The TENP pipeline system moving natural gas from the Netherlands to Switzerland and Italy will in future be reversible, i.e. the gas will be able to flow both from north to south and from south to north. The piping system at the Hügelheim compressor station, which controls gas flows along the TENP pipeline, will be modified as required for two-directional flow. The TENP flow reversal project is also part of the planned transition from L-gas to H-gas, which will help ensure the security of gas supply to Germany. This transition from L-gas to H-gas will allow the declining production of low-calorific L-gas to be replaced by new sources of supply and transmission routes for high-calorific H-gas. For TENP, these new sources of supply are located in southern Europe and north Africa.
The scope of work for this reversal project includes the installation of four additional DN 900 isolation valves complete with the connecting pipework on the premises of the Hügelheim compressor station. The project is part of Germany’s Gas Network Development Plan 2015 and is also funded by the EU as a Project of Common Interest (PCI).*
TENP gas transmission system
The TENP (Trans-Europa-Naturgas-Pipeline) system is a major European north-to-south transmission axis linking the Netherlands, Belgium, Germany, Switzerland and Italy for cross-border gas transit.
The TENP system includes four compressor stations to maintain the pipeline pressure and enable the required throughput of natural gas. From north to south they are: Stolberg (North Rhine-Westphalia), Mittelbrunn (Rhineland-Palatinate), Schwarzach (Baden-Württemberg) and Hügelheim (Baden-Württemberg).
The Hügelheim compressor station will play a key role for two-directional gas flow, particularly for the volumes entering Germany from Switzerland, because it is the closest station to the Swiss border for increasing the pipeline pressure.
The project is managed by Trans Europa Naturgas Pipeline GmbH & Co. KG (TENP KG), the owner of the gas transmission system. The TENP KG shareholders are Open Grid Europe GmbH (51 %) and Fluxys TENP GmbH (49 %).
* for the European energy infrastructure (TEN-E Regulation). EU Regulation 347/2013 defines the planning requirements for Projects of Common Interest (PCI). The Regulation aims to fill existing gaps in the European energy network infrastructure through a common effort and ensure that the necessary projects can be implemented based on a planning concept that conforms to European law (BNetzA 2016). According to the publicly available list issued by the Federal Network Agency
Since 2012, a modernisation programme has been underway to upgrade many of the of the prime movers at the compressor stations along the TENP pipeline system. At Stolberg, Mittelbrunn, Schwarzach and Hügelheim a total of nine gas turbines are being replaced by new “Frame 3” units complete with all ancillary systems. The last upgraded compressor unit is scheduled to be restarted in December 2016.
The upgrade is aimed at significantly reducing exhaust gas emissions and complying with the emission limits specified by clean air legislation (13th BImSchV). The new gas turbines have a so-called Dry Low NOx (DLN) combustion system which allows nitrogen oxide to be reduced by as much as 90 per cent.
The biggest challenge of this major asset project has been to fully maintain gas transmission along the TENP pipeline system throughout the five years of work. This was achieved thanks to a specially devised “roll-over” concept, which has allowed three compressor units (i.e. one unit per station) to be modified every year without interrupting station operation. A total of nine gas engines have been replaced or modified.
However, this resource-saving approach has also required much more upfront planning.
Apart from the prime mover replacements, the units’ ancillary systems have also been either rebuilt or replaced. The main focus here was on incorporating additional heat exchangers (recuperators) for the exhaust gas system. A total of seven of these recuperators were installed. They will increase process efficiency by using the turbine’s exhaust gases to preheat the combustion air. Recuperators require large surfaces to ensure proper heat transfer between the exhaust gas and the combustion air, which is why they are equipped with tube bundles. The large heat exchangers weigh approximately 90 tonnes.
The Trans Europa Naturgas Pipeline (TENP) ships Norwegian natural gas from the Dutch-German border over a distance of some 500 km to Switzerland and Italy. The pipeline was built in the early 1970s. Today it is the most important North-South route of the integrated European natural gas transmission system. The operator of the pipeline is Trans Europa Naturgas Pipeline GmbH & Co. KG , a joint subsidiary of the two transmission system operators Open Grid Europe GmbH and Fluxys TENP GmbH.
Open Grid Europe has been commissioned by MEGAL (Mittel-Europäische Gasleitungsgesellschaft mbH & Co. KG) to build a new natural gas compressor station in Rothenstadt (Weiden i. d. OPf.). The new station, which will have a total installed capacity of 45 MW, will be located right next to the company’s existing compressor station.
The purpose of the new station is to increase the compressor capacity in line with the anticipated increase in gas transportation requirements. The additional capacity will be used to provide the storage facilities in the south (Haidach/7Fields) with additional capacity and improve the capability of the gas transmission system in the north-south and south-north directions.
The need for the new compressor station as currently planned was identified as part of the Gas Network Development Plan (NDP Gas) 2014 and subsequently confirmed by the NDP 2015. Since autumn 2016, the approval processes have been completed and the notice of approval under the Federal Emission Control Act (BImSchG) has been issued.
Construction started in March 2016. The engineering activities have largely been completed. The three compressor buildings, the two utility buildings and the building housing the meter runs have already been erected. Installation of the process components such as the natural gas coolers, the station inlet filters and the piping is on track. The three new gas turbines will be delivered in April 2017. The station will be tied into the natural gas transmission system during the course of 2017. Commissioning is scheduled to be completed in 2018.
Commissioning of the station is planned for 2018.Herbstein compressor station new build project
The 2014 gas network development plan (NDP) and the subsequent NDPs currently under discussion contain a number of agreed construction measures to optimise the natural gas infrastructure in Germany and at the border crossing points.
These expansion projects are based on the capacity calculations made as part of the 2013 and 2014 NDPs. The network expansion measures set out in these plans are to boost the capacity of the natural gas transmission system from the north to the south and vice versa.
The regional planning procedure (ROV) for the natural gas transmission pipeline from Epe to Werne was completed in February 2015 with a regional impact assessment by the district government of Münster which confirmed the new pipeline’s compatibility with regional planning requirements.
The application to be submitted as part of the planning permission procedure (PFV) will now only be made for a shorter, roughly 16-kilometre route from Epe to Legden. With this change Open Grid Europe is responding to the new Gas Network Development Plan (Gas NDP 2014) which envisages a shorter route. The pipeline is intended to help prepare for the planned conversion from L-gas to H-gas.
Construction will start at the end of the planning permission procedure from mid-2017 onwards. The new pipeline is scheduled to be completed by the end of 2018. It will have a diameter of roughly 1,100 millimetres (DN 1100) and a design pressure of 100 bar. Running in parallel to the existing natural gas pipeline from Rysum to Werne for most of its route, it will be operated as a loop line. The pipeline route will start near Epe at the branch line station where the line from the Epe gas storage facility connects to the gas transmission system, running through the district of Borken to end at Open Grid Europe’s valve station in Legden. At the start and end points of the pipeline there will be pig traps that allow the pipeline to be inspected using an intelligent online inspection tool also known as ‘pig’
Areas affected by the construction of the pipeline include the town of Gronau and the Heek, Schöppingen and Legden communities.
The project is intended to allow new gas storage facilities and new gas-fired power plants to be connected to the network and help meet the capacity requirements of downstream network operators and cooperation partners in the NetConnect Germany (NCG) market area.
Under the 2012 and 2013 NDPs, Open Grid Europe will build a loop line from its Schwandorf station to the station in Arresting. The pipline will subsequently be extended to Frochheim to meet system requriements. The 62 km pipeline will have a diameter of 900 millimetres and a be designed for a pressure of 100 bar.
Following the completion of the regional planning procedure (ROV) in May 2015, the planning permission procedure (PFV) was completed in summer 2016. Initial construction activities including topsoil removal as well as explosive ordnance and archaeological investigations started in October 2016.
Commissioning of the 62 kilometre pipeline with a diameter of 1m is scheduled for December 2017.
Under the 2012 and 2013 NDPs, Open Grid Europe will build a loop line from the Open Grid Europe/bayernets station at Forchheim to the station in Finsing.
The new 74 km pipeline will have a diameter of 1,000 millimetres and be designed for a pressure of 100 bar.
The regional planning procedure (ROV) has been completed. The planning permission procedure (PFV) is well underway since Mai 2016.
Public consideration of the project is scheduled for February 2017. Planning permission is estimated for August 2017. Commissioning is scheduled for December 2018.