Hydropower plant in Serbia

Recently completed on the River Lim in south-western Serbia lies a small hydroelectric power plant designed to cover the electricity needs of the town of Priboj and its environs. Construction of the associated dam required the full range of MC’s expertise in concrete technology.

Accounting for a share of about one third of electricity production, hydropower is already one of Serbia's most important energy sources. So far, this sector has been dominated by large plants generating in excess of 10 MW. However, in order to fully exploit the potential that exists, Serbia is moving more towards small hydropower plants as a solution for the medium to long term.

 

One such in Priboj, 250 kilometres southwest of the Serbian capital Belgrade, had been on the planning horizon for a decade. Although energy assessments and the building permits had already been issued back in 2012, it needed an additional environmental study commissioned by the Serbian state government – which asserted no negative impact on the environment – to dispel the doubts of local residents. Construction of the 46-metre-high dam of the small hydropower plant finally began in September 2018. The plant's output, with a flow rate of around 165 m³ of water per second, amounts to 7.9 MW per year. The facility was completed in July 2021. Hidro Tan d.o.o. was commissioned to build the structure, with the concrete being supplied by Beton komerc d.o.o. Both these Belgrade-based companies had already had positive experience of MC's advice, products and customer service in other projects. Right from the start, therefore, MC’s expertise in concrete technology was regarded as a known and reliable factor.

Robust concretes for summer and winter

The cement mix for the dam had to be formulated to ensure crack avoidance. Following extensive trials on the part of MC, C 25/30 and C 30/37 XF2 concretes were specified in the project planning. However, the real challenge lay in the weather conditions prevailing at the location: Hot, dry summers are just as common in the region as harsh, frosty winters. It was essential to maintain consistent construction progress throughout the year. Hence, high-performance superplasticiser MC-PowerFlow 5695 based on the latest MC polymer technology, and Centrament Retard 370, a setting retardant particularly suitable for high fresh-concrete and ambient temperatures, were used in summer. And in winter, the contractor was able to rely on the likewise PCE-based superplasticiser MC-Power-Flow 3100 for high-flow concretes in combination with Centrament Frost, a chloride-free antifreeze concrete admixture for cold concrete placement.

 

By final completion in summer 2021, around 30,000 m³ of concrete had been successfully installed, with MC's concrete admixtures ensuring smooth project progress throughout the three-year construction period, summer and winter alike.