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Dutch Groningen Output Must be Halved: Regulator
Groningen gas output must be cut back significantly and immediately for safety reasons and possibly stopped altogether later on, the Dutch mining supervisory body SSM has advised the ministry for the economy.
There was an earthquake in early January, after which the operating company NAM, a Shell-ExxonMobil joint venture, said that a reduction in output would be sensible.
In a statement February 1, the SSM said: "A major intervention is necessary in order to probably meet the safety standard and to reduce the risk of damage. Despite our inability to predict accurately which earthquakes will occur at which level of production, we advise the minister to reduce the gas production as soon as possible to a maximum production level of 12bn m³/yr. The uncertainties in this assessment are large. We therefore choose to be on the conservative side. After all, it concerns the safety of the inhabitants of Groningen."
Current Groningen output is capped at 21.6bn m³/yr, down from a little over 50bn m³/yr earlier this decade.
The regulator advised the immediate and complete closure of the Loppersum clusters, preventing them from being deployed at high capacity during a significantly cold period. "Running the Loppersum clusters at full capacity could significantly increase the probability of more and possibly heavier earthquakes. There is a possibility that the opening and shut in of these clusters initiated the Zeerijp earthquake on the 8th January 2018. Ceasing production is also expected to have a positive effect on the seismicity in the short term (3-6 months)," it said.
The best assessment SSM said it could make is that, at a production level of 12bn standard m³/yr, the calculated risks in the period 2018 to 2022 will – with reasonable certainty – meet the personal safety norm. SSM understands that this number suggests that it is possible to accurately determine at which production level the safety norm is met. However, this is not the case.
SSM has applied a uncertainty margin when advising the recommended production level to deal with the major uncertainties. As a result of the applied margin, the safety norm is expected to be met with an estimated probability of 90%. With these production measures SSM expects to return to ‘code green’. This means that the likelihood of earthquakes – and also the heavier ones – is expected to decrease strongly, with damage being prevented and limited as much as reasonably possible.
Another step would be to "immediately limit the fluctuations in production from the Bierum cluster to a maximum of +/- 20%," it said.
The Bierum cluster is situated near the Loppersum clusters. This cluster can continue to produce, however fluctuations must be limited immediately to +/- 20% due to the fact that these have an effect in the Loppersum area and might initiate earthquakes.
The third measure is to limit the regional fluctuations in the production of the other clusters as soon as possible to the current level of +/- 50%. If the proposed measures are implemented, the limitation of fluctuations for production for the entire Groningen gasfield can be abandoned, it said.
SSM said that the feelings of insecurity and the social consequences of gas extraction were rising. In addition, with continued pressure drop as a result of production, seismicity will increase again raising the risk posed by earthquakes: "I therefore expect that the gas production will need to be reduced further in the future, if necessary to zero,” said the inspector-general, Theodor Kockelkoren.
The reduction of gas production may have consequences for the security of supply of gas to companies and households, but SSM said that it was not its role, as the supervisor of the safe extraction of gas, to take these factors into account. Gasunie Transport Services (GTS) advises the minister on security of supply, it said, and the minister will make an assessment of the safety risk and the gas production level necessary for security of supply. The minister ultimately determines which measures must be taken by NAM.