Subsurface in the energy transition

Published: 23 March 2018

One of the technologies designed to cut carbon emissions in the Netherlands is subsurface energy. In the transition to sustainable systems, this resource will be crucial for heating and cooling buildings without using natural gas. As systems like this spread below ground, the subsurface is getting 'crowded' and so we will have to use the space below our feet as efficiently as possible. At Deltares we are working hard on research and innovations that contribute to the energy transition. That is why we are proud that Deltares consortia have won three new projects for further research looking at subsoil energy.

CRYSTAL clear energy storage

In the years to come, the number of Aquifer Thermal Energy Storage (ATES) systems in cities will increase sharply. In very built-up areas, these systems can affect each other. There is still little coordination of ATES systems and the adopted remedy has been to maintain large distances between them. ATES managers are concerned that neighbouring ATES installations will have a negative effect on their own systems and so no permits are being granted for extra storage.

The CRYSTAL research project provides a picture above the ground of how energy storage is developing below the surface. Previous research has already shown that glass fibre can be used to monitor and improve subsurface energy systems. This new study continues the development of the monitoring system and is also developing software (a dashboard) that makes data from the monitoring system clear to read. The dashboard can be linked to building management systems in order to optimise ATES. The information can be used by municipal and provincial authorities, as well as private bodies, to implement coordination and make new agreements. Ultimately, these are the bodies who determine the extent to which agreements are made to collaborate at the area level.

 

Subsurface systems in closer proximity

How is it possible to install more subsurface energy systems closer together in a context of permits and differing interests? And what regulations are needed for areas where ‘crowding’ is not yet an issue?

To answer these questions, Deltares is collaborating with the Utrecht City and Provincial Authorities, BodemenergieNL, If Technology and KWR Water Research. The research is focusing on subsurface energy systems down to a depth of about 250 metres. The primary focus is on the effect of system density on energy and cost savings, and on the impact of an increase in the number of systems on total energy savings. The study is also looking at the extent to which merging individual systems allows the subsurface to be used better.

The results are being tested in a case study in the centre of Utrecht and they will ultimately provide a framework with assessment criteria for subsurface energy systems in busy areas. This framework can be used directly by civil servants, permit authorities and designers everywhere in the Netherlands where there are large numbers of subsurface energy systems.

Smart buildings

Systems that use subsurface energy to regulate the climate in buildings must function optimally. A range of systems are on the market (such as SIMAXX) that continuously check data from building management systems and therefore monitor energy consumption. What is lacking in the current systems is a real-time comparison between measured performance and expected performance. Managers lack a complete picture.

Deltares is involved in work on new models to enable the real-time comparison of design models and measurements. This new monitoring system will result in managers being informed at an early stage about sub-optimal performance and provide them with a picture of possible thermal imbalances. They will therefore have a better tool available to ensure that subsurface energy systems function optimally. Moreover, this advanced monitoring approach will provide a sound basis for smart control systems.

These three new projects provide fundamental new knowledge and take us a step further on the road to the much-needed energy transition in the Netherlands. The projects have received subsidies from the top sector policy TKI Urban Energy and KIBO.

Read more on the opportunities for renewable energy from water and subsoil.