WarmtelinQ milestone: Vlaardingen - The Hague heat transfer pipeline set to be filled after four years of construction

Work on the construction of the underground pipelines between Vlaardingen and The Hague has been ongoing since 2022. Now that this section is complete, a roughly two-month test period can start. This will involve filling and testing both the supply and return pipelines.

Gasunie’s Heat Transport Director Inge Aardse explains: 'This water filling phase marks a key step towards commissioning the heat transport system. We started construction on the pipelines four years ago, and we’ve now reached the point where we can fill them for the first time. This brings us another major step closer to completing our work. Excellent collaboration with the contractors, the Province of Zuid-Holland, the municipalities involved and the local communities has helped us to achieve this result.'

Around 16 million litres of specially treated water will be used to fill the pipeline, which equates to roughly 6.5 Olympic swimming pools. The water used has been degassed and demineralised. It contains virtually no oxygen, which prevents rust and corrosion in the pipelines. The pipeline will be gradually filled from Vlaardingen towards The Hague, and this period will last around five weeks in total. The pipeline will be filled 24 hours a day.

The coming weeks will focus on testing the system so that further steps towards commissioning can subsequently be taken. If all goes to plan, heat can be supplied for the first time on the Vlaardingen - The Hague section in spring 2027. In the meantime, the team is working hard on the construction of the pipelines between Rijswijk and Leiden.