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Publication - Report

Independent Review of Underground Coal Gasification - Report

Published: 6 Oct 2016
Part of:
Business, industry and innovation

An independent examination of the issues and evidence surrounding Underground Coal Gasification.

239 page PDF


239 page PDF


Independent Review of Underground Coal Gasification - Report
8. Climate

239 page PDF


8. Climate

8.0 Climate issues set a key part of the global context for UCG as well as framing the connection between GHGs generally and the local emissions and products of the process. Inputs to this chapter come from the academic literature, academic interviewees, the CCC and informed commentators.

8.1 This report does not, and cannot, seek to provide an overview of global and European climate science or even of the UK climate and carbon position in any detail. Contextual reports and assessments can be found in the work of the Intergovernmental Panel on Climate Change ( IPCC), in Hansen et al (2013), and an instructive paper by McGlade and Ekins (2015).

8.2 UCG processes are predicated on the partial conversion and effective oxidation of carbon in the coal, with addition of air or oxygen and steam, to methane. Combustion with oxygen produces "product gas" which is methane, with associated carbon dioxide, CO 2, carbon monoxide, CO and hydrogen ( H 2) as well as combustion products derived from the impurities in the coal. Combustion with air, adds significant nitrogen to the gas product mix. From the point of the release of these gases, through their transmission to the surface and during their subsequent processing, separation and distribution, they can and will be released to the atmosphere. Some of this is intended through its use (methane for gas supply and industrial use for example will be released post secondary combustion or processing if not locked into new chemistries/products), results from flaring or "controlled" releases and some will be fugitive (leaks) and/or as a result of incidents of loss of control. These gases if not locked into new materials or stores for the long term, will contribute to the greenhouse gas ( GHG) load of the atmosphere which is in turn causing climate change effects.

8.3 The whole picture of the stocks and flows of carbon on the Earth, while well understood generally, is not fully understood at a detailed and localised level. The many components of the geology and soils beneath us, the oceans around us, the biosphere of the planet and the human communities living within this context as well as the atmosphere around and over it, are still being studied. The subject in itself is an area of emergent science, with many elements not yet fully understood or quantified. Understanding the exchanges over time between the various parts of the system is complex. Gas use and market development sit in that context. Understanding the scale, significance, inputs and impacts, of individual industries, such as UCG, and the processes involved is often problematic and uncertain, compounded by data availability.

8.4 Fugitive impacts in particular are hard to assess when we have rarely measured what is emergent from the soil and surface water bodies, former mines and other possible sources and hence contextualizing new extraction is challenging. Also, as will be touched on in the energy policy chapter, much depends on whether UCG gas would substitute for other gas. An arguable advantage of UCG methane and hydrogen could be their local production and hence availability and their local use, both potentially stimulating new markets, serving existing ones and minimising transport impacts and use of imports. What happens to the carbon dioxide remains a key question.

8.5 On top of these factors, is added the nature of UCG gas - the main elements and mixtures were addressed in the Geology and Technology chapters earlier and some results shared suggest the gas produced is more complex or "dirty" than gas sourced from some reservoirs in the North Sea. This means subsequent processing, cleaning, would be required with extra energy inputs to ensure separation into purer usable ingredients. This technology is well-developed and deployable. Overall the impact the gas has will be determined by its composition, the volumes generated and how it is used.

8.6 The UK Committee on Climate Change ( CCC) has not offered an opinion on UCG specifically but has regularly provided a view on climate change issues for the UK as a whole, as well as a commentary for Scotland, as part of UK and devolved administration climate policy implementation, carbon budget and target reporting arrangements.

8.7 CCC Report 2016

"Shale gas exploitation by fracking on a significant scale is not compatible with the UK's climate change targets unless three key tests are met - on methane leaks, gas consumption and carbon budgets." This was the headline result of the July 7 2016 Report of the CCC on onshore petroleum in conjunction with their latest carbon budget. Whilst dealing with onshore gas, in the UK context and given its remit, the CCC's findings are relevant because they frame the production of gas in a climate change setting that is just as relevant to UCG.

8.8 The CCC website expands, "The Committee's report 'The compatibility of UK onshore petroleum with meeting the UK's carbon budgets' is the result of a new duty under the Infrastructure Act 2015. This duty requires the CCC to advise the UK Secretary of State for Energy and Climate Change about the implications of exploitation of onshore petroleum, including shale gas, for meeting UK carbon budgets."

8.9 The CCC's report finds that the implications of UK shale gas exploitation for greenhouse gas emissions are subject to considerable uncertainty - from the size of any future industry to the potential emissions footprint of shale gas production. It also finds that exploitation of shale gas on a significant scale is not compatible with UK carbon budgets, or the 2050 commitment to reduce emissions by at least 80%, unless three tests are satisfied:

8.9.1 "Emissions must be strictly limited during shale gas development, production and well decommissioning. This requires tight regulation, close monitoring of emissions, and rapid action to address methane leaks.
8.9.2 Overall gas consumption must remain in line with UK carbon budgets. The production of UK shale gas must displace imports, rather than increase gas consumption.
8.9.3 Emissions from shale gas production must be accommodated within UK carbon budgets. Emissions from shale exploitation will need to be offset by emissions reductions in other areas of the economy to ensure UK carbon budgets are met.

8.10 "At this early stage, it is not possible to know whether the tests will be met easily or not. The Committee will closely monitor steps taken by Government and other relevant agencies to satisfy these tests. The Committee will report publicly on performance against the tests. In addition, the Committee will assess the Government's forthcoming Emissions Reduction Plan - which will set out how the Government will meet the fourth and fifth carbon budgets - in light of the possible development of a UK shale gas industry."

8.11 Professor Jim Skea, a member of the Committee on Climate Change, said:

"Under best practice, UK shale gas may have a lower carbon footprint than much of the gas that we import. However, gas is a fossil fuel wherever it comes from and is not a low-carbon option, unless combined with carbon capture and storage. This report sets out the tests that must be met for shale gas development to be consistent with UK carbon budgets. Existing uncertainties over the nature of the exploitable shale gas resource and the potential size of a UK industry make it impossible to know how difficult it will be to meet the tests. Clarification of the regulation of the sector will also be needed. The Committee on Climate Change will provide ongoing, independent assessment of whether these tests are being met."'

8.12 Professor Skea was also interviewed for this study, tapping into his climate and energy expertise as well as his CCC role. See Annex 2.

8.13 The CCC has produced a Scottish emissions picture, a 2015 progress report as well as views of the trajectory to 2030 and "the high ambition pathway towards a low-carbon economy" are all accessible on the CCC website. These do not particularly address UCG.

8.14 Bond et al (2014) undertook a life-cycle assessment ( LCA) of GHG emissions from unconventional gas in Scotland. The study responded to SEPA's observations in 2012 ( SEPA, 2012) that "there is a lack of real field data (on greenhouse gas emissions)" and noted that, "different assertions exist as to the extent of fugitive emissions of methane during shale gas operations compared, for example, to conventional gas extraction. Until this dispute is resolved by collection and analysis of actual data SEPA will remain neutral but requires operators to make full use of technologies that capture the gas prior to escape in order to reduce fugitive methane emissions."

8.15 Whilst this work focussed on Shale Gas and CBM, both the principle of collection of, and accounting for, fugitive methane as well as the overall approach to and review of direct and indirect GHG dimensions of unconventional gas activities are extremely useful.

8.16 Addressing UCG specifically, FoES, WWF and RSPB as well as the Broad Alliance, all interviewed for this review, also raised the issue of the principle of compatibility of UCG and GHG production. They also raised the risks of leaks and fugitive emissions generally from this, further proposed generation and release of GHGs and its poor fit with Scotland's existing climate commitments and approach to decarbonisation of the economy generally. Permitting UCG was seen as wholly incompatible and contradictory.

8.17 Estimates of gas production are very hard to find and crude assessments are the best that can be done, but the context is extremely clear and well known. As introduced above, Hansen et al (2013), McGlade and Ekins (2015) and the work of the Intergovernmental Panel on Climate Change ( IPCC) generally set the scene globally and lead to a general conclusion that a strong case can be made for not progressing with further generation of atmospheric CO 2 and methane given their known impacts and the budgets of these gases remaining if damaging impacts are to be minimised or avoided.

8.18 Hansen et al (2013) provide an analysis that suggests existing, conventional coal resources amount to c.860Bt. A further 1600Bt CO 2 could be produced from new/unconventional exploitation methods, including UCG, Coal Bed Methane ( CBM) etc. If all existing conventional reserves were burned this would contribute c.500Gt of carbon emissions, essentially the equivalent of the whole planetary carbon budget since the start of the industrial revolution. [This is c 370 Gt C by 2013 and c 130Gt left - 477Gt of CO 2. An additional c100Gt C exists locked for now in the biosphere.] Their estimate of only 130Gt would remain before breaching a 1.5°C threshold is salutary. Emissions therefore need to be limited to a maximum of 656 Gt CO 2 for 2007-49 based on the assumptions made. This analysis appears broadly supported. Budgets can be constructed on that basis.

8.19 In the Scottish context, the CCC (2016) reports describe the progress already made in Scotland in terms of carbon reductions and Bond et al (2014) attempt to describe the place of UGE in that context. At best, impacts are uncertain. The Belltree Group (2014) Kincardine Feasibility Study, which looked at the resource in that one licence block, one of the two still "in play" in the FoF, the mid-range estimate of accessible coal was 43Mt, the rough equivalent, if all gasified and used for electricity generation, of 120Mt of CO 2. That is around three times the total of Scottish emissions or roughly 18 years of the equivalent prior operation of Longannet. Whilst the full exploitation of this resource under demonstration or operational panels may be unlikely, especially in the short to medium term, it gives a sense of the potential impact.

8.20 FoES suggested that it would be "absolutely irresponsible" to pursue a new source of fossil fuels or access high carbon coal reserves previously inaccessible and a "huge distraction" from the necessary decarbonisation mission. They also highlighted issues of fairness and equity in relation to developing nations and particularly low-lying countries worldwide. ( )

8.21 In interview, FoE also critically observed that, given the timetable likely to apply to getting a demonstration facility operational and progressing to full scale operations, including planning and other processes entailed, it was in their view unlikely that such an operation would be able to be in place within 10-15 years, by which time the Scottish economy would need to be wholly decarbonised. "It therefore simply doesn't stack up. UCG has no place."

8.22 Pfeiffer et al's (2016) analysis also highlights the dangers of lock in and stranding of assets if the zero carbon targets necessary (post c.2017 if the carbon budget ceiling has already been reached, following the IPCC AR5 pathway), are taken seriously in future.

8.23 Bond et al's (2014) work is unusual in that it took a life-cycle approach and it concluded that methane and other GHG emissions could occur during drilling and production and from fugitive sources but that emissions per unit of energy generated by UGE are "likely to be equivalent to those from conventional gas extraction in Europe if best practice is followed" and peat soils/habitats are avoided.

8.24 Gas from controlled processes as well as fugitive emissions are generally assumed by industry, although data are very hard to obtain, especially for the latter. Releases by regulated facilities would be expected to be included in licence terms, compliance reports and in national gas inventories under UK (and currently EU), US and Australian law, for example. When asked, Australian commentators observed that GHG impacts and actual releases, especially fugitive losses were not generally considered a priority. As in the EU model, in Australia, total emissions reporting would be undertaken and would connect local regulated emissions to that total. At this point, data on gas total emissions are not widely available, shared or used.

8.25 Carbon capture and storage ( CCS) or other effective sequestration methods to offset carbon emissions were discussed with most interviewees. Profs. Haszeldene, Russell, Shipton, Skea and Younger all observed that deployment of carbon capture technology would radically affect the approach taken to the emissions of all UGE including UCG. None of those interviewed considered there to be any realistic prospect now or for the foreseeable future of a CCS investment being made and particularly at a scale and with a timetable likely to allow a neutral trajectory to be achieved, with current emissions or in the context of UGE. No other sequestration method appears likely to make a relevant contribution in this context and in the shorter term.

8.26 Summary

Climate change and decarbonisation targets would be very seriously impacted by unmitigated releases of UCG GHGs if operated at scale, making the achievement of current or stronger commitments much more difficult if not impossible. Without CCS or similar sequestration or storage options in place, while demonstration plant might have a minor impact in the longer term, full scale operation exploiting the scale of the resource available would be potentially very damaging both in fact and reputationally. Thus, even given the uncertainties around substitution or actual levels of final emissions, controlled or fugitive, it is very hard to conclude that UCG is viable in carbon budget or climate change terms. With CCS, fixed in long term reservoirs or fixed in new materials or wholly offsetting imports, the impact would be less unfavourable.


Belltree/ CNRL (2014) UCG Potential of CNR's Kincardine Licence, Firth of Forth, Scotland. Berrow et al.

Bond C.E., Roberts J., Hastings A., Shipton Z.K., João E.M., Tabyldy Kyzy J., Stephenson M. (2014) Life-cycle assessment of greenhouse gas emissions from unconventional gas in Scotland. A ClimateXChange Report, Scotland,

See also from ClimateXChange - UGE in Scotland: an update for policy makers, planners and regulators

CCC (2016) Meeting Carbon Budgets - 2016 Progress Report to Parliament

FoEI (2016) Fuelling the Fire: the chequered history of Underground Coal Gasification and Coal Chemicals around the world.

See also

Hansen J, Kharecha P, Sato M, Masson-Delmotte V, Ackerman F, Beerling DJ, et al. (2013) Assessing "Dangerous Climate Change": Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature. PLoS ONE 8(12): e81648. doi:10.1371/journal.pone.0081648

McGlade, C and Ekins, P (2015) The geographical distribution of fossil fuels unused when limiting global warming to 2°C. Nature, vol. 517, no. 7533, 2015, pp. 187-190

Pfeiffer, A. Millar, R., Hepburn, C., Beinhocker, E. (2016) The 2 oC capital stock for electricity generation: committed cumulative carbon emissions from the electricity generation sector and the transition to the green economy. Applied Energy 179 October 2016, 1395-1408

SEPA (2012) Regulatory guidance: Coal bed methane and shale gas.