18. Strategic Implications of a Banchory Geothermal Project
While it has long been appreciated that the Eastern Grampian granite plutons of Scotland represent a potential source of energy, no specific proposals have yet reached the stage at which this project has now placed the Hill of Fare pluton. This has only been realised in this case because of the pre-existence of a successful heat network at Hill of Banchory, which has facilitated concrete consideration of quite what it would take to harness geothermal heat from granite for district heating purposes. This project is therefore, in itself, a strategic development in the context of Scotland's wider quest for affordable low-carbon and renewable heat.
Clearly there is scope to use this project's findings as a template for similar, site-specific appraisals of the prospects for community and industrial (e.g. for whisky production) use of the heat in similar (and in many cases even more promising) granites elsewhere in Aberdeenshire and adjoining districts. Most of the towns in this region are not connected to the gas grid, and there is not scope in all of them to exploit sustainable local wood supplies for biomass-based district heating. Geothermal probably represents the single best hope of simultaneously combatting fuel poverty and carbon emissions from heat in those towns. As demonstrated in Chapter 15, this could amount to 70% or more of the total heat demand in this region, and in excess of 5% of the total heat demand of Scotland.
In addition, there are other regions of Scotland where radiothermal granites may be present in the deep subsurface (e.g. xenoliths in volcanic plugs in the Midland Valley include notable examples of suitably potassium-rich granites, indicating the likely presence of plutons of that nature at depth; see Younger et al. 2012). Indeed, the occurrence of such granites at depth might explain the relatively high heat flows in the sedimentary basins of the Midland Valley, providing a link to the Deep Sedimentary Aquifer prospects in that region.
If the Banchory project is taken to the next stage (see Chapter 19), the strategic value for Scotland will be considerable. But the strategic value will also extend into adjoining regions (e.g. the North Pennines and Lake District of England, where similar granites have been investigated in recent years) as well as into Northern Ireland, where the Mourne Granite has recently been recognised as an exceptionally high heat-producer.
Wider afield, the European Union continues to invest considerable sums in geothermal R&D, such as the Horizon 2020 DESTRESS project which commences on March 1 st 2016 (in which the University of Glasgow participants in this consortium are the UK partners), which is addressing optimal reservoir stimulation techniques for radiothermal granites and other deep geothermal prospects. Thus timely execution of the proposed next steps of this project would allow Banchory, and therefore Scotland, to contribute at the very forefront of European (and thus global) R&D and demonstration of geothermal energy technology.
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