A contribution to the security of gas supply in the European Union

BENNING power supplies secure critical loads at the LNG terminal on the Croatian island of Krk, also known as the “Golden Island”.

The EU is considered the largest importer of natural gas in the world.*1 About a quarter of the EU’s energy consumption is currently based on natural gas, which amounts to a total demand of about 400 billion cubic metres. Only about 10% of gas demand is currently met by domestic gas production. In terms of energy security and competitiveness, diversification of supply sources is therefore a high priority.

The most important distribution methods to Europe are pipelines and the sea. The expedition takes place in the liquid (sea route) or gaseous (pipeline) aggregate state.

In order to better store and transport the natural gas by sea, it is cooled to about -162°C and liquefied. So-called “liquefied natural gas” (LNG) takes up about 600 times less volume. Once it arrives at the landing point by ship, it is gasified again and distributed via the gas networks in the same way as the gas that reaches Europe via pipeline.

The EU’s current LNG import capacity could cover around 40% of current demand, but only around 80 billion cubic metres of LNG were imported into the EU in 2021. This is partly because not all EU countries have access to a regional gas hub with a wide range of supplying sources, including LNG.

Developing the necessary regionally distributed LNG landing facilities can make the EU more resilient to possible supply disruptions from individual gas suppliers. This is because LNG can be sourced globally from many different supplier countries.
In addition to the strategic aspects, as with all infrastructure measures, economic viability is also of great importance. In the construction of LNG terminals, floating storage and regasification units (FSRUs) are a flexible and profitable alternative to pure onshore terminals. *1

Such an LNG terminal was commissioned in 2021 by the company LNG Croatia LLC on the Croatian island of Krk. The only facility of its kind in Croatia to date strengthens the security of gas supply, especially for the Central and South-Eastern European EU states.

On behalf of the general contractor, the Croatian BENNING subsidiary was responsible for the project planning, production and installation of the power supply system intended to protect the critical loads and also supplied the NiCd battery strings required to bridge blackouts.

The power supply system is located in the central control building on the landside part of the LNG terminal, which also includes the jetty head, the dolphins for the FSRUs and LNG tankers, the high-pressure unloading arms and the fire-fighting system.
The NiCd batteries placed on special racks that are housed in a battery room with a ventilation system that complies with safety standards.

The power supply system installed by BENNING is specially designed for use in harsh industrial environments such as the oil and gas industry. It guarantees an uninterrupted power supply to the critical loads of the LNG terminal 365 days a year, around the clock. These include, for example, the SCADA system and the LNG control stations. If these systems were to fail, the complete monitoring and control of the LNG terminal would be affected.

In order to eliminate this risk, the power supply system has a completely 1+1 redundant design. It is based on two identical UPS systems of the type ENERTRONIC I, each with a capacity of 30 kVA and an output frequency of 60 Hz. The ENERTRONIC I UPS complies with the highest UPS classification VFI SS 111 according to IEC / EN 62040-3 and thus offers maximum supply reliability.

Each UPS cabinet contains its own input and output transformer, rectifier, inverter and static bypass. It thereby fulfils all the technical specifications required by the customer.

A third cabinet, located between the UPS systems, accommodates the connection and distribution panel as well as the manual bypass. Each UPS system has a separate battery string consisting of 178 cells with a total capacity of 460 Ah. This ensures a bridging time of 240 minutes with an assumed load of 22 kW.

However, this static UPS system not only has the goal of supplying the connected loads with energy continuously and without interruption, but also achieves a significant improvement in voltage and frequency quality compared to the normal grid.

Highest quality required

Construction work on the LNG terminal’s control building began in May 2020. In parallel, the contracted EPC company (EPC = Engineering, Procurement and Construction) was looking for a reliable partner to manufacture and install the planned power supply system.

BENNING has well-established itself in the Croatian oil and gas sector over the past two decades with many successful projects. The company is considered a reliable business partner with high quality standards. Especially in the field of power supply, the company realised a large number of 110 V DC reference projects to its credit. These include, for example, power supplies for transformer stations or for use in the refinery sector.

Krešimir Kaurić

“We like to compare our UPS systems to a referee at a sporting event. It is essential that he is present, but it is best not to notice him.”

Krešimir Kaurić,
Head of subsidiary BENNING in Croatia

Accordingly, BENNING also received this request. After designing a possible solution, the Croatian subsidiary submitted a compehensive offer in November 2020. In addition to the economic aspects, the customer was convinced that the solution proposed by BENNING could fulfil all the desired technical requirements. The “Made in Germany” manufacturing and the availability of a local BENNING service centre also had a positive effect on the awarding of the contract. Although the robust power supply system is designed for a long service life, regular proactive maintenance contributes to increased safety and economical operation.

In the following 15 weeks after receiving the order, the detailed clarification of all technical parameters began, followed by the production of the power supply in the Bocholt factory. Delivery and installation took place and the power supply system went into operation soon after the installation was finished.

Security through proactive service

In the meantime, the LNG terminal in Omišalj has been in operation for more than a year and the first agreed proactive maintenance of the power supply was carried out by the BENNING service team in June 2022. A five-hour measurement of the battery capacities also took place within this framework. The globally positioned BENNING service organisation is not only available for planned maintenance processes. It also reacts quickly and reliably if a malfunction is imminent or actually occurs. For this purpose, it also relies on a long-term stock of spare parts.


Battery room with NiCd battery cells and employee with notebook
The 356 NiCd battery cells in the battery room with a total capacity of 460 Ah

Utilisation of the terminal increases daily

Against the backdrop of the current geopolitical situation, the capacity utilisation of the LNG terminal is continuously increasing. In the future, this could develop into a regional gas hub. An expansion of the LNG terminal is currently under discussion.

With this LNG project realised in Croatia, BENNING has once again proven that it is a reliable partner in the field of power supply for critical infrastructures. It supports its customers worldwide already during the planning phase and offers appropriate economic and technical solutions for an uninterruptible power supply. Decades of experience in engineering, manufacturing and installation guarantee trustworthy and sustainable quality.

Further Information

author/contact: Krešimir Kaurić
telephone: +385 1 6312 280

*1 Source: https://energy.ec.europa.eu/topics/oil-gas-and-coal/liquefied-natural-gas_en

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