The construction of gas infrastructure in the Baltic Sea is entering a phase of intensified work. This is a technically demanding and operationally complex stage of the project. In Górki Zachodnie, preparations have begun for one of the key elements of Poland’s FSRU programme: the drilling of an over one-kilometre-long microtunnel that will connect the onshore and offshore sections of the infrastructure without disturbing an environmentally valuable and popular coastal area.
The planned terminal in the Gulf of Gdańsk is expected to provide an annual capacity of 6.1 billion cubic metres of gas. It will strengthen Poland’s ability to import liquefied natural gas and improve the security of gas supplies not only for the domestic market, but also for other countries in the region.
A floating LNG terminal in the Gulf of Gdańsk
The FSRU programme involves the construction of infrastructure for receiving liquefied natural gas transported by sea, storing it, regasifying it and transmitting it into the national gas transmission system. The central element of the project will be a floating storage and regasification unit, or FSRU — a vessel that will function as an LNG terminal.
Gas received in the Gulf of Gdańsk will be transported to the transmission network through a subsea pipeline. The section running beneath the land and coastline will be placed inside a microtunnel.
“Currently, we are in the phase of the greatest intensification of works, both on the onshore part of our project and at sea. We have a TBM drilling machine that will excavate the microtunnel, where we will then install the subsea gas pipeline. In the coming days, we are also planning for vessels to depart and prepare test sites for piles, so that from June we can begin driving the final piles on which the jetty will be built — the quay where the FSRU unit will be moored,” said Maciej Wawrzkowicz, offshore FSRU project manager at GAZ-SYSTEM, in an interview with Newseria.
TBM machine delivered to Górki Zachodnie
On 30 April, the TBM machine head arrived in Górki Zachodnie. From mid-May, the machine is expected to begin work at the construction site. The use of this technology allows the works to be carried out using a trenchless method.
The machine’s task will be to drill a tunnel beneath the coastal forest, dunes, beach and the seabed of the Gulf of Gdańsk without interfering with the surface. In the case of Górki Zachodnie, this means passing beneath an area of high environmental value while maintaining access to the beach during construction.
“Microtunnelling is the safest way to pass beneath an obstacle. GAZ-SYSTEM, as the contracting authority, planned this method as part of the project in order to protect both the people using the local infrastructure, including the beach, and the natural environment. The microtunnel allows for a trenchless crossing beneath the obstacle,” explained Łukasz Radomski, deputy contract director at the Gap Insaat – Fabe Polska – Unitek Insaat consortium.
According to Paweł Ciomek, deputy construction manager at the same consortium, the TBM machine enables underground trenchless crossings. Its main component, the cutting wheel, breaks up the excavated material at the tunnel face. The material is then transported by slurry to the rear of the tunnel, to the launch chamber, where it is processed and disposed of.
An 1,100-metre tunnel beneath the coast
Before drilling could begin, it was necessary to prepare the detailed design documentation, construct the launch chamber and secure the ground. This stage also included defining the route and depth of the tunnel.
“The works related to preparing the entire execution documentation took around eight months. At this point, all project approvals have been obtained, which allowed us to order the necessary concrete elements and the machine. We are now beginning preparations for installing the entire TBM machine in the launch chamber,” said Łukasz Radomski.
According to Maciej Wawrzkowicz, the machine will be positioned within two weeks and will then begin its approximately 1,100-metre route towards the sea. The tunnel will be one of the key infrastructure elements of the entire project.
The microtunnel will be approximately 1,100 metres long and around 2.5 metres in external diameter. It will be built from prefabricated reinforced concrete pipes, which will form its load-bearing structure and ensure tunnel stability. Inside the tunnel, a subsea gas pipeline will be installed, connecting the terminal with the national transmission system.
Depending on ground conditions, the drilling rate may range from a dozen to several dozen metres per day.
Offshore works to accelerate in the coming months
According to GAZ-SYSTEM, drilling the microtunnel will take around three months. After that, the tunnel will be secured and then filled with water in a controlled manner. The TBM machine will be recovered at sea, approximately 800 metres from the shoreline, in the area known as the exit pit. The next stage will involve preparing the entry chamber so that it can be transformed into an assembly corridor for previously prefabricated and welded sections of the subsea gas pipeline. These sections will then be inserted from the land side towards the sea.
“The casing pipes of the microtunnel will be added one after another and pushed forward using hydraulic jacks to ensure the continuity of the tunnel. At the critical moment, the force at the rear of the tunnel will reach 5,000 tonnes to push the pipes forward,” said Paweł Ciomek. “A key element is ensuring the correct pressure at the front, near the cutting wheel, because this pressure will guarantee the stability of the excavation and prevent soil from collapsing into the tunnel.”
The delivery of the TBM machine marks the transition to the next stage of the FSRU investment and the start of the main construction works in the offshore section. In the coming months, works will be carried out simultaneously on land and at sea.
“This construction season is very important for us to ensure the success of the offshore part of the project and to achieve synergy between the implementation of its three components,” said Maciej Wawrzkowicz.
Three components of the FSRU programme
The FSRU terminal project has been divided into three components: the offshore section, the onshore section, and the segment covering the floating unit and business model. This division allows works to be carried out in parallel.
In addition to the microtunnel, offshore works include preparations for pile driving under the jetty structure located about 3 km from the shore, as well as the construction of technological platforms and installations for LNG handling. The onshore part of the investment includes the construction of around 250 km of gas pipelines connecting the coast with central Poland.
“The implementation of the offshore part of the FSRU programme is part of the completion of the company’s broad investment portfolio related to the concept of the Northern Gateway, which aims to create a new corridor for natural gas entering our system from north to south,” Wawrzkowicz noted.
A second major maritime gas import point for Poland
The FSRU terminal in the Gulf of Gdańsk will become another major maritime gas import point for Poland, alongside the LNG terminal in Świnoujście. Together, the two facilities are intended to increase Poland’s import capacity and improve the flexibility of the transmission system, including flows towards southern Poland and neighbouring countries in the region.
The launch of the terminal is planned for the turn of 2027 and 2028.
The project has been included on the European Union’s PCI list — Projects of Common Interest — which covers investments of key importance for energy security and the integration of the EU energy market.
“The moment I am most looking forward to is when we integrate the entire installation from an infrastructure perspective. However, this is still several months away, because there is a great deal of work ahead before the subsea gas pipeline is connected with the technological installation on the jetty. This will allow us to achieve full mechanical integrity of our future technological infrastructure,” said Maciej Wawrzkowicz.
