Local-Scale Maps of the NSGE Potential in the Case Study Areas
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Local-scale maps of the NSGE potential in the Case Study areas Local-scale maps of the NSGE potential in the Case Study areas Deliverable D.4.2.1 – Local-scale maps of the NSGE potential in the Case Study areas 16/12/2015 – 01/06/2018: The deliverable will present the work carried out in each Case Study by the relevant project partners, and it will be the input for WPT4 to implement the Near-Surface Geothermal Energy in the energy planning procedures. Version: Revision 02, 04 September 2018 This document is the third deliverable of the Work Package 4 (or WPT3 according to the EmS numbering of WPs) “Assessment and mapping of the potential of Near-Surface Geothermal Energy (NSGE)”. Politecnico di Torino (POLITO), as responsible partner in the WP4, elaborated this report with the contribution from the involved project partners: TUM, EURAC, ARPA Valle d’Aosta, GeoZS, BRGM, GBA, University of Basel. This deliverable focuses on the local-scale mapping of the NSGE closed-loop potential (Borehole Heat Exchangers, BHEs) and open-loop potential (Groundwater Heat Pumps, GWHPs) in 6 case-study areas. Among the various existing mapping methods, the G.POT method developed by POLITO was chosen for closed-loop potential while, for open-loop, a method was developed by TUM in collaboration with POLITO and ARPA VdA. The common outputs are closed- and open-loop maps of geothermal potential expressed in MWh/y. Regarding the open-loop potential, maps of technical volume flow potential (l/s) and power (kW) were also realised. All maps in this document are available and downloadable as raster files (tiff), contained in zipped folders, at: https://areeweb.polito.it/ricerca/groundwater/zip/GRETA_NSGE_potential/. This report serves as a reference guide for the methodology applied, as well as for a better understanding of the outputs of NSGE potential assessment. It is meant to help installers, designers, and public authorities involved in the design, approval and installation of NSGE systems. GRETA is co-financed by the European Regional Development Fund through the Interreg Alpine Space programme. Send us an email at [email protected] and see more about GRETA at www.alpine-space.eu/projects/greta. Local-scale maps of the NSGE potential in the Case Study areas TABLE OF CONTENTS 1 Introduction ..................................................................................................................................... 5 1.1 Partner´s involvement ............................................................................................................. 6 1.2 Acronyms and definitions referring to NSGE .......................................................................... 6 2 Literature review on near-surface geothermal potential assessment methods ............................ 7 2.1 Tables of extractable thermal power (BHEs, SHCs) ................................................................. 7 2.1.1 VDI 4640 (BHEs) ............................................................................................................... 7 2.1.2 MIS 3005 (BHEs, SHCs) .................................................................................................. 11 2.2 Exploitation of Urban Heat Island (GWHPs) .......................................................................... 13 2.3 Qualitative methods for the evaluation of shallow geothermal potential (BHEs) ................ 14 2.3.1 Geothermal potential of the province of Treviso (Veneto, NW Italy) ........................... 14 2.4 The G.POT (Geothermal POTential) method (BHEs) ............................................................. 15 2.5 Density of closed-loop geothermal systems (BHEs) .............................................................. 16 2.5.1 The Westminster (London) case study (Zheng et alii, 2015) ......................................... 16 2.5.2 The Barcelona case study (Garcìa-Gil et alii, 2015) ....................................................... 17 2.6 Qualitative open-loop geothermal potential evaluation methods ....................................... 18 2.6.1 BRGM multi-criteria weighted score systems ............................................................... 19 2.7 Maximum thermal power to be installed in a GWHP ........................................................... 21 2.7.1 The Barcelona case study (Garcìa-Gil et alii, 2015) ....................................................... 21 2.7.2 The Cuneo case study (Casasso and Sethi, 2017) .......................................................... 22 3 Methods adopted for the geothermal potential estimation in the case study areas ................... 25 3.1 Closed loop: G.POT ................................................................................................................ 25 3.1.1 Mathematical method ................................................................................................... 25 3.1.2 Common modelling assumption and input parameter sets adopted ........................... 26 3.1.3 Economic impact of closed-loop geothermal potential ................................................ 27 3.2 Open loop: assessment of technically feasible flow rates .................................................... 29 3.3 Access to the geothermal potential maps of the project ...................................................... 31 4 NSGE mapping in Aosta Valley (Italy) ............................................................................................ 32 4.1 The territory surveyed ........................................................................................................... 32 4.1.1 Existing geothermal installations .................................................................................. 32 2/137 GRETA is co-financed by the European Regional Development Fund through the Interreg Alpine Space programme. See more about GRETA at www.alpine-space.eu/projects/greta. Local-scale maps of the NSGE potential in the Case Study areas 4.1.2 Geological setting .......................................................................................................... 33 4.1.3 Hydrogeological setting of the Aosta plain ................................................................... 34 4.2 Closed-loop geothermal potential ........................................................................................ 39 4.2.1 Thermal properties of the ground ................................................................................. 39 4.2.2 Ground temperature ..................................................................................................... 41 4.2.3 Length of the heating season ........................................................................................ 42 4.2.4 Results ........................................................................................................................... 44 4.2.5 Comparison of G.POT with other closed-loop potential mapping methods ................. 45 4.3 Open-loop geothermal potential .......................................................................................... 46 4.3.1 Methodological remarks ............................................................................................... 46 4.3.2 Results ........................................................................................................................... 47 4.4 Conclusions ............................................................................................................................ 51 5 NSGE mapping in Cerkno (Slovenia) .............................................................................................. 52 5.1 The territory surveyed ........................................................................................................... 52 5.1.1 Geological and hydrogeological setting ..................................................................... 55 5.1.2 Existing geothermal installations ............................................................................... 56 5.2 Closed-loop geothermal potential ........................................................................................ 57 5.2.1 Thermal properties of the ground ................................................................................. 57 5.2.2 Ground temperature ................................................................................................... 61 5.2.3 Length of the heating season ...................................................................................... 63 5.2.4 Results ........................................................................................................................... 67 5.3 Conclusions ............................................................................................................................ 69 6 NSGE mapping in Oberallgäu (Germany) ...................................................................................... 70 6.1 The territory surveyed ........................................................................................................... 71 6.1.1 Geological setting .......................................................................................................... 71 6.1.2 Hydrogeological setting ................................................................................................. 73 6.2 Open-loop geothermal potential .......................................................................................... 77 6.3 Conclusions ...........................................................................................................................