Energy from restaurant waste
The plant – constructed by BEKON as the general contractor – utilises the batch fermentation principle to produce biogas under anaerobic conditions. Fermentation takes place in tunnels, with offset feeding and emptying ensuring continuous energy production. “This form of batch operation has proven to be particularly robust and reliable over the last three decades,” em-phasises BEKON project manager Matthew Cox. “The low internal energy consumption makes such plants particularly efficient, and the material can be fed into the tunnels in stackable form.” The plant is designed to process around 13,000 tonnes of bio-waste per year, which is collected separately in the region. It was commissioned, for example, using restaurant waste from neighbouring Split. Previously, this waste had to be transported by lorry to Zagreb – a five-hour journey.
Data centre with a green energy concept
Opposite the four fermenters are four further tunnels for composting the digestate. The fully automated tunnels are not only equipped with underfloor heating but also with ventilation as well as irrigation and allow for complete process control with the effect that the natural com-posting process can be accelerated from over twelve months to around two months with mini-mal labour. The end result is high-quality compost that acts as a natural soil improver. “When used in agriculture, it thus contributes directly to better crop yields and, consequently, to the cultivation of new food – a completely closed cycle,” explains Cox delightedly.
The waste heat generated during the conversion of biogas into electricity is not lost, but is also utilised as an energy source. The same will be done with the heat generated by the data cen-tre’s servers. Together with battery storage systems, the biogas plant and data centre are thus set to form a particularly sustainable energy park. “INOVAPRO uses sustainable energy genera-tion to create much-needed computing capacity. In doing so, they are directly tackling two ma-jor challenges of our time – and they have developed a truly impressive concept to achieve this, that serves as a model not only for Croatia,” Cox is certain.
One shift per day on five days a week is sufficient for the efficient operation of the plant. In ad-dition to BEKON, other companies within the Eggersmann Recycling Technology were also in-volved. Eggersmann Anlagenbau GmbH provided support with the planning and an Eggersmann TERRA SELECT T 50 trommel screen is being used to remove impurities from the finished com-post.
Flagship project for infrastructure development
The innovative Green AI project of INOVAPRO is to 80 % funded by the European Union and forms part of the country’s reconstruction and resilience plan. The plan is a response to the con-sequences of 2020. At that time, the COVID-19 pandemic as well as two particularly severe earthquakes in Petrinja and Zagreb had hit the country – which is heavily dependent on tourism – hard. The project now aims not only to create jobs outside the tourism sector, but also to make the country’s infrastructure more independent in terms of digitalisation and energy sup-ply. At the same time, the data centre is intended to prevent the brain drain of skilled workers. It is operated by INOVAPRO. The engineering firm, which specialises in sustainable solutions – such as heat pumps and photovoltaic systems – is thus expanding its business activities. The driv-ing forces behind INOVAPRO and Green AI are Sonja and Ante Čikotić. Ante Čikotić is well known in Croatia as one of the prominent promoters and opinion makers of the post-fossil transition in the country, while his wife Sonja Čikotić is a recognized expert in European Union funds and public procurement.
As the investment supervision engineer responsible at INOVAPRO, Ivo Grabovac highlighted the excellent collaboration with BEKON: “I would like to take this opportunity to express my thanks to the entire team who managed the project on site and did an outstanding job.”
