Vertical borehole ground source heat pumps use heat stored in the ground, and groundwater.  That heat comes from the sun, and, to a far lesser extent, heat generated within the earth as well as human-generated heat from buildings, underground railways and other constructions.   It may also come from a cooling system, where heat from a building is discharged through boreholes to be stored underground during the summer before being extracted the following winter.

This heat can affect the underground environment including the geochemistry of the aquifer and microbiological ecosystems.  When there are multiple systems in an area, they may interfere with each other, particularly if there is groundwater involved.  Therefore there are two main policy concerns here – protection of the underground environment, and equitable use of the heat storage resource.   With increasing numbers of these systems being installed in London(1), and their inclusion in the Renewable Heat Incentive, it seems important that someone be responsible for managing it all.  Sadly, noone is.

Earlier this week, I went to a meeting of the UK Groundwater Forum, a hydrogeology group, on ‘Groundwaters Role In Reducing Our Carbon Footprint’.   Among many interesting talks were two that touched on the subject of the way we manage the underground heat resource in our aquifers (2)

Richard Shennan of Mott MacDonald Fulcrum talked about the ground source heating and cooling project which is underway on the 1851 commission lands in Kensington, providing heating and cooling for the V&A, Imperial College and other sites in the area.  As part of the design for that project, maps of underground heat are being produced showing the heat flow through the aquifer as it changes through the seasons.  Of course, they’re restricted to that site only, and it was suggested that it would be useful to see similar maps for all installations.

Anna Hall of the Environment Agency discussed the regulatory environment, and in particular pointed out that the environment agency have no jurisdiction over heat because it is not a ’substance’ that can be released into the environment.  This means that while open loop systems need to have abstraction and discharge licences, closed loop systems do not.  The EA are apparently encouraging the Ground Source Heat Pump Association to set up a register of systems, but have neither the funding nor the power to do anything themselves.

This needs to change.  It seems that there are a few bodies which could reasonably administer ground source heating systems, given the funding and powers to do so.

The Environment Agency, who are already responsible for water, would be ideally placed.  They have the hydrogeological expertise, are already administering water consents and are charged with protecting the environment and contributing to sustainable development.

Local councils, are already responsible for planning, including the inclusion of renewable energy in new buildings under the Merton Rule which is the motivation for many GSHP installations.  Unfortunately, they probably lack the necessary technical expertise, but perhaps something could be done in specific areas, such as London, with the London Development Agency taking a role alongside its Decentralised Energy and Energy Masterplanning project.  That project, which is mapping heating demand in London, would seem to have a good synergy with managing and mapping heating supply.

Finally, the GSHP association could no doubt administer a register and at least have access to the technical expertise, but they are a trade body, who’s aim is to promote the industry in the UK.  Any regulatory role would give them an unreasonable conflict of interest.

Underground heat capacity will be an important resource in the near future if we are to reduce our carbon footprint and make our cities sustainable.  It needs to be managed for the good of the environment, and the fair use of the resource by those who need it.  The Environment Agency, or perhaps bodies such as the London Development Agency, are best placed to do this.

(1 ) Gropius, M., 2010. Numerical groundwater flow and heat transport modelling of open-loop ground source heat systems in the London Chalk. Quarterly Journal of Engineering Geology and Hydrogeology, 43(1), 23-32. Available at: http://qjegh.lyellcollection.org/cgi/content/abstract/43/1/23. 

(2) The talks aren’t available online yet, but should be soon at the conference site http://www.groundwateruk.org/Groundwaters_role_in_reducing_our_carbon_footprint.aspx