, increases production efficiency and security of supply of the entire system. Storage technology is equally necessary in both electricity and heat networks,” says Priit Koit, CEO of the Utilitas Group.
Thierry Burki, President Segment Central Europe at Bilfinger, commented: “We are glad to be supporting Utilitas in expanding their thermal infrastructure, thereby contributing to Estonia’s long-term decarbonization and energy-security goals. By leveraging our market expertise, unique assembly method and proven storage technology, we can tailor each accumulator to the specific needs of our customer, the location and the heating grid.”
The collaboration with Utilitas is the result of Bilfinger’s acquisition of Rodoverken in December 2024 and an example of the added value Bilfinger can offer through targeted M&A activities in core and adjacent markets. The acquisition allowed Bilfinger to integrate Rodoverken’s strong mechanical capabilities and geographical coverage with its own extensive heat storage and distribution experience. Thus, Bilfinger further expanded its service portfolio and regional capacities, strengthening its position in the rapidly growing European Thermal Energy Storage Market.
The new heat storage solution is an atmospheric accumulator based on the proven Hedbäck principle, which reduces maintenance efforts and allows hot water to be stored at temperatures up to 98 degrees Celsius.
