Smart approach results in much more geothermal heat in heat grid infrastructure

Published on 1 February 2019

Up to seven times more geothermal heat to heat homes, buildings and greenhouses can be made available if a ‘play-based portfolio approach’ is used during the development of geothermal heat projects. This is possible because this approach also significantly reduces the costs and risks associated with geothermal heat projects. This was shown in a study commissioned by Energie Beheer Nederland (EBN) and Gasunie and implemented by Berenschot and research agencies IF Technology and CE Delft. They concluded that the application of the play-based portfolio approach could be extremely significant for the scale-up of geothermal heat in heat grid infrastructures in the Netherlands as sustainable alternative for natural gas in the urban environment and greenhouse farming.

Heat grid infrastructure can cover 270 PJ in annual heat in over 300 municipalities

The Berenschot, IF Technology and CE Delft study examined the heat demand in urban areas and greenhouse farming (industrial heat demand has not yet been included). It was concluded that approximately 270 PJ (approx. 50%) of this heat demand can be met with a collective heat provision via a heat grid infrastructure. The report shows that it is expected that in 347 of the current municipalities in the Netherlands, collective heat supply is a way to improve sustainability. Geothermal heat can be a source for such heat grids, if the cost price of the heat is favourable and geothermal heat is possible at the site. Other sources for the delivery of heat include residual heat and heat from biomass firing.

The play-based portfolio approach

Geothermal heat can offer an important contribution to the climate objectives that the Netherlands has set for itself: 49% CO2 reduction by 2030 and (as objective of the Paris Climate Agreement) 95% reduction by 2050. Geothermal heat should be able to supply a significant part (indicative 30%) of the current heat demand, which is currently still covered mainly by natural gas. It is thus important to realise the geothermal heat potential. This, however, demands a considerable scale-up of geothermal heat solutions. A systematic and smart harmonisation is needed between the above-ground demand for heat and the heat grid infrastructure, and the below-ground supply of heat. TNO and EBN produced an initial design in 2018 of the so-called ‘play-based portfolio approach’ in which geothermal heat can be scaled up in a safe and responsible way. This approach requires planned management and goal-oriented extraction of geothermal heat as the basis for sustainable and coordinated development of geothermal heat projects. Partnerships and knowledge-sharing are important aspects in this: follow-up projects can make optimum use of the knowledge and experience gained through deep subsurface drilling. This reduces the risks and costs.

Smart approach significantly increases development of geothermal heat

The subsurface contains a tremendous amount of heat. The development of this is still in the exploratory phase in a large proportion of the Netherlands. In some areas, a lot is known about the potential and relatively little is known in others. The play-based portfolio approach was further investigated by using this on a limited part of the heat demand and geothermal supply. The subsurface comprises plays and sub-plays, formations with comparable geological features, in which, based on the repeat potential, risks and costs can be significantly reduced through learning effects. The application shows that the play-based portfolio approach already comprises some three plays, about which rather a lot is known, 62 PJ of the 270 PJ in annual collective heat demand can be connected to geothermal heat. The total potential for geothermal heat in the Netherlands is not yet known. If geothermal heat projects are developed stand-alone in these same three plays, it is estimated that only around 8 PJ can be connected to geothermal heat. The economic potential of geothermal heat thus increases by a factor 7. Using the play-based portfolio approach provides more information about the below-ground potential in a socially and economically responsible way and can optimise the link with the above-ground potential.