Techno-Economic Mapping for the Improvement of Shallow Geothermal Management in Southern Switzerland
Abstract
:1. Introduction
1.1. Closed-Loop Systems in Cantone Ticino Diffusion And Licensing Process
1.2. Low Enthalpy Geothermal Potential Mapping in Literature
2. Natural Resource
2.1. Mean Annual Air Temperature (MAAT) and Ground Surface Temperature (GST) Mapping
2.2. Subsurface Thermal Characterization
2.2.1. Outcrops
2.2.2. Unconsolidated Materials
3. Technological Constraints
3.1. Target GSHP System Characteristics
3.2. Hypothesized Energy Demand
4. Results
4.1. Required BHE Length Calculation
4.2. Economical Maps
4.2.1. Total Installation Costs and CHF/Kw
4.2.2. MATLAB/Octave Tool for Payback Period Estimate
4.3. CO2 Savings
4.4. Comparison of Produced Techno-Economic Maps with Available Regulation Maps
5. Discussion
- Widening of allowable areas: would promote the installation in new areas, but this would result in an increase of new requests, posing a serious threat to groundwater quality (from a chemical and thermal standpoint);
- Creation of large shallow geothermal systems that could do thermal storage plus district-heating: by creating new shallow geothermal installations in areas with high geo-exchange potential and by delivering the produced heat to areas having lower potential could optimize the management of the resource, since less geothermal systems in low potential areas would be needed. This solution could imply the use of Borehole Thermal Energy Storage systems, constituted of a large number of geothermal probes with short mutual spacing, which is beneficial in order to avoid leakage of heat/“cold” outside the borehole array [36].
Supplementary Materials
Author Contributions
Funding
Acknowledgments
Conflicts of Interest
Abbreviations and Symbols
SUPSI | Scuola Universitaria Professionale della Svizzera Italiana |
GSHP | Ground Source Heat Pumps |
COP/EER | Coefficient of Performance/Energy Efficiency Ratio |
MAAT/GST | Mean Annual Air Temperature/Ground Surface Temperature |
MAE | Mean Absolute Error |
RMSE | Root-Mean-Square Error |
k | Hydraulic conductivity |
λ | Thermal conductivity |
TRT | Thermal Response Test |
BHE | Borehole Heat Exchanger |
EED | Earth Energy Designer |
DHW | Domestic Hot Water |
SPF | Seasonal Performance Factor |
CHF | Swiss franc |
NPV | Net Present Value |
References
- Lund, J.W.; Boyd, T.L. Direct utilization of geothermal energy 2015 worldwide review. Geothermics 2016, 60, 66–93. [Google Scholar] [CrossRef]
- Swiss Federal Office of Energy SFOE. Available online: http://www.bfe.admin.ch/index.html?lang=en (accessed on 10 January 2019).
- MINERGIE®. Available online: https://www.minergie.ch/fr/certifier/minergie/?l (accessed on 10 January 2019).
- Perego, R.; Guandalini, R.; Fumagalli, L.; Aghib, F.S.; de Biase, L.; Bonomi, T. Sustainability evaluation of a medium scale GSHP system in a layered alluvial setting using 3D modeling suite. Geothermics 2016, 59, 14–26. [Google Scholar] [CrossRef]
- Consiglio di Stato Della Repubblica e Cantone Ticino, Regolamento Sull’utilizzazione Dell’energia (RUEn). 2008. (In Italian). Available online: https://www3.ti.ch/CAN/RLeggi/public/index.php/raccolta-leggi/legge/vid/09_36 (accessed on 10 January 2019).
- Overview on Cantone Ticino’s Energy, Cantonal Office of Statistics, February 2018. Available online: https://www3.ti.ch/DFE/DR/USTAT/allegati/prodima/4308_energia.pdf (accessed on 10 January 2019).
- Environment Division, Office of water Protection and Water Supply, State Council Proceedings 2016–Statistical Annex (Public Report). Available online: https://m4.ti.ch/fileadmin/CAN/TEMI/RENDICONTOCDS/2016/RENDICONTO/Allegato_statistico_2016_documento_completo.pdf (accessed on 10 January 2019).
- GESPOS. Available online: https://geoservice.ist.supsi.ch/gespos/ (accessed on 10 January 2019).
- Swiss Waters Protection Ordinance (WPO). 2010. Available online: https://www.admin.ch/opc/en/classified-compilation/19983281/index.html (accessed on 10 January 2019).
- Swiss Federal Office for the Environment FOEN, Exploitation de la Chaleur Tirée du Sol et du Sous-Sol. 2009. Available online: https://www.bafu.admin.ch/bafu/fr/home/themes/eaux/publications/publications-eaux/exploitation-chaleur-tiree-sol-sous-sol.html (accessed on 10 January 2019).
- Thüring, M. Regolamentazione Dello Sfruttamento Dell’energia Geotermica nel Canton Ticino, Sezione per la Protezione Dell’aria, Dell’acqua e del Suolo, Canton Ticino. 2006; (internal report). [Google Scholar]
- Lopez, A.; Roberts, B.; Heimiller, D.; Blair, N.; Porro, G. US Renewable Energy Technical Potentials: A GIS-Based Analysis; United States National Renewable Energy Laboratory (NREL): Golden, CO, USA, 2012.
- Schiel, K.; Baume, O.; Caruso, G.; Leopold, U. GIS-based modelling of shallow geothermal energy potential for CO2 emission mitigation in urban areas. Renew. Energy 2016, 86, 1023–1036. [Google Scholar] [CrossRef]
- García-Gil, A.; Vázquez-Suñe, E.; Alcaraz, M.M.; Juan, A.S.; Sánchez-Navarro, J.Á.; Montlleó, M.; Rodríguez, G.; Lao, J. GIS-supported mapping of low-temperature geothermal potential taking groundwater flow into account. Renew. Energy 2015, 77, 268–278. [Google Scholar] [CrossRef]
- Bertermann, D.; Klug, H.; Morper-Busch, L. A pan-European planning basis for estimating the very shallow geothermal energy potentials. Renew. Energy 2015, 75, 335–347. [Google Scholar] [CrossRef]
- Gemelli, A.; Mancini, A.; Longhi, S. GIS-based energy-economic model of low temperature geothermal resources: A case study in the Italian Marche region. Renew. Energy 2011, 36, 2474–2483. [Google Scholar] [CrossRef]
- Casasso, A.; Sethi, R. Assessment and mapping of the shallow geothermal potential in the province of Cuneo (Piedmont, NW Italy). Renew. Energy 2017, 102, 306–315. [Google Scholar] [CrossRef]
- Arola, T.; Eskola, L.; Hellen, J.; Korkka-Niemi, K. Mapping the low enthalpy geothermal potential of shallow Quaternary aquifers in Finland. Geotherm. Energy 2014, 2, 9. [Google Scholar] [CrossRef] [Green Version]
- Viesi, D.; Galgaro, A.; Visintainer, P.; Crema, L. GIS-supported evaluation and mapping of the geo-exchange potential for vertical closed-loop systems in an Alpine valley, the case study of Adige Valley (Italy). Geothermics 2018, 71, 70–87. [Google Scholar] [CrossRef]
- Galgaro, A.; di Sipio, E.; Teza, G.; Destro, E.; de Carli, M.; Chiesa, S.; Zarrella, A.; Emmi, G.; Manzella, A. Empirical modeling of maps of geo-exchange potential for shallow geothermal energy at regional scale. Geothermics 2015, 57, 173–184. [Google Scholar] [CrossRef] [Green Version]
- Hellström, G.; Sanner, B. Earth Energy Designer 3.2. Manual. Available online: https://www.buildingphysics.com/manuals/EED3.pdf (accessed on 10 January 2019).
- SIA Schweizerischer Ingenieur- und Architekten-Verein. Sondes Géothermiques, 1st ed.; SIA: Zurich, Switzerland, 2010. [Google Scholar]
- MeteoSwiss. Available online: https://www.meteoswiss.admin.ch/ (accessed on 10 January 2019).
- Signorelli, S.; Kohl, T. Regional ground surface temperature mapping from meteorological data. Glob. Planet. Chang. 2004, 40, 267–284. [Google Scholar] [CrossRef]
- IDAWEB. Available online: https://gate.meteoswiss.ch/idaweb/login.do (accessed on 10 January 2019).
- Federal Office of Topography Swisstopo. Available online: https://www.swisstopo.admin.ch/ (accessed on 10 January 2019).
- Linda, S. Interplay between Opposite Vergence Thrusts along the Southern Alps Margin in Canton Ticino (Switzerland): Geometry and Kinematics in Support of the Characterization of Geothermal Potential. Ph.D. Thesis, Pavia, Italy, 2015. [Google Scholar]
- Luo, J.; Tuo, J.; Huang, W.; Zhu, Y.; Jiao, Y.; Xiang, W.; Rohn, J. Influence of groundwater levels on effective thermal conductivity of the ground and heat transfer rate of borehole heat exchangers. Appl. Therm. Eng. 2018, 128, 508–516. [Google Scholar] [CrossRef]
- Freeze, R.A.; Cherry, J.A. Groundwater; Prentice-Hall: Englewood, NJ, USA, 1979. [Google Scholar]
- Fetter, C.W. Applied Hydrogeology, 4th ed.; Prentice Hall: Upper Saddle River, NJ, USA, 2001. [Google Scholar]
- Federal Office of Statistics, Statistics of Buildings and Residential Buildings, Neuchâtel. Available online: http://www3.ti.ch/DFE/DR/USTAT/allegati/prodima/4509_costruzioni_e_abitazioni.pdf (accessed on 10 January 2019).
- Republic and Cantone Ticino–Cantonal Energetic Plan. Available online: http://www4.ti.ch/generale/piano-energetico-cantonale/tema/tema/ (accessed on 10 January 2019).
- MATLAB. Available online: https://www.mathworks.com/products/matlab.html (accessed on 10 January 2019).
- GNU OCTAVE. Available online: https://www.gnu.org/software/octave/ (accessed on 10 January 2019).
- Swiss Federal Office for the Environment FOEN. Compilation of the CO2 Emission Factors and Energy Content of the Various Energy Sources that Are Used in the Greenhouse Gas Inventory; Swiss Federal Office for the Environment FOEN: Ittigen, Switzerland, 2016.
- Banks, D. An Introduction to Thermogeology: Ground Source Heating and Cooling; John Wiley & Sons: Hoboken, NJ, USA, 2012. [Google Scholar]
Type of System | üB | Au | Zu | Area | S3 | S2 | S1 |
---|---|---|---|---|---|---|---|
Geothermal probes (vertical systems) | + | b | − | − | − | − | |
Underground circuits (horizontal systems) | + | +4 | −2/4 | −b/5/4/7 | − | − | |
Geothermal piles and other thermo-active elements | + | b | −2/4 | −b | − | − | |
Wells for groundwater withdrawal, for heating and cooling | + | b | − | − | − | − | |
Coaxial wells | −6 | −6 | − | − | − | − |
Station Name | Spatial Information | Normal Period: 1981–2010 (Datum: WGS 84) | ||
---|---|---|---|---|
Latitude (Decimal Degrees) | Longitude (Decimal Degrees) | Altitude (m a.s.l.) | Measured MAAT (°C) | |
Lugano | 46.0042 | 8.9603 | 273 | 12.4 |
Stabio | 45.8434 | 8.9323 | 353 | 11.1 |
Cimetta | 46.2004 | 8.7916 | 1661 | 5.2 |
Locarno Monti | 46.1724 | 8.7875 | 367 | 12.4 |
Magadino/Cadenazzo | 46.1600 | 8.9336 | 203 | 11.4 |
Grono | 46.2550 | 9.1637 | 324 | 12.4 |
Acquarossa/Comprovasco | 46.4595 | 8.9354 | 575 | 9.9 |
Piotta | 46.5148 | 8.6880 | 990 | 7.7 |
S.Bernardino | 46.4635 | 9.1846 | 1639 | 3.9 |
Site Name | Lat. (DD, WGS84) | Long. [DD, WGS 84] | Altitude (m a.s.l.) | Undisturbed Ground Temperature from TRT (°C) | Estimated MAAT from Map (°C) | Absolute T Discrepancy (°C) |
---|---|---|---|---|---|---|
Barbengo | 45.9596 | 8.9197 | 283 | 14.4 | 12 | 2.4 |
Collina d’oro | 45.9631 | 8.9083 | 526 | 11.8 | 10.7 | 1.1 |
Lugano-Besso | 46.0094 | 8.9380 | 378 | 14.8 | 11.5 | 3.3 |
Massagno | 46.0115 | 8.9423 | 367 | 14.8 | 11.6 | 3.2 |
Mendrisio | 45.8642 | 8.9824 | 356 | 12.7 | 11.6 | 1.1 |
Olivone (estimated coordinates) | 46.5181 | 8.8842 | 1433 | 8.3 | 5.5 | 2.8 |
DATA SOURCE: various TRT executed in-situ between 2010 and 2015 | MAE: 2.3 °C | RMSE: 2.5 °C |
Site Name | Lat. (DD, WGS84) | Long. (DD, WGS84) | Altitude (m a.s.l.) | Consistency | Measured GST (°C) | Mapped GST (°C) | Absolute Discrepancy (°C) |
---|---|---|---|---|---|---|---|
Acquarossa/Comprovasco | 46.4594 | 8.9356 | 575 | Average value for 3 years | 10.6 | 11.9 | 1.3 |
Locarno monti | 46.1725 | 8.7874 | 366 | Average values for 9 years | 13.6 | 13.1 | 0.5 |
Magadino/Cadenazzo | 46.1600 | 8.9336 | 203 | Average value for 12 years | 12.7 | 14.0 | 1.3 |
Robiei | 46.4430 | 8.5133 | 1896 | Average value for 6 years | 5.1 | 7.1 | 2.0 |
Stabio | 45.8433 | 8.9323 | 353 | Average value for 4 years | 11.8 | 13.2 | 1.4 |
Data source: IDAWEB [25] | MAE: 1.3 °C | RMSE: 1.4 °C |
Lithology | λ (W/mK) | Data Source |
---|---|---|
Greenschists, amphibolites, metagabbro, meta-ultrabasite | 2 | Averaged from SIA 384/6 |
Pelitic and psammitic gneiss, fillads, conglomerates, sandstone | 2.6 | Averaged from SIA 384/6 |
Dolomite and dolomitic marble | 3.17 | Lab. measurements Soma, 2015 |
Granite, granodiorite | 2.8 | SIA 384/6 |
Acid and basic vulcanites | 2.36 | Lab. measurements Soma, 2015 |
Granite gneiss | 2.7 | SIA 384/6 |
Generic Quaternary deposits | 2 | Representative value SIA 384/6 |
Variogram | Double Comparison Statistics | |||
---|---|---|---|---|
Parameter | Value | Cross Validation | Surveys Data | |
Nugget | 0.247 | N° of data | 555 | 409 |
Range (m) | 1514 | Max Abs error (logk) | 3.51 | 2.26 |
Sill (Partial) | 4.08 (0.161) | Min Abs error (logk) | 0.00039 | 0.000704 |
Model | Spherical | Average error (logk) | 0.00076 | −0.09371 |
Lag size (m) | 322.3 | MAE (logk) | 0.46 | 0.49 |
N° of lags | 12 | MSE (logk) | 0.37 | 0.43 |
Neighbors to include | 30 | RMSE (logk) | 0.61 | 0.66 |
- | - | NRMSE (logk) | 0.11 | 0.15 |
Input | Parameter | Value | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Heat exchanger and perforation | Probe type | Double-U tube | ||||||||||
Configuration | 2 × 2 (N° 233)—4 probes | |||||||||||
Distance | 8 m | |||||||||||
Borehole diameter | 130 mm | |||||||||||
Grouting thermal conductivity | 1 W/mK | |||||||||||
Volumetric flow rate | 2 l/s per probe | |||||||||||
Probe external diameter | 32 mm | |||||||||||
Thickness | 3 mm | |||||||||||
Probes thermal conductivity | 0.420 W/mK | |||||||||||
Distance between internal tubes | 80 mm | |||||||||||
Thermo-vector fluid | Thermal conductivity | 0.48 W/mK | ||||||||||
Specific heat | 3795 J/kgK | |||||||||||
Density | 1052 kg/m3 | |||||||||||
Viscosity | 0.0052 kg/ms | |||||||||||
Freezing point | −14 °C | |||||||||||
Probes thermal resistance | Constant values
| 0.140 mK/W 0.450 mK/W | ||||||||||
Heating capacity | - | 25 kW | ||||||||||
Performance Energetic demand | SPF Annual heating demand (comprises HSW) | 4 30 MWh 22.5 MWh/year provided by ground 7.5 MWh/year provided by heat pump | ||||||||||
Jan. | Feb. | Mar. | Apr. | May | Jun. | Jul. | Aug. | Sept. | Oct. | Nov. | Dec. | |
Heating demand [MWh/month] | 4.65 | 4.44 | 3.75 | 2.97 | 1.92 | 0 | 0 | 0 | 1.83 | 2.61 | 3.51 | 4.32 |
Peak monthly heating duration [hours/month] | 6 | 5 | 5 | 3 | 3 | 0 | 0 | 0 | 3 | 3 | 5 | 6 |
Statistic | Value |
---|---|
Max abs error | 52 m/kW |
Min abs error | 1 m/kW |
Average error | 3.7 m/kW |
Mean abs error | 6 m/kW |
Abs average error (%) | ±23% |
Parameters | Hard Rock | Consolidated Sedimentary Rock | Unconsolidated Material |
---|---|---|---|
Drillability (CHF/m) | 91.2 | 105.2 | 101.5 |
Heat Pump: cost per kW (CHF/kW) * | 1000 | ||
Probe cost (CHF/m) ** | 15.7 | ||
Grouting (CHF/m) *** | 6.6 |
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Perego, R.; Pera, S.; Galgaro, A. Techno-Economic Mapping for the Improvement of Shallow Geothermal Management in Southern Switzerland. Energies 2019, 12, 279. https://doi.org/10.3390/en12020279
Perego R, Pera S, Galgaro A. Techno-Economic Mapping for the Improvement of Shallow Geothermal Management in Southern Switzerland. Energies. 2019; 12(2):279. https://doi.org/10.3390/en12020279
Chicago/Turabian StylePerego, Rodolfo, Sebastian Pera, and Antonio Galgaro. 2019. "Techno-Economic Mapping for the Improvement of Shallow Geothermal Management in Southern Switzerland" Energies 12, no. 2: 279. https://doi.org/10.3390/en12020279
APA StylePerego, R., Pera, S., & Galgaro, A. (2019). Techno-Economic Mapping for the Improvement of Shallow Geothermal Management in Southern Switzerland. Energies, 12(2), 279. https://doi.org/10.3390/en12020279