Nitrogen+Syngas 375 Jan-Feb 2022
31 January 2022
Closing down the Groningen gas field
GAS MARKETS
Closing down the Groningen gas field
Gordon Feller looks at Gasunie’s plans to build a new nitrogen plant at Zuidbroek to allow for the progressive shutdown of the Groningen gas field, one of the largest in Europe.
What’s next for gas in Europe? One answer to this question comes from the world’s largest provider of finance for economic development; the Luxembourg-based European Investment Bank, owned by the member states of the European Union. The EIB is lending a large sum to Dutch gas companie Gasunie to finance the construction of a nitrogen facility in Zuidbroek, near Groningen.
From their global headquarters in the Dutch city of Groningen, NV Nederlandse Gasunie invests in and operates natural gas infrastructure and transportation systems and storage facilities. They are especially active in the Netherlands and Germany. Gasunie owns the Netherlands gas transmission network, which has a total length of over 12,000 kilometres. It also owns a 3,100 kilometres long network in Germany. The relationship between Gasunie and the EIB goes back a long way; the second project the European Investment Bank financed in the Netherlands was with Gasunie in 1969. This is the 7th collaboration between the EIB and Gasunie since then.
Nitrogen plant
The investment in question entails the construction of a nitrogen plant in Zuidbroek, the Netherlands. The EIB will provide financing of e240 million out of the project’s total cost of e502 million.
The project is focused on constructing a 180,000 m3 /hr nitrogen production plant and its associated facilities (gas and electricity connections as well as gas blending stations). Excess nitrogen will be sent to an existing salt cavern when needed, which was converted into an underground nitrogen storage at the time of the construction of a nearby nitrogen plant (at the existing Zuidbroek 1 capacity is 16,000 m3 /hr nitrogen) operated by Gasunie Transport Services BV since 2012.
The air separation plant will produce high purity nitrogen gas, which will be compressed and then blended with imported high calorific value gas (H-gas). The mixed gas, a ‘pseudo-Groningen’ gas, will then be injected as low calorific value gas (L-gas) into the Dutch gas network, thus replicating the gas technical specifications used in the Netherlands and surrounding regions/ countries and allowing for the reduction of supplies from the Groningen gas field. The project’s main components are several key elements of the facility: air separation units to extract the nitrogen; compressing and cooling units; and mixing stations.
As with all such projects, an extensive and in-depth Environmental Impact Assessment was required by the EIB, in order for the project funds to be approved. The primary environment impacts during construction concern the disturbance to communities, in particular the expected increase in traffic volume, as construction will take place concomitantly with the installation of a solar park and wind farms nearby. The technology which is being used for the air separation units is considered by Gasunie to be “the best technology available to produce nitrogen at high degree of purity level and in large quantities”. It is a cryogenic nitrogen production plant. This type of installation operates at very low temperatures and requires a large amount of energy/electricity.
Groningen
Adding nitrogen to imported gas is needed for its use inside Gasunie’s Dutch network. It will allow Gasunie to progressively close down the Groningen gas fields. In view of earthquakes caused by the extraction of natural gas from the Groningen gas field, the Dutch Ministry of Economic Affairs and Climate Policy mandated that Groningen gas production is to reduce as quickly as possible to achieve a complete shut-down of the field in 2030. However, because gas from the Groningen field is of a lower calorific content than other gas supplies, their high calorific content risks damaging the network and would entail the replacement of all end-users’ appliances. Hence the addition of the new nitrogen plant, which will provide nitrogen to be compressed and blended with imported gas before it goes into the Dutch gas network.
The project is categorized as one of “strategic importance” to the Netherlands, since it supports the official request from the Ministry of Economic Affairs and Climate Policy (EZK) to urgently decrease Groningen gas production to 12 bcm by 2020 and thereafter to proceed to a complete shutdown of this field by 2030, in order to reduce the induced-seismicity risk in the region. According to national legislation, the project (new nitrogen plant, gas blending station and, among other things, the associated construction of approximately 4 km of natural gas transmission pipelines) falls under the National Coordination Scheme (RCR). This means among other things, that the project must fit within a Spatial Integration Plan (RIP) that is determined jointly by the Ministry of Economic Affairs and Climate and the Ministry of the Interior and Kingdom Relations. This procedure also includes the decisions required for the project (permits, approvals etc.) and is coordinated by the Ministry of Economic Affairs and Climate.
Site selection
The precise location of this project was chosen based on a study which considers the environment as one of the main criteria. Out of five locations studied, the most appropriate is Tussenklappen, in Zuidbroek, considering spatial integration and distance to existing facilities. A separate procedure has also been launched by Gasunie to apply for a modification of the nitrogen storage plan regarding the change in the utilisation of the existing salt cavern at Heiligerlee. This is already used as a buffer nitrogen storage to the existing nitrogen plant in Zuidbroek. The underground nitrogen storage is not part of this project’s scope. However, taking a risk-based approach, the EIB did review and assess the environmental and safety elements of this facility
“the Dutch Ministry of Economic Affairs and Climate Policy mandated that Groningen gas production is to reduce as quickly as possible.”
The project is being implemented within agricultural lands, in a location where natural gas installations and nitrogen production infrastructure are already in place. As such, existing infrastructure will be used wherever possible. The gas and electricity connections will be buried. Emissions from the production process mainly consist of oxygen with a few impurities and are in line with emissions standards defined in Dutch national legislation. Cryogenic processes typically occupy large ground surfaces. The nitrogen plant is being designed such as to minimise landscape impacts through a specific landscape integration plan. The project is located in an industrial gas estate, at some distance from residential areas. For this reason Gasunie says that the impacts on population and human health are considered to be “low”.
Given the low temperatures and the high volumes involved, cryogenic nitrogen production processes are energy-intensive; the selection procedure was partly based on Total Cost of Ownership (energy consumption, operations and maintenance), with emphasis placed on overall energy consumption levels, such as using more efficient electromotors, installing centrifugal compressors and integrating heat exchangers in the ASU. The plant will be electrically-driven with green electricity supplied by TenneT from solar and wind sources, supplemented by a back-up power generation (diesel) that can operate continuously for a period of three days and would potentially run on an occasional basis. The national electricity grid factor has been used to account for the energy supply emissions.
Given its proximity to the Groningen area, the project is designed to be seismic-proof, in line with the Eurocode 8 Directive and national legislation. The project is also located on a low-lying polder which potentially constitutes a flood-prone environment. The flooding risk is exacerbated by climate change in the area, such as rising sea levels, wetter winters and drier summers. This has been taken into consideration in the Draft Spatial Integration Plan. The flooding risk and associated safety standards are controlled regionally by the Groningen Province in consultation with the agencies that set the safety policy objectives on these matters. An adjacent dyke is planned to be completed in 2021, which will reduce the flooding probability in the project area to 1:1,000 years from the present 1:300 years. The project’s infrastructure will also be raised on higher grounds to further mitigate flooding risk on its components. Additional flood-proofing elements might be incorporated into the project’s design, which are to be captured in the “Final Spatial Integration Plan”.
Public consultation
Public consultations, with a serious effort at stakeholder engagement, have been a high priority for the EIB’s own team – and for Gasunie. They consulted with regional authorities (municipality, province, water, conservancy, etc.) for a period of months at the outset of the project development. Relevant opinions and comments were incorporated into the RIP. A public hearing near Heiligerlee also took place. Most of the comments raised by the public refer to the salt cavern in Heiligerlee, which is not part of the RIP but is connected with the nitrogen production plant.
The outcomes from the public consultations have been integrated in the final RIP documentation and the design of the project was slightly modified to further mitigate flooding risks and noise pollution. The comments concerning the salt cavern in Heiligerlee were addressed in the form of clarifications in the final RIP documentation and will be further incorporated as much as applicable and feasible in a separate permitting procedure submitted by the Gasunie for the modification of the nitrogen storage plan.
