"No, a similar calamity cannot happen again," Marco van Soerland, managing director of geothermal energy company Trias Westland, said in an update yesterday in response to an incident resulting in a prolonged failure last autumn.
Not long afterwards, it emerged that a FOI request (Freedom of Information) had been submitted to bring research reports to light. The reports, sent by Trias to the State Supervision of Mines (SodM), have largely been made public.
Reputational damage
As usual with Wob requests, certain passages have been blacked out. However, it is striking that much of the information remains legible. Lessons must be learned from this information, says SodM. For example, about the spatial planning of (future) geothermal sources.
The FOI request was received on 2 December. The documents and a letter of explanation from SodM reveal that Trias Westland feared damage to its reputation if, in the event of disclosure, information 'would not be placed in the correct perspective'. However, SodM has ruled that general lessons can be learned from the incident. For example, it decided to make public, without going into specific details, a passage about 'the lack of certain elements in certain procedures'.
What happened at Trias Westland?
After Trias Westland had carried out maintenance work on 10 September on one of the two production pipelines, the geothermal heat installation was restarted. SodM writes that during this start-up process 'gas under high pressure from the degassing installation entered the production pipeline in an uncontrolled way. This gas then forced a quantity of water through the pipeline with brute force, causing it to collapse'.
The investigation report refers to a 'cold start-up' of the installation that is 'not a routine activity'. The geothermal installation at Trias has a 'start-up programme for the automatic start-up of production that is 'fully' automated.' The SodM speaks of 'operator error' in the report. "It was decided to have the start-up of production take place automatically, without consulting the necessary control description, and without realising that the start-up could take place without balancing the pressure difference."
The effect of the pipe collapsing was successively 'flying debris, outflow of the gas from the degassing installation, damage to a supply cable and thus the creation of a spark which led to ignition of the gas cloud in the form of a high flame jet'.
Learning lessons
An incident like this is classified by SodM as one involving a risk of serious or even fatal injury. Pieter van den Bergen, Director of Geothermal Energy at SodM, said in a press release when the documents were published: "We are currently seeing that plans are being made throughout the Netherlands for geothermal energy in the built environment. We can and must learn from all the knowledge and experience that has been gained in recent years, particularly in the horticultural areas. So also from this incident in Naaldwijk. SodM believes it is important that this sharing of knowledge takes place in order to prevent incidents like this in the future."
Despite the high risk profile of the incident, only material damage was caused to the Trias Westland installation. According to SodM, this was due to Trias Westland's safety measures not to have persons at the site during start-up and to the spacious layout of the site, as a result of which the effects remained within the boundaries of the site.
Lessons learned
According to SodM, the Trias Westland investigation, the safety studies that followed and reviews of investigations have taught the geothermal industry and other stakeholders various technical and organisational lessons that may be of value to existing and new geothermal sites. For example, they point to the 'optimisation of procedures for routine and non-routine work' and 'adjustment of the regulations to ensure that large pressure differences are settled in a controlled way before any follow-up action is taken'.
Both SodM and Trias Westland have a role to play in sharing the lessons learned, SodM believes. The authority therefore expects Trias Westland, as stated in a press release, to play an active role in this.
More time to think at the front end
Director Marco van Soerland has already let it be known that, although the incident 'should not have happened', he is proud of 'how we handled it, intervened and took measures afterwards'. "As a result, we have accelerated important steps in the development of geothermal energy in our organisation. Especially at the front end of new developments, we take more time to consider potential risks in the design. So things have definitely happened in terms of safety and risk awareness, both in terms of technology and procedures."
Back in production
At the end of December 2021, SodM concluded that Trias Westland had taken all the necessary technical and organisational measures to prevent such an incident in the future and to start up the current installation in a safe and responsible manner with the current project organisation. This put an end to an unfortunate incident for more than fifty connected growers, who at the time were facing very high gas prices due to the loss of geothermal energy supply.
In the near future, SodM will share the lessons learned in various ways with the various target groups such as active operators, future operators, local competent authorities and citizens. In addition, in its future supervision SodM will pay attention to the way in which initiators or operators have incorporated the lessons into their projects.
The investigation report, Trias' plan of action for the follow-up of the incident and the decision letter containing the reasons given by SodM can all be found on the SodM website.