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Hill of Banchory Geothermal Energy Project Feasibility Study Report

Official Print Publication Date
Website Publication DateMarch 23, 2016


ISBN 978 1 78652 075 3 (Web only publication)
PPDAS 66920

This document is also available in pdf format (5.3MB)

Photo: courtesy Leys Estate
Photo: courtesy Leys Estate

This report was funded by and prepared for the Scottish Government under the Geothermal Energy Challenge Fund, part of the Low Carbon Infrastructure Transition Programme (LCITP).

The report was written by the Hill of Banchory Geothermal Energy Consortium, an ad hoc team with the following membership:

Guy Milligan MEI, Director, Hill of Banchory ESCo Limited
George Wood FCIOB AaPS , Director, Jigsaw Energy
Professor Paul Younger FREng FICE, FGS, C.Eng., C.Geol., Rankine Chair of Engineering, Professor of Energy Engineering, University of Glasgow (contributor and editor)
Dr Michael Feliks, UK Operations Manager, Cluff Geothermal Ltd.
Dr Alistair McCay, Research Assistant, University of Glasgow
Dr Martin Gilliespie, British Geological Survey
Paul Steen CEng MICE, Associate Director, Ramboll Energy
Neil McBeth, Ramboll Energy
David Townsend, MD, Town Rock Energy
Phil Townsend, Chief Associate, Town Rock Energy
Professor Randell Stephenson, Chair in Geology & Petroleum Geology, University of Aberdeen
Dr Enrique Gomez-Rivas, Lecturer in Geology & Petroleum Geology, University of Aberdeen



Executive Summary

1. Introduction

2. Background to Deep Geothermal Technology

3. The Hill of Banchory Biomass Heat Network

4. Geological Background

5. Provisional Borehole Design

6. Expanding the database: additional survey work on the Hill of Fare granite
6.1. Heat Production
6.2. Temperature Projections
6.3. Thermal Conductivity
6.4. Gravity and Magnetic Surveying

7. Assessment of Existing Baseline Data

8. Vision Statement - A Deep Geothermal Heat System at Hill of Banchory

9. The potential market for a geothermal well; heat demand in Banchory

10. The Economics of the Geothermal Well

11. Integrating the Upstream and Downstream Economic Models

12. Preliminary Heat Network Design Considerations

13. Risk Strategy

14. Deep Geothermal Regulation

15. Carbon Emissions Savings

16. Community Engagement

17. Conclusion and Recommendations

18. Strategic Implications of a Banchory Geothermal Project

19. Next Steps


Appendix 1: Thermal Conductivity Data
Appendix 2: Network Heat Cost Model Input Variables
Appendix 3: Risk Register
Appendix 4: Heat Production Data for the Hill of Fare Granite

List of Figures

Figure 1: Location of granite bodies in north east Scotland and the heat flow boreholes used to estimate geothermal potential (modified by Rob Westaway from Fig. 2.1 of Wheildon et al. (1984), and used with his permission).
Figure 2: Schematic of a generic geothermal borehole doublet system
Figure 3: (a) Geothermal drilling in Newcastle upon Tyne in 2011 (b) Geothermal wellhead at the Southampton scheme. This photo was taken during maintenance work; usually the wellhead is encased in insulation and is even less conspicuous.
Figure 4: Local Wood Chips Production near Banchory (photo: Guy Milligan)
Figure 5: Hill of Banchory Biomass Heat Network Development to Date
Figure 6: Heat Network Plan
Figure 7: Hill of Banchory Energy Centre Plant Room (photo: Guy Milligan)
Figure 8: Generalised bedrock geology of the ground west of Aberdeen.
Figure 9: Bedrock geology of the Banchory district.
Figure 10: Bedrock geology of the Hill of Fare Granite Pluton
Figure 11: Polished surface of a block of Hill of Fare 'main granite'
Figure 12: Location of plutons assigned to the Cairngorm Suite
Figure 13: Schematic profile of drilled and cased diameters and cement runs for the range of possible geologies (i.e. allowing for a section through the Dalradian) that could be drilled at Banchory
Figure 14: Geothermal Gradient Prediction Scenarios for Hill of Fare Granite
Figure 15: Estimated thermal conductivity, Hill of Fare
Figure 16: (a) Regional Gravity [left-side image], (b) Magnetic Anomalies [right-side image] for a part of north-eastern Scotland (BGS Data (2002))
Figure 17: Location of the observed gravity and magnetic profiles
Figure 18: Locations of gravity stations along the track from the main road (A980) to Burnhead Farm
Figure 19: Gravity anomalies along the (westerly) profile shown in Figure 17
Figure 20: Magnetic anomalies along the (easterly) profile shown in Figure 17
Figure 21: Theoretical effect in the induced magnetic field of the contact of a magnetic body and a non-magnetic one
Figure 22: Examples of Fracture Systems in granites
Figure 23: Fracture Density calculated from borehole cores of the high heat production East Grampian granites
Figure 24: Granite Plutons in Scotland
Figure 25: Geothermal wellfield in Reykjavik. The wells are in inconspicuous cabins about the size of bus shelters
Figure 26: Future Hill of Banchory Heat Network Expansions
Figure 27: Heat Demand Density Analysis for Banchory
Figure 28: Proposed Heat Networks in Banchory
Figure 29: Biomass fuel at the Hill of Banchory Biomass Energy Centre
Figure 30: Indicative Cost of Heat Model Outputs
Figure 31: Required heat sales for the geothermal well to be financially viable
Figure 32: Commercial RHI Biomass Tariffs as of January 2016
Figure 33: Demand projections for the Hill of Banchory Heat Network

Figure 34: Cost of heat model cumulative expansion results for proposed Banchory networks
Figure 35: Heating System Decision Flow Chart
Figure 36: Simplified system schematic for direct geothermal heating in Banchory
Figure 37: Unbalanced flow heat exchanger to increase source-side temperature drop
Figure 38: Risk Matrix
Figure 39: Risk Matrix Post-Mitigation
Figure 40: maximum area in which heat demand could be met from geothermal heat from radiothermal granites

List of Tables

Table 1: Heat Production Values for the Hill of Fare Granite, Hill of Fare Microgranite and the neighbouring Crathes Granodiorite
Table 2: Heat Flow Estimates of the High Heat Production East Grampian Granites
Table 3: Heat Flow, Heat Production and Thermal Conductivity Estimates for Hill of Fare Granite
Table 4: Depth to Typical Target Temperatures

Table 5: Lifetime Corrected K Values
Table 6: Assumed flow rate scenarios for a borehole-doublet scheme in fractured granite
Table 7: Future Expansions for the Hill of Banchory Heat Network
Table 8: District Heating Network Analysis
Table 9: Estimated flow rates for the Hill of Fare granite at Banchory
Table 10: Estimated heat available from geothermal resources for given flow rates and temperature drops
Table 11: Heat sales required to reach 10% and 20% IRR for wells of differing capacities
Table 12: Summary and Evaluation of heating solutions for potential heat production scenarios at the Hill of Fare