Nearly half of the Dutch energy demand consists of the heating of homes, businesses, industry and horticulture. Currently, this heat is almost entirely produced by burning natural gas in factories, power plants, homes, offices and greenhouses. But, the burning of natural gas has important disadvantages. The Netherlands is becoming increasingly dependent on the import of natural gas. With the current rate at which we extract natural gas in Groningen, the Netherlands will have depleted its natural supply within decades. In addition, the emission of the combustion gasses contributes to global warming. Reduction of the use of natural gas is therefore an urgent aspect of the policy goal towards a sustainable energy supply. But how?
Even though the heat demand is huge, there are some regions, such as South Holland, where there also is a large amount of waste heat available in the petrochemical industry, power plants and waste treatment plants. Part of it is already being exploited by heating networks in the built environment. However, there is debate about the sustainable nature of this ‘coal heat' and the availability of it in the future is uncertain.
Should we therefore abandon the construction of these heat networks? On the contrary. Indeed, there is a different and much more sustainable and cost efficient heat source which can be utilized using the same infrastructure, namely geothermal energy. With geothermal power plants, hot water between 80 and 120 degrees Celsius is pumped up from 2 to 4 kilometers deep.
With the current information on the subsoil and the first deep drillings realized, geothermal energy seems to be able to fulfill in the heat demand of a large part of the Netherlands. In addition, compared to small-scale measures such as solar heat and heat pumps, geothermal energy is by far the most cost efficient form of heat extraction (euro/PJa). Geothermal energy has another important advantage: the visible spatial impact is minimal. This means that the social resistance will be expected to be at a minimum and large scale implementation will be realistic.
In the coming years there will be regions in the Netherlands where demand and supply of waste heat and geothermal energy are close together. Here the first ‘regional smart thermal grids’ will arise. In the coming decades, waste heat and geothermal energy will be transport along a larger distance through well-insulated piping so that other regions will be connected on the grid. Slowly but surely a nationwide, robust heat network will emerge with a large variety of heat suppliers and demander: the 'Dutch Smart Thermal Grid.