Bevindingen van het NWO-onderzoeksprogramma Schaliegas & Water: de relatie tussen bodemexploitatie en waterkwaliteit

Workshop on Sustainable Use of the Deep Subsurface

Despite the many decades of oil and gas activities in the Netherlands, relatively little social and scientific attention was paid at first to their impact on the environment and society. But over the last few years societal interest in the impact of deep subsurface activities has grown strongly, triggered principally by the land subsidence resulting from gas extraction and by the possible start of shale gas extraction projects.

The potential consequences of subsurface activities on groundwater availability and quality is seen as an important concern in this regard. To gain an understanding of this impact, the NWO program Shale gas and Water was initiated in 2015 as a joint research program between three water companies (Oasen, WML and Brabant Water), KWR and a consortia of universities (Utrecht University, University of Amsterdam, and Wageningen University & Research).

The research program was concluded with a workshop on November 21 at KWR where the results from the past four years we shared, and also what these results can teach us about a future sustainable use of the deep subsurface.

The NWO program Shale gas and Water – what did it deliver?

The four-year Shale Gas and Water program was focused on researching the environmental risks shale gas production could pose to the water system in the Netherlands, the possibilities of avoiding these risks, and the functioning of national and international legal frameworks.

Gilian Schout (UU) presented his research on lessons learned from monitoring of old, abandoned wells in the Netherlands and the risks for methane leakage. Gilian found that methane can leak from deeper layers in groundwater – though advanced and accurate measurement techniques are needed to properly detect these leaks.

Ann-Hélène Faber (UU/UvA) investigated the composition, and associated risks of shale gas waste waters. Of the almost 1400 components used in shale gas fracking in the US, only 44% were found to be regulated within the EU. Prioritisation of these chemicals is necessary to focus efforts on the regulation and replacement of most toxic chemicals with green alternatives.

Andrii Butskovkyi (WUR) calculated the water demand for shale gas production and assessed the suitability, in terms of quantity and quality, of water sources in the Netherlands. Andrii also investigated different treatment options for flowback and produced waters. Tessa van den Brand (KWR) presented the results of a lifecycle analysis (LCA) for the different treatment options for produced waste waters. The LCA results were limited by a lack of available data on chemicals, highlighting the need for better information to adequately define the impacts of shale gas and other oil and gas related activities.

Herman Kasper Gilissen (UU) discussed the role of government and law to regulate the environmental risks associated with subsurface activities. A central theme of Herman’s presentation was the difficulty in regulating an industry which is still rapidly evolving, where chemicals change frequently and where so much is still uncertain. Finally, the morning session was wrapped up by Annemarie van Wezel (UvA) who gave an overview of the research program’s output to date.

Sustainable use of the (deep) subsurface: what does the future have to offer, what do we need?

Ruud van Nieuwenhuijze (Brabant Water) gave an overview of the vision from the supporting drinking water utilities. The take home message from Ruud was that the research program substantiated the concerns of the drinking water utilities in the Netherlands. Though shale gas is not going forward in the Netherlands, the results of the research will be relevant, especially in light of the energy transition and the increased use of the subsurface. The knowledge and network between the water and energy sector will remain valuable beyond the end of the research program.

Niels Hartog (KWR) presented an outlook on the future for the sustainable use of the (deep) subsurface. The Netherlands has both a long history of use of the deep subsurface (e.g. conventional oil and gas exploration) and is rich in freshwater resources. The challenge, therefore, is to protect those resources while still benefiting from the subsurface in a sustainable way. In the context of the energy transition, the deep subsurface will be increasingly used for storage (e.g. thermal, CO2, hydrogen, natural gas etc) and new applications for the subsurface will need to be optimized hand in hand with investigations into the possible impacts. More research is needed to minimise the risks on the forefront and better, smarter monitoring to detect problems early.

The workshop closed with a panel discussion on the future research agenda for the deep subsurface. The panel was a multidisciplinary group, with representatives from the energy sector (Jorien Schaaf, EBN), the Dutch science funding agency NWO (Hayfaa Abdul Aziz), the water and environmental sector (Annemarie van Wezel, UvA) and governance and regulation (Marleen van Rijswick, UU).