ATESHAC is a broad, multidisciplinary project that brings together research on the geoscience and geoengineering of ATES, life-cycle assessment of the economic and decarbonisation potential of ATES, and responsible innovation, including societal engagement.
The research programme has been subdivided into six separate but inter-related work packages:
WP1: ATES national capacity: distribution and demand
Key science questions: What is the UK national capacity of ATES and its spatial distribution and alignment with heating/cooling demand?
We are identifying ATES capacity across UK based on integration and interrogation of existing data (geological models, borehole data including geophysical and lithological logs, flow tests, water samples and any other available data). BGS has access to a unique and comprehensive archive of data and we are building on their earlier work mapping the subsurface resource in England and Wales for installation of ground source heat pumps. At the same time, we are quantifying demand for heating/cooling across the UK in collaboration with National Grid. The resulting maps are being integrated to quantify the alignment between ATES demand and capacity. The work quantifies the ‘size of the prize’ in the UK national context.
WP2: Aquifer response to heat and cool storage
Key science questions: What is the subsurface response (physical/chemical) to heat/cool storage and abstraction? What are the key aquifer properties controlling storage capacity and how do they impact storage efficiency, and what is their spatial distribution in a key UK aquifer? What (if any) are the associated environmental risks with storing and abstracting heat/cool?
Uncertainty in aquifer properties, and in the subsurface response to ATES, can be a key barrier to deployment: it creates risk for developers, and for permitting and planning authorities who may be obliged to enforce tight operational constraints to satisfy the precautionary principle. WP2 uses field and laboratory experiments to address these science questions, centred on the Sherwood aquifer beneath UKGEOS Cheshire, which provides a unique test site for subsurface operations. The Sherwood is a major, UK-wide aquifer unit.
Laboratory experiments are being undertaken in a coordinated programme at UKGEOS, BGS and UoM. Continuous core-scale datasets of geophysical, mineralogical, and geochemical characteristics are being obtained, and targeted, high-definition optical, CT and XRF data acquired using the core scanning facility (CSF) at UKGEOS. Laboratory-based thermal conductivity and volumetric heat capacity tests on rock samples selected to span the observed variability are being run at the National Geological Repository at BGS.
UoM focusses on characterising the pore- to core-scale storage capacity and response to cyclical heating and cooling. Pore-scale dynamic imaging of chemical (e.g. mineral precipitation and dissolution) and physical (e.g. deformation, fines generation and migration) reactions with groundwater can be observed using UoM’s bespoke X-ray CT setup, in conjunction with analysis of effluent water composition. These tests are being performed using a range of groundwater chemistry, reflecting the compositional stratification observed in the Sherwood aquifer and the potential for ATES-induced mixing.
Field experiments will use the bespoke Thermal Response Testing (TRT) borehole array at UKGEOS, to determine the thermal capacity of the Sherwood aquifer. Active, open-hole DTS heat tracer tests will run in the TRT array and provide data describing heat flow and dispersal in the aquifer. The effect on the subsurface environment, including seismicity and migration of the heat plume, will be monitored in real time by a suite of passive microseismic and shallow geophysical experimental arrays.
WP3: ATES system operability and efficiency
Key science questions: How can ATES systems be optimised for capacity and efficiency while maintaining thermal balance? What is the impact of aquifer heterogeneity on capacity and efficiency? How do multiple ATES deployments interact? What is the potential for ATES systems to modify groundwater composition?
Deployment risks for ATES arise because there is uncertainty in the response of the aquifer, and in how the deployment may interact with other subsurface functions. Moreover, sustainable ATES requires the aquifer heat content to remain approximately constant while meeting heating and cooling demands and accounting for natural losses. Managing this complex system requires a good understanding of the aquifer, and good engineering practice. Performance can be optimized by storing heat/cool from other (sustainable) sources.
WP3 address these key science questions using numerical simulations and models based on the Sherwood aquifer across two length-scales: city-scale and single ATES project scale. The numerical modelling is used to investigate a range of storage scenarios beyond the field experiments conducted in WP2.
Modelling of ATES at the city-scale has a focus on Manchester, to investigate how multiple deployments may interfere and be optimised. Although Manchester has only one ATES deployment to date, understanding how ATES can be scaled-up to very large capacity is essential for future planning and to inform the policy and regulatory framework.
Aquifer geologic heterogeneity is known to impact on fluid flow and hence ATES capacity and efficiency. A range of different models representing different types and levels of heterogeneity are being optimized, to identify the range of storage capacity and efficiency, and which heterogeneities are key. Modelling is also used to address groundwater contamination and mixing. Coupled hydrogeological-thermal(-compositional) (HTC) simulations use ICL’s advanced open-source reservoir simulator IC-FERST, which uses dynamic unstructured mesh optimisation to allow high resolution simulations in a large or geologically complex model domain at lower cost than conventional fixed grids.
We are also developing a fully-coupled thermal-hydro-mechanical (THM) model using Comsol Multiphysics, to determine the geomechanical behaviour of the target aquifer under seasonal temperature and associated thermal stress variations. Cyclic injection/production operations will be modelled to evaluate the long-term geomechanical response of the subsurface fracture system, reservoir circulation and heat exchange performance over the operational life of ATES.
WP4: ATES system techno-economics, risks and decarbonisation potential
Key science questions: How to characterise, evaluate and optimise the techno-economic and environmental performance of different ATES site configurations? What is the decarbonisation potential of ATES? Does international benchmarking suggest favourable UK conditions, under which economic/policy framework? What share of UK’s geospatial heat demand can be met by ATES?
ATES systems require higher initial investment compared to conventional heating/cooling systems. Lack of quantitative assessment of the lifecycle value is a barrier to deployment. Moreover, ATES may not be considered because there is a lack of quantitative data demonstrating its life-cycle decarbonisation value.
WP4 consolidates a generic ATES site evaluation workflow, considering environmental and technical risks and operational constraints from WP3; studies potential operating patterns and revenue streams for UK ATES exemplars; develops robust techno-economic-environmental optimisation with tailored life cycle inventory models; quantifies the levelised cost of heating and cooling (LCOHC) and benchmarks against alternative technologies; assesses ATES performance at system level, given the UK’s future energy networks and market conditions.
WP5: Responsible ATES deployment in the UK
Key science question: How do we ensure that the deployment of ATES technology is socially desirable and undertaken in the public interest?
Negative views of subsurface operations in the UK have significantly increased in the wake of protests around exploitation of unconventional oil and gas resources. To avoid that for ATES, efforts should be made to ensure that society becomes a partner in co-constructing the path of innovation as opposed to seeking social acceptance in the final development phases.
WP5 advances the social desirability of ATES by developing and applying a Responsible Innovation (RI) plan based on the AREA framework (Anticipate, Reflect, Engage, Act). The RI plan builds on the lessons learned from a systematic review of policies, regulatory frameworks and community engagement strategies in support of ATES in Europe and OECD countries. The RI plan is being applied to a case study of the Greater Manchester Metropolitan area.
WP6: Integration and recommendations for policy and regulation
WP6 integrates across the technical data and model predictions, economic analysis and social science from WPs 1-5, providing translation to industrial and policy audiences. It delivers concise and accessible technical data and guidance to inform the regulatory frameworks and de-risk commercial implementation of ATES, and derives policy recommendations for local and national government to stimulate ATES deployment,