| Abstract |
In 2007 a geothermal project was realized for a tomato grower in Bleiswijk, The Netherlands. This project was realized in a cretaceous sandstone reservoir at a depth of approximately 1,700 m. Since then, numerous other greenhouse owners became interested in this energy source. However, the subsurface area required for the heating of a greenhouse is much larger than the areal extent of the greenhouse itself. Also, in 2008, oil and gas prices reached extremely high levels. This combination of circumstances initiated a ‘gold rush’ for the subsurface in order to claim the rights for the exploration of the geothermal heat contained within. In the greenport Westland-Oostland several requests to claim for these rights were made by individual applicants. The pattern of individual claims suggested a future suboptimal use of the subsurface. Confronted with this, the Greenport Westland-Oostland asked for the development of a masterplan according to which the subsurface could be divided in a more optimal way. First, a geological model of the region’s subsurface was created. Two sandstone layers occurring at depths of 1,500 and 2,500 m, respectively were identified as potential heat reservoir layers. Based on the geological findings, a geothermal modeling study was carried out to determine a more optimal well configuration. Results from these calculations show that the amount of heat extracted according to the masterplan (the optimal well configuration) doubles compared to the extraction of geothermal heat by individual projects. The masterplan comprises a total of 153 geothermal doublets spread over an area of roughly 170 km², realized in the two sandstone layers. Assuming an injection temperature of 40°C, at least 49% of the estimated 707,750 TJ of heat in place can be produced during the lifetime of a geothermal doublet. This corresponds to an average capacity of around 4.2 MW thermal per geothermal doublet. Moreover, with the masterplan approximately 25% of the greenhouses in the greenport Westland Oostland can be heated with geothermal energy for thirty years |