1. © NERC All rights reserved Potential geothermal opportunities in Scotland Martin Gillespie British Geological Survey

2. © NERC All rights reserved Heat flow The standard measure of the amount of heat moving through the subsurface Values for Scotland are low, but they probably underestimate the true size of the heat resource because they were made in the near-surface (climate-affected) zone

3. © NERC All rights reserved Temperature (ºC) Depth (m) Onshore boreholes Offshore boreholes 30.5 ºC/km 46.7 ºC/km

4. © NERC All rights reserved Abandoned mine workings Hot Sedimentary Aquifers (HSA) Hot Dry Rocks (HDR) Concepts for exploiting deep geothermal energy in Scotland

5. © NERC All rights reserved Hot Sedimentary Aquifers Require bodies of permeable rock (aquifers) at depth Likely to yield water in the range 20-80 ºC Since 1986, a combined heat and power system in Southampton has exploited an HSA The largest and most productive aquifers are in sedimentary strata

6. © NERC All rights reserved Potential HSA prospects in Scotland

7. © NERC All rights reserved Hot Dry Rock concept Needs an Engineered Geothermal System (EGS) to exploit the energy Heat energy sufficient to generate electricity Intrusions of granite are the best prospects, especially High Heat Production (HHP) granite Requires a body of impermeable rock at depth

8. © NERC All rights reserved Potential HDR prospects in Scotland Exposed intrusions of HHP granite Areas most likely to overlie buried intrusions of HHP granite

9. © NERC All rights reserved