Test drilling has been carried out on the campus in preparation for the construction of an underground thermal storage system: High Temperature Open Ground Energy (HTO) system. The HTO system is one of TU Delft’s initiatives as it heads towards a CO₂-neutral, circular and climate-adaptive campus by 2030. This system enables the storage of excess heat production from the geothermal installation in the summer, which can then be used during periods of increased demand in the colder months. By doing this, we make the most efficient use of the geothermal heat source. The test drilling mapped the soil conditions to a depth of approximately 200 metres. The results will allow us to determine the best storage depth for the hot water. From this, it has been determined that there are usable, water-permeable sand layers suitable for an HTO system.

Scientific research

The on-campus HTO system is part of PUSH-IT and Warming-up-GOO, a European and a national research programme into underground heat storage, respectively.

Facts and figures

• Depth: approx. 200 meter
• Storage volume: approx. 500.000 m³
• Temperature lukewarm spring: 40-55°C
• Temperatuur hot spring: 75-80°C
• Amout of heat: approx. 40 TeraJoule

Water Act permit

A permit under the Water Act is required from the provincial authority as permission for the construction of the HTO system. The provincial authority assesses the effects of such a system against various environmental aspects to ensure that the surrounding area will not be unduly affected. On the basis of the assessment, the Provincial Executive of the Province of South Holland granted the required permission on 3 December 2024. The documents accompanying this decision will be available for inspection for six weeks at the offices of the Haaglanden Environment Service. This means there is an opportunity for people to submit an opinion up to six weeks from the date of publication. Once the HTO system has been constructed, the Haaglanden Environment Service will monitor to ensure that the system is used within the set frameworks.

Schedule

• Test drilling: March – May 2024

Subject to final decision on system construction:

• Start design process of the entire system: Q1-2025
  Innovations from the PUSH-IT research will be incorporated into this process.
• Implementation of the monitoring system: Q2 2025
• Start connecting pipework construction: Q3 2025
• Start well construction: after Q3 2025
• The construction of the HTO plant is an integral part of the heat pump plant at the geothermal site and will align with this schedule. Work on the heat pump plant is set to begin in Q3 2025.
• Commissioning of the HTO system: End of 2026

More information

For more information about the work, please contact secr-crefm@tudelft.nl

More details about the research programmes and what is specifically being researched at the TU Delft Campus can be found at . www.push-it-thermalstorage.eu/ and https://www.warmingup.info/.

Want to read more about Martin Bloemendal’s research? Read his ‘Story of Science‘ about underground heat storage on campus.