| Title | A Techno-Economic Evaluation of High Temperature Thermal Aquifer Storage (HT-ATES) for Use with the Geothermal Well on the TU Delft Campus |
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| Authors | Martin BLOEMENDAL, Philip J. VARDON, Marc PIJNENBORG, Gustas SUDINTAS, Anne MEDEMA, Kijze MARIF, Stijn BEERNINK, Franklin Van VELDHUIZEN, Sander SNELLEMAN, Tebbe VAN OORT |
| Year | 2020 |
| Conference | World Geothermal Congress |
| Keywords | storage, ATES, high-temperature, techno-economic |
| Abstract | Direct use geothermal projects are often considered to be able to supply a base-load heating, which leaves a substantial portion of the heating demand to be covered by other (often fossil-based) sources during demand peaks. Additionally, during a substantial portion of the year there is less heat used from the geothermal well than is able to be produced. The consequence is that geothermal projects perform economically poorly or require substantial governmental subsidies. The use of heat storage provides a possibility to address both of these issues by providing seasonal storage of heat, thus increasing the peak supply and utilising more heat from the geothermal well. Given the required storage capacity needed for such projects, Aquifer Thermal Energy Storage (ATES) is the only realistic storage option. This paper presents a techno-economic analysis of using a High Temperature (HT)-ATES system in conjunction with a 2.2km deep direct use geothermal project for the TU Delft campus. The geothermal project has been designed as a living lab, a research and operational project, and adding an HT-ATES system would add to this dual purpose. The heat supply and demand, the available aquifers, initial project design, economics and greenhouse gas emissions are investigated. Two possible aquifers are identified for use, the first 50m thick at ~130m depth and the second about 50m thick at ~410m depth. The first is evaluated as more favourable economically, whereas the second reduces the potential for impact on other groundwater users. The amount of sustainable heat delivered for use on the TU Delft campus is calculated to increases from ~65% with only a geothermal well to ~95% when also a HT-ATES is used, with the same proportion of greenhouse emission savings. Several scenarios for heat delivery are considered, as the increased supply also allows a portion of the city around the university to be supplied with heat from the geothermal project and HT-ATES. The calculated net present value of the total project (i.e. the geothermal project and the HT-ATES project) improved by between €3m to €9m. |