Direct heat resource assessment and subsurface information systems for geothermal aquifers; the Dutch perspective

Abstract

A resource assessment methodology has been developed to designate prospective high permeable clastic aquifers and to assess the amount of potential geothermal energy in the Netherlands. It builds from the wealth of deep subsurface data from oil and gas exploration and production which is publicly and digitally available. In the resource assessment various performance indicator maps have been produced for direct heat applications (greenhouse and spatial heating). These maps are based on detailed mapping of depth, thickness, porosity, permeability, temperature and transmissivity (methodology presented in other papers in this NJG issue). In the resource assessment analysis 14 lithostratigraphic units (clastic aquifers) have been considered, ranging in age from the Permian to the Cenozoic. Performance maps have been made which include a) the expected doublet power (MWth) to be retrieved; b) the number of houses or hectares that can be heated from one doublet; and c) a potential indicator map, which provides insight in subsurface suitability for specific applications from a techno-economic perspective. To obtain a nationwide overview of the resource potential in terms of recoverable geothermal energy, a progressive filtering approach was used from total heat content of the reservoirs (Heat In Place – HIP) via the heat that can potentially be recovered (Potential Recovery Heat – PRH) to energy maps taking into account a techno-economic performance evaluation (Recoverable Heat – RH). Results show that the HIP is approximately 820,000 PJ which is significantly more than previous estimates of around 90,000 PJ. This considerable increase in geothermal energy potential is the result of accurate geological mapping of key reservoir properties and the development of state-of-the-art techno-economic performance assessment tools that performs Monte Carlo simulation. Moreover, for the previous estimates boundary conditions were set with the aim to compare the geothermal potential between different EU countries (Rijkers & Van Doorn, 1997). Taking into account techno-economic aspects, the RH is in the order of 85,000 PJ. This is equivalent to ~70% of the ultimate recoverable gas of the Slochteren Gas field. In total over 400 maps have been created or used as input for the resource assessment. Together, they provide comprehensive information for geothermal energy development from various stakeholder perspectives. The maps can be interactively assessed in the web-based portal ThermoGIS (www.thermogis.nl). This application complements existing subsurface information systems available in the Netherlands and supports the geothermal community in assessing the feasibility of a geothermal system on a regional scale.

Geology of the Upper Jurassic to Lower Cretaceous geothermal aquifers in the West Netherlands Basin – an overview

“…Therefore, uncertainty remains as to the net aquifer thickness, which is a key element of sedimentary aquifer architecture. This affects the prediction of lifetime and interference (Mijnlieff & Van Wees, 2009;Hamm & Lopez, 2012;Crooijmans et al, 2016), and heat-in-place estimates (Vis et al, 2010;Kramers et al, 2012). Intervals with higher flow rates can also be more subject to erosion, scaling and corrosion, and therefore the simple completions also restrict well-integrity studies.…”

Exploration for deep geothermal reservoirs in Luxembourg and the surroundings - perspectives of geothermal energy use

“…From an economic and ecological point of view, the heat remaining after power production should be used according to the principle of cogeneration or combined heat and power generation (International Energy Agency 2011; Paschen et al 2003). The technical lifetime of a doublet system usually is 30 years (e.g., Kramers et al 2012), which is due to the fact that conductive heat flow within rock is too small to compensate heat extraction (Muffler and Cataldi 1978).…”

Introduction to the geothermal play and reservoir geology of the Netherlands

“…The Dutch geothermal plays comprise a large heat source holding 821,000 PJ, the geothermal source (Kramers et al, 2012). The size of the geothermal resource is more difficult to ascertain because project economics are included in the definition of geothermal resources (UNECE, 2016).…”