Austrian energy companies are increasingly helping to expand the hydro power capacities in the Balkans. On the River Ugar, which today marks the border between the Federation of Bosnia-Herzegovina and the Republic of Srpska, the Novakovici runof- river power plant has been delivered by a subsidiary of the Carinthian utility company Kelag, InterEnergo. In a normal year, the high-pressure plant, which with turbines from the Austrian manufacturer Gugler achieves an installed power output of around 5.75 MW, delivers 18.5 GWh of power. Around 6,000 households can therefore be supplied with clean power from the plant.
For a number of years now, Kelag has been asserting itself extremely successfully on the international stage. In particular the countries of the former Yugoslavia, Serbia, Bosnia and Herzegovina, Kosovo and Montenegro, have become the target of the company's strategic focus. Several power plants have now been constructed with Inter- Energo, which originated in Slovenia and is today a fully owned subsidiary of Kelag. This includes the Novakovici power plant on the River Ugar in Bosnia-Herzegovina, for which InterEnergo has had a preliminary project in the pipeline for a number of years. For Kelag itself, such projects provide the opportunity for it to demonstrate its own great in-house expertise when it comes to hydro power. Starting with the project management, the construction planning and the site management right through to the planning of E&M, the Kelag power plant team took the lead.
Records from the Communist Era
'We started the planning work back in 2010. And the tendering process and the awarding of contracts were accomplished in the same year. We really did put all hands to the pump,' says the Kelag project management team on reflection. The primary basis used for drawing up the plans was water course records that were over 20 years old. The records dated back to the former Yugoslavia, but they had been drawn up extremely diligently and meticulously – and therefore fulfilled their purpose perfectly. 'The line of the waterway was not only meaningful: It was also interesting because it bore scarcely any comparison with any bodies of water here in Austria. Accordingly, volumes ranging from zero up to enormous quantities could be anticipated. This made the process of designing the machines a real challenge,' say the experts from the Kelag power plant team.
By contrast, the location for the water catchment almost chose itself. It was to be constructed slightly below the point where the River Ilomska flows into the River Ugar. The plant was fundamentally constructed as a diversion power plant. The water for driving the turbines is captured at a side weir which is intended to guarantee operation that is controlled by the level of the water. Following the weir structure, an extremely largescale triple-chamber sand trap was constructed and this ensures the most effective removal of sand possible.
The project managers from the Carinthiabased company Kelag said: 'The criterion here was to bring the size level of desanding down to less than 0.3 mm. Finally, these waters here are really full of a large amount of debris due to the hydrology – and the priority was very much to protect the turbine rotor.'