Category Archives: Heat

Techno-Economic-Environmental Analysis of A Smart Multi Energy Grid Utilising Geothermal Energy Storage For Meeting Heat Demand

Researchers based at Newcastle University from the EPSRC National Centre for Energy Systems Integration (CESI) and the Supergen Energy Networks Hub (SEN), Dr Seyed Hamid Reza Hosseini and Dr Adib Allahham, along with the Coal Authority, Dr Charlotte Adams, will soon publish their journal paper in IET Smart Grid.

About the author: Dr Adib Allahham

Dr Adib Allahham

Dr Adib Allahham is a Research Associate within the Power Systems Research Team, School of Engineering, Newcastle University and currently works on several projects including the EPSRC National Centre for Energy Systems Integration (CESI) and the Supergen Energy Networks Hub (SEN). Adib received his PhD from the University of Joseph Fourier in the field of control engineering. His research involves projects around the electricity distribution and off-grid power sector and multi-vector energy systems. These projects are addressing the need to cost-efficiently decarbonise the energy sector over the next thirty years by facilitating innovative network integration of new generation, and the integration of different energy vectors (electricity, gas, and heat). Computer simulation, laboratory investigation and demonstration projects are used together to produce new knowledge that delivers this requirement. He has published more than 25 technical papers in leading journals and conferences.

Contact details:
Profile details

About the paper

The UK Government has committed to a ‘Net Zero’ carbon economy by 2050 [1]. One major source of carbon emission is associated with heat demand from the domestic, commercial and industrial sectors.

Providing for heat demand accounts for around one third of UK carbon emissions [2]. In order to decarbonise the provision of heat, it is essential to increase the penetration of Low Carbon Energy Sources [1] in Smart Multi Energy Grids (SMEGs), i.e. integrated gas, electricity, and district heating and cooling networks [3,4]. This, consequently, has impact on the operation of SMEGs from the Techno-Economic-Environment (TEE) point of view [5,28].

Recent work on the geothermal potential of the UK’s flooded abandoned mining infrastructure has revealed a subsurface resource in place of 2.2 million GWh [11]. The impact of integrating this vast supply and storage potential on the operation and planning of SMEGs needs to be evaluated in terms of TEE aspects.

The paper identifies research gaps, including neglecting the electricity requirements of the components of the geothermal system that is required to boost the hot water quality and presents an evaluation framework for the Techno-Economic-Environmental (TEE) performance of Integrated Multi-Vector Energy Networks (IMVENs) including geothermal energy. Geothermal Energy Storage (GES), offers huge potential for both energy storage and supply and can play a critical role in decarbonising heat load of Smart Multi Energy Grids.

Schematic of SEH, GN & DHN
Fig.1 Schematic of the considered Smart Electricity Network (SEN), Gas Network (GN) and District Heating Network (DHN)

The two most common types of GES, i.e. High Temperature GES (HTGES) and Low Temperature GES (LTGES), were modelled and integrated within the framework which evaluates the impact of different low carbon energy sources including HTGES, LTGES, wind and PV on the amount of energy imported from upstream, operational costs and emissions of IMVENs to meet the heat load of a region.

Data from a real-world case study was used to compare the TEE performance of the considered IMVEN configurations for meeting the heat load. Data included wind and PV generation, as well as the heat and electricity load for a representative winter week of a small rural village in Scotland.

Fig. 2 The schematic of all the possible configurations of IMVEN considered in this paper

The results reveal that the most efficient, cost effective and least carbon intensive configurations for meeting the heat load of the case study are the configurations benefitting from HTGES, from a high penetration of heat pumps and from LTGES, respectively.


  1. [1] ‘Net Zero – The UK´s contribution to stopping global warming’,, accessed 20 December 2019
  2. [2] ‘Clean Growth – Transforming Heating: Overview of Current Evidence,, accessed 20 December 2019
  3. [3] Ceseña E.A.M., Mancarella P.: ‘Energy Systems Integration in Smart Districts: Robust Optimisation of Multi-Energy Flows in Integrated Electricity, Heat and Gas Networks’, IEEE Transactions on Smart Grid, 2019, 10, (1), pp. 1122-1131
  4. [4] Lund, H., Andersen, A.N., Østergaard, P.A., et al.: ‘From electricity smart grids to smart energy systems – A market operation based approach and understanding’, Energy, 42, (1), pp. 96-102
  5. [5] Hosseini, S.H.R., Allahham, A., Taylor, P.: ‘Techno-economic-environmental analysis of integrated operation of gas and electricity networks’. Proc. IEEE Int. Symposium on Circuits and Systems (ISCAS), Florence, Italy, May 2018, pp. 1–5
  6. [28] Hosseini, S.H.R., Allahham, A., Walker, S.L., et al.: ‘Optimal planning and operation of multi-vector energy networks: A systematic review’, Renewable and Sustainable Energy Reviews, 2020, 133, 110216
  7. [11] Adams, C., Monaghan, A., Gluyas, J.: ‘Mining for heat’, Geoscientist, 2019, 29, (4), pp. 10-15

Where is the value in cost, carbon and resilience in taking an energy systems integration approach to the UK’s energy future?

Researchers and Academics from the EPSRC funded Supergen Energy Networks Hub and the National Centre for Energy Systems Integration (CESI), Dr Adib Allahham, Dr Hamid Hosseini, Dr Vahid Vahidinasab, Dr Sara Walker & Professor Phil Taylor, recently published their journal paper in the International Journal of Electrical Power and Energy Systems on Techno-economic-environmental evaluation framework for integrated gas and electricity distribution networks considering impact of different storage configurations.

About the author: Dr Adib Allahham

Adib is a Research Associate within the Power Systems Research Team, School of Engineering, Newcastle University and currently works on several projects including the EPSRC National Centre for Energy Systems Integration (CESI) and the Supergen Energy Networks Hub.  Adib received his PhD from the University of Joseph Fourier in the field of control engineering. His research involves projects around the electricity distribution and off-grid power sector and multi-vector energy systems. These projects are addressing the need to cost efficiently decarbonise the energy sector over the next thirty years by facilitating innovative network integration of new generation, and the integration of different energy vectors (electricity, gas, and heat). Computer simulation, laboratory investigation and demonstration projects are used together to produce new knowledge that delivers this requirement. He has published more than 25 technical papers in leading journals and conferences.

Contact Details
email: @adiballhham

About the Paper

Governments around the world are working hard to reduce their Greenhouse Gas (GHG) emissions. In the UK, the government has set a target of “Net Zero” GHG emissions by 2050 in order to reduce contribution to global warming [1]. This necessitates the integration of more Renewable Energy Sources (RESs) into the energy networks and consequently reduction in the use of fossil fuels while meeting and reducing energy demand.

To achieve this objective flexibly and reliably, it may be necessary to couple the energy networks using several network coupling components such as gas turbine (GT), power-to-gas (P2G) and Combined Heat and Power (CHP) [2]. Also, the energy networks may benefit from different types of Energy Storage Systems (ESSs) in order to be able to compensate for any energy carrier deficit or other constraints in energy supply in any of the networks [3].

In order to comprehensively study multi-vector integrated energy systems and analyse ESS potentials, a Techno-Economic-Environmental (TEE) evaluation framework needs to be designed to investigate the mutual impacts of each of the networks on the operational, economic and environmental performance of others. This is the main aim of this study.

The paper divides ESS into two different categories of Single Vector Storage (SVS) and Vector Coupling Storage (VCS).

Figure 1: A conceptual representation of SVS and VCS storage devices in an Integrated Gas and Electricity Distribution Network (IGEDN)

A literature review looked at models which have been used to perform planning of the whole energy system of several countries taking into account all layers of the energy system, as well as different types of energy storage in multi-vector energy networks. As well as using a case study from a rural area in Scotland which is connected to the electricity distribution network only, also benefitting from a small wind farm and roof-top PV’s.

Fig. 2. The schematic of the studied rural area in Scotland including the separate gas and electricity networks (without considering P2G and VCS) and IGEDN (with considering P2G and VCS) [4]

A framework was developed as a result of the literature review carried out and this was tested on the real-world rural area in Scotland.  The evaluation framework provides the ability to perform TEE operational analysis of future scenarios of Integrated Gas and Electricity Distribution Networks (IGEDN).  Several specifications and achievements from this study are identified in the paper which is available to read online and will be published in the November issue of the Journal.

[1] Committee on Climate Change. Net Zero – The UKś contribution to stopping global warming, 2019. Google Scholar
[2] S. Clegg, P. MancarellaIntegrated electrical and gas network flexibility assessment in low-carbon multi-energy systems IEEE Trans Sustainable Energy, 7 (2) (2016), pp. 718-731 CrossRefView Record in ScopusGoogle Scholar
[3] S.H.R. Hosseini, A. Allahham, P. TaylorTechno-economic-environmental analysis of integrated operation of gas and electricity networks 2018 IEEE International Symposium on Circuits and Systems (ISCAS) (2018), pp. 1-5 CrossRefView Record in ScopusGoogle Scholar
[4] EPSRC National Centre for Energy Systems Integration (CESI)., 2017.

What will the UK’s future energy research and innovation infrastructure look like?

Dr Zoya Pourmirza and Dr Hamid Hosseini talk about their recent work as part of a team of energy experts from Newcastle University helping UK Research & Innovation with an analysis of the UK’s existing research landscape and future infrastructure requirements.

About the authors

Dr Zoya Pourmirza is a Research Associate in Newcastle University’s School of Engineering. She is involved in a number of research and teaching projects. Her principle research interests are in smart energy systems and information and communication technology (ICT) with particular emphasis on making the ICT infrastructure energy aware and cyber secure.

Contact details:
Profile details

Dr Hamid Hosseini is a Research Associate in Newcastle University’s School of engineering. His principle research interest is in the simulation and analysis of energy system. In his work for the EPSRC National Centre for Energy Systems Integration (CESI), Hamid has been investigating the planning, optimisation and operation analysis of integrated energy networks.

Contact details:
Profile details

UK Research & Innovation (UKRI) has recently published two reports giving an analysis of the UK’s existing research landscape and identifying its future infrastructure requirements. These reports make recommendations across six broad research sectors key to ensuring the UK remains a global leader. These six research sectors are Biological Sciences, Health and Food; Physical Sciences and Engineering; Social Sciences, Arts and Humanities; Environmental Sciences; Computational and e-infrastructure and Energy.

As members of a multi-disciplinary team of EPSRC National Centre for Energy Systems Integration (CESI) academics and researchers from Newcastle University, we were commissioned by UKRI to consult with the energy community. The team, led by CESI’s Director, Professor Phil Taylor, worked with UKRI to draft reports detailing our findings and recommendations. In carrying out this work, we made a substantial contribution to the preparation of the energy sections of the UKRI Research Landscape and Research Infrastructure reports.

Consultation exercise

The consultation exercise had three main aims: to inform future research and innovation infrastructure priorities, to provide the groundwork to ensure the UK remains a global leader in research and innovation and to set out the essential infrastructure needed to reach this long-term vision.

The team consulted extensively with leading UK energy industry and academics with expertise across a wide range of sectors, including nuclear, renewables, hydrogen, conventional technologies and whole energy systems. The consultation process was also extensive, including two questionnaires, four facilitated workshops at different locations across the UK and over one hundred 1-1 interviews with experts.

Initial analysis and findings

Based on the feedback received in the first stage of the consultation process, we drafted an interim report to UKRI giving an initial analysis of the UK Energy research infrastructure and a description of the existing energy research landscape. This interim report was included as a chapter in the UKRI Infrastructure Roadmap report alongside chapters for each of other five key research sectors.

An important finding of our initial consultation exercise was that opportunities to grow future energy research and innovation infrastructure could be classified in seven key themes. These informed further rounds of consultation, and are listed in the UKRI initial analysis report as follows:

  • Whole energy systems, including energy demand and power distribution networks
  • Fuel cells and hydrogen
  • Energy storage
  • Renewable energy sources
  • Alternative fuels
  • Nuclear energy – fission and fusion
  • Carbon capture and storage
Energy sector themes overview [Graphic: UKRI]

Final reports

Following this second consultation exercise, we incorporated our findings into two detailed reports for UKRI on the existing energy research and innovation landscape and on the sector’s future infrastructure requirements. These formed the basis of the Energy sections in the two recently published UKRI reports:

These reports referenced key energy research undertaken across the UK, including research involving multi-disciplinary teams from Newcastle University such as CESI and the Active Building Centre (ABC).

Key findings and recommendations

As a result of the consultation exercise, we helped to develop a snapshot view of existing infrastructure of regional, national and international importance. We identified thirty-three dedicated energy infrastructures and help to write case studies of existing key energy research infrastructure which were published in the Landscape Analysis report.

In the report identifying opportunities to grow our capacity, our findings contributed to recommendations for how the energy themes can be progressed and identifying case studies for each. The published case studies include one of CESI’s research demonstrators, The Integrated Transport Electricity Gas Research Laboratory (InTEGReL), as infrastructure offering a whole-systems approach to the UK’s energy use. Newcastle University is working in partnership with Northern Gas Networks and Northern Powergrid to develop the site. Its aim will be to allow academia, industry and government to explore and test new technologies in the electricity, gas and transport sectors in one place, delivering a more secure, affordable, low-carbon energy system.

The Integrated Transport Electricity Gas Research Laboratory (InTEGReL) [Graphic:Northern Gas Networks]

Of particular relevance to CESI are the recommendations for the whole energy systems theme. These include a new interdisciplinary centre for excellence in energy analysis integration and a decarbonisation of heat demonstrator, both of which will make an important contribution to investigations into how we might achieve a net-zero energy future.

UKRI Research and Innovation Infrastructure: Energy
Project team

Professor Phil Taylor
Dr Damian Giaouris
Dr Sara Walker
Dr Zoya Pourmirza
Dr Hamid Hosseini
Laura Brown
Alison Norton

Getting it done? The UK 2020 Budget and the support for a net-zero transition in the energy sector.

About the authors:

Dr Sara Walker is Reader in Energy at Newcastle University and Director of Newcastle University Centre for Energy.

Professor David Flynn is Professor of Smart Systems at Heriot Watt University

Both Sara and David are Associate Directors of the EPSRC National Centre for Energy Systems Integration, a £20m collaborative research programme with industry and government investigating the social, ecconomic and technical value in energy systems integration.

March 2020 Budget

On 11th March 2020, the Chancellor Rishi Sunak presented to Parliament the Government budget¹. This was an opportunity for the UK Government to clearly signal its commitment to deliver on the net-zero greenhouse gas emissions target for 2050 and to also lay the groundwork for COP26 as the host nation.

Albeit the language of the previous administration associated with “industrial strategy” was dropped, the Government retained a reference to the Grand Challenges, indicating that there is likely to be continued investment into energy innovation and climate change mitigation. A key indication of this is the commitment to at least double investment in the Energy Innovation Programme.


The first mention of issues related to energy in the Chancellor’s speech came with an announcement to continue the freeze on fuel duty. For comment on this, and other transport initiatives in the Budget, we refer you to DecarboN8’s review². In a separate announcement, Business Secretary Alok Sharma previously confirmed a £36.7 million investment to design, test and manufacture electric machines. £30 million will be used to create a national network cutting-edge centers led from Newcastle University – based in Newport, Nottingham, Strathclyde, and Sunderland – to research and develop green electric machines including planes, ships, and cars. This represents the “demonstrator” element of the Industrial Strategy Challenge Fund Driving the Electric Revolution Challenge.

And then …

The second mention of energy came in an announcement, as part of the Research and Development (R&D) spend, of £900m funding for nuclear fusion, space, and electric vehicles. As employees of research organizations, we welcome the announcement of £22bn per year by 2024-25, in research and development. However, the role of new nuclear in the Committee on Climate Change Net Zero technical report³ is relatively minor.
On housing, the Budget refers to £12.2bn for the Affordable Homes Programme over 5 years, a push for 300,000 new homes per year, and reforms to planning to accelerate development. No commitment is made to the standard of new homesª, or retrofit of existing homes, which is inconsistent with the Committee on Climate Change Net Zero report, which found that high levels of energy efficiency are needed to get close to the zero targets.

What does this mean for energy sector? 

There is a clear need to improve the quality of UK homes, in a way that reduces energy use and moves us towards heating systems that use lower-carbon fuels. We need to make urgent changes in this area, from research to improve the performance of individual technology like heat pumps, to understanding possible future housing performance and the energy needs associated with that. The EPSRC National Centre for Energy Systems Integration (CESI) is looking at these types of research challenges.

The meat of the Budget from an energy perspective is in the Budget report section on “Growing a greener economy”. There is an announcement to double the size of the Energy Innovation Programme as mentioned previously, although some of this money is for R&D and therefore likely to be included in the figures above. A further £800m was announced by the Chancellor for the development of two Carbon Capture and Storage (CCS) sites through the creation of a CCS Infrastructure Fund. CCS support was removed by previous administrations but is integral to many scenarios within the Committee on Climate Change Net Zero report.

No figures are mentioned, but the Budget report includes a new support scheme for biomethane funded by a Green Gas Levy, and a Low Carbon Heat Support Scheme to enable the installation of biomass boilers and heat pumps. £270m is promised to enable new and existing heat networks to adopt low carbon heat sources, to follow on from funding of £97m for the final year of the Heat Networks Investment Project (HNIP). There is a rise in the Climate Change Levy on gas (for 2022-23 and 2023-24). The Renewable Heat Incentive is extended to 31st March 2022. Furthermore, £10m in 2020-21 is to support the design and delivery of net zero policies and programs. Heat networks are an area of research for the EPSRC National Centre for Energy Systems Integration (CESI), and we also expect to investigate more scenarios with hydrogen and CCS now that the goal for the UK has changed from 80% to a net-zero target.

And Finally

Given the critical interdependencies of our energy infrastructure to other vital services e.g. water, transport, services from public buildings, we also see opportunities to accelerate and distribute the efforts in decarbonisation by utilising the opportunities of the Making the most of Government knowledge assets initiative. The public sector holds around £150 billion of knowledge assets (intellectual property, tech, data, etc.), which is vital in shaping the operation and planning of decarbonised services. However, the absence of any Budget support for solar, wind, and storage – elements seen as vital with renewable generation four times current levels in some Committee on Climate Change scenarios – is of great concern. As is the lack of investment to decarbonise the building stock.

Getting it done isn’t the same as getting it right. And for the UK energy sector, there is very little in the budget which gives confidence that we are doing enough, let alone doing it well.


  2. with for example: £403m for the Plug-In Car Grant; £129.5m to extend the scheme to vans, taxis and motorcycles; Vehicle Excise Duty exemption; £500m over 5 years to roll out rapid charging; removing red diesel tax relief; £304m for NOx reduction; freeze of fuel duty; £20m midlands rail hub; £5bn for new buses and cycling; £500m pothole fund; all dwarfed by the £27bn between 2020 and 2025 for road investment. Aviation is also mentioned with regards regional connectivity.

ª “2.95 Future Homes Standard – The government is committed to reducing emissions from homes and to helping keep household energy costs low now and in the future. In due course, the government will announce plans to improve the standards of new built homes.”

The Future of Energy – Dr David Greenwood

Dr David Greenwood discusses talks delivered at a recent Cafe Scientifique event by three CESI researchers on their vision for the future of energy .

About the author:

Dr David Greenwood is a researcher with the National Centre for Energy Systems Integration (CESI) and is based at Newcastle University.

His research focuses on taking advantage of flexibility within energy systems and understanding sources of uncertainty and variability such as customer demand and intermittent generation.

Contact details:        Profile details

Inspired by the Great Exhibition of the North, Newcastle University hosted a series of Café Scientifique events at the Urban Sciences Building, part of the rapidly expanding Newcastle Helix site.

The National Centre for Energy Systems Integration organised one of these events, with the title “The Future of Energy”, where three CESI researchers presented the vision of the UK’s energy future, and how we can get there.

Cafe Scientifique:  The Future of Energy  at Newcastle University’s Urban Sciences Building

Dr David Jenkins – who had travelled from Heriot-Watt University for the event – gave his thoughts from the perspective of energy demand, how it could change it, and how we could meet it. Dr Jenkins talked about the data challenges in modelling energy demand. This includes the temporal and spatial scale of the available data, and the effects of aggregating large numbers of energy users, which generally works in a modeller’s favour by giving a smoother, more predictable pattern of demand. The impact of a number of low-carbon technologies, such as electric vehicles and heat pumps, which are vital if heat and transport are to be decarbonised by moving them onto the electricity system, was examined, with the summation of these changes resulting in the potential for a substantially different demand pattern to that experienced today.

Figure 1: The potential difference between present and possible future energy demand

Next, Dr David Greenwood spoke about the need for flexibility within the energy system, and the challenges in procuring it through the markets and mechanisms that are currently used by the energy industry and in particular the electricity system operators. Dr Greenwood’s main argument was that we need flexibility – which already exists on the system in many forms – to address uncertainty on a variety of timescales ranging from when a customer plugs in their electric car, to how quickly and substantially low carbon technologies are adopted, to when new power stations are completed, all with the possibility of a failure anywhere in the system at any time. He concluded by presenting a flexibility case study based around energy storage, and showing how uncertainty and flexibility can be included within operational decision making processes.

The final presentation of the evening was given by Dr Andrew Jenkins, and had a focus on the whole energy system. Dr Jenkins talked about how the whole energy system can deliver cross-sector flexibility while still fulfilling the needs of its customers. He demonstrated this with a case study on electric vehicles using Vehicle to Grid charging technology, which could meet a set of system requirements whilst ensuring that their drivers would have enough energy to complete their journeys at the end of the day. He concluded with a detailed description of the university’s new InTEGReL site – a joint venture with Northern Powergrid and Northern Gas Networks which will showcase the potential for heat, transport, gas, and electricity to operate synergistically, providing cross-vector energy flexibility, and allowing validation of models and theory arising from academic research.

Figure 2: An overview of the InTEGReL site

The evening ended with a discussion with the audience – a range of attendees; consumers, prosumers, consultants, academics – which broadened the debate to include the political landscape, and more input from the perspective of the energy consumer. The audience had a breadth of technical knowledge, and their questions reflected this. Electric vehicles – which link the electricity and transport sectors – were the most popular topic for discussion, but the potential of power to gas, sources of inertia in zero-carbon energy systems, and the impact of energy efficient homes were also discussed. The event ended by a resounding agreement from the audience that they would like to attend another event on the topic of energy.

If you would like to suggest a topic for a future event, please get in touch at

Keeping warm: deep geothermal potential of the UK – Professor Jon Gluyas and Dr Charlotte Adams

Jon Gluyas and Charlotte Adams discuss  recent CESI research which looks at how the UK’s heat supply can be decarbonized and national energy security improved.

About the authors

Dr Charlotte Adams is Assistant Professor in the Department of Geography at Durham University and a Mid Career fellow in the Durham Energy Institute.  She is Manager of BritGeothermal, a UK-based consortium focusing on deep geothermal research both in the UK and internationally.

Contact:      Profile Details



Professor Jon Gluyas is an Associate Director of CESI,
Executive Director of Durham Energy Institute and
holds the ØRSTED/IKON Chair in Geoenergy, Carbon Capture & Storage in the Department of Earth Sciences at Durham University.  Jon has published widely, including text books, memoirs and over 100 per review papers

Contact:      Profile Details

Two recent papers to emerge from CESI examine the potential to decarbonize the UK’s heat supply and simultaneously improve national energy security. It is likely that most will view improvement of UK energy security as the priority given threats to UK gas supplies resulting from the diplomatic fall out between the UK and Russia. The link between gas supply and heat is straightforward.

About half the UK’s energy consumption is used to generate heat for domestic, commercial and industrial spaces and burning natural gas generates most of that heat. Since 2005 the UK has been progressively more dependent upon gas imports to meet demand. Currently, we can supply around 35-40% of our needs with about the same coming from Norway via the Langeled Pipeline. Much of the remainder is supplied as LNG from Qatar leaving about 5% that comes via the interconnectors from Belgium and the Netherlands. No single molecule of methane travels from Moscow to London but that 5% from Europe is essentially controlled by Russia because of its dominance on the European gas supply market. To exacerbate the situation, the UK has but a few days gas storage supply, mostly though changing the pressure in the nationwide gas network. This compares very unfavourably with both Germany and France both of which have about 3 months stored supply.

Gas supply warnings, though infrequent, demonstrate how precarious the situation is. The most recent was issued on 1st March 2018 amid the icy conditions of a late-winter cold snap. Others have accompanied similarly freezing weather in 2010 and problems with the Langeled Pipeline in 2009. The ongoing tiff between Qatar and Saudi Arabia has not yet had an impact on supplies of LNG but it could. National Grid was able to withdraw its warning after about 24 hours but it remains highly likely that UK gas and hence heating supplies could be interrupted by either political or technical issues. We are vulnerable!

The two papers referred to at the start of this article lay out the resource potential of low enthalpy geothermal heat in the UK. The article by Gluyas et al on ‘Keeping warm: a review of deep geothermal potential of the UK’ examines how much heat could be extracted from sedimentary basins and granite bodies while Adams and Gluyas article on ‘We could use old coal mines to decarbonize heat – here’s how’ looked at the resource potential of ultra-low enthalpy heat in abandoned flooded coal mines. A very conservative estimation indicates that at current levels of heat use there is an absolute minimum of 100 years heat supply from these sources. Moreover, such heat sources have a near zero carbon footprint.