The IEA CCC has produced reports on UCG (underground coal gasification) in the past, the most noted of which is the 2009 report from Gordon Couch. Some further developments have been made in the industry since Gordon’s review was published and so the CCC is keeping a watching brief on the issue.
This CRF meeting was a healthy mix of regulators, industry, academia and commercial companies. I gave a general overview of where UCG could fit in the energy mix as a potential HELE (high efficiency low emissions technology) which would allow coal to continue to be a valuable energy source in a low-carbon future. This was to set the scene for the more technical papers to follow. Hopefully these will be made available on the CRF website (www.coalresearchforum.org) in due course as the quality of the papers was exceptional.
The majority of information I presented was based on Gordon’s 2009 report which is still regarded as the UCG “bible”.
Michael Green, UCG Engineering Ltd, (a bit of a legend in the UCG industry) gave an excellent, comprehensive review of UCG development in the past and projects which are ongoing. Mike covered the historical studies from the early Russian work in the 1940s up to current commercial developments, explaining the different challenges faced by each. Many projects were discontinued due to physical challenges such as the depth or characteristics of the coal and the relative inexperience with the technology. Others closed simply due to the economics, with the drop in natural gas prices making some US projects no longer financially viable.
Currently there are activities ongoing in Europe with the EU funding the HUGE project at the Barbara mine in Poland as well as the TOPS project in Bulgaria, the latter aiming to combine UCG with CCS. BHP is currently a co-funder of the new Africary project in South Africa and Shemna Industries in China is claiming success with the SinoCoking Ltd syngas project. Mike seemed somewhat sceptical at the quantity of gas which the SinoCoking claim to have produced since the project started. Mike then closed by expressing enthusiasm for the new UCG projects being developed by CNR and 5Quarters in the UK and with a handy list of what he regarded as the current leading UCG projects:
– Linc Energy in Wyoming, USA
– Carbon Energy in Queensland, Australia
– SinoCoking in China
– KHW in Poland
– Eskom (Majuba) in South Africa
– ENN in China
– Yerotzigas in Uzbekistan
Dermot Roddy of 5Quarters in the UK focussed on UCG prospects in the UK highlighting the fact that the UK has incredible coal resources of which it has used only a tiny fraction. Dermot gave an overview of the challenges faced by a company trying to move UCG into commercialisation in a country such as the UK – technical, economic and legislative. UCG has the potential to feed chemicals into industrial feedstock at a commercially advantageous rate. For example, in the US, shale gas is feeding syngas into the ethanol market at 1/6 of the price of Asian sources. The issue of PR and public perception was also covered – “expect more intense questioning at a larger scale”. The public asks questions about greenhouse gas emissions and will want to know, at the start of any new fossil fuel project, where the CO2 is going to end up and are starting to care more about full life-cycle analysis of the whole process rather than just the question of how much of the produced CO2 is captured. More details of the 5Quarters work can be accessed at www.five-quarter.com
Tom Smyth of BIS (Business, Innovation and Skill at the UK Government) gave an honest appraisal of the current UK government stance on coal. The remaining three coal mines in the UK will close by the end of 2017 and there are no plans for any future deep mining in the UK. A few opencast mines are still operational. The UK chemical industry, on the other hand, is healthy and growing. Priorities for the UK are largely on securing competitive energy and feed stocks. This includes:
– Support for exploitation of unconventional gas, biofuels and waste
– Assistance in the demonstration of the commercial viability of shale gas by 2014 for commercial flows by 2017
– Support for CCS
The UK chemicals industry could increase turnover by an order of magnitude by 2030 and unconventional gas, including UCG, would be an integral part of this growth.
Ken Ferguson, now retired, but previously head of the UK Coal Authority, gave an expert consideration of UCG versus shale gas. Ken raised the very important point that the much of the UK public put UCG and shale gas into the same pigeon-hole and, as a consequence, regard both very negatively whilst, in fact, they are “as different as chalk and cheese”.
Ken provided a very neat list of the comparative costs of energy in the UK:
– Offshore wind £140-170/MWh
– Onshore wind £80-100/MWh
– Clean coal combustion £110/MWh (with CCS)
– Nuclear (Hinkley point, predicted) £93/MWh
– IGCC coal £110/MWh (with CCS)
– Existing CCGT £60-100/MWh
– New CCGT with CCS £90-110/MWh
– UCG and CCS £70/MWh
(capture cost estimated at $14/t CO2; $30/t carbon)
With the current UK bulk power costs at £40-60/MWh, UCG with CCS is the only option which even approaches this.
Comparing shale gas and UCG is complex. Shale gas is marketable as conventional natural gas where as UCG gas is not – UCG produces raw syngas (about 1/2 the calorific value of shale gas, after CO2 scrubbing, 1/3 without scrubbing). The cost of flue gas CO2 scrubbing from shale gas would be five times greater than that for UCG. So, although shale gas in the UK is predicted to cost around the same as natural gas, once CCS becomes necessary on gas plants, the cost of CCS on shale will be significantly more than that on UCG.
Ken stressed that perhaps the most important difference between shale gas and UCG is the environmental considerations. Unlike shale gas, UCG requires the strata and groundwater to be undisturbed and gas-tight. UCG does NOT entail fracturing, water pumping or pumped chemicals – three of the major problems which cause the public negativity towards shale gas. The area of land utilised by UCG is also significantly smaller than that for shale gas.
Ken then closed by announcing that the UCG Association was petitioned for dissolution in March 2015, which would explain why Julie Lauder was absent despite her being listed on the agenda as a speaker. This dissolution was more than likely as a result of the nature of the industry – with many projects moving to the development stage but protected by commercial secrecy, the association was unable to act as the information sharing and dissemination forum that it was intended to be, which is unfortunate.
The afternoon started with a technical presentation by Yong Sheng, a student at Leeds University. Yong’s work focussed on the use of a model to predict the cavity growth during UCG at the new project in Bulgaria. Using 3D positioning of faults within the seam in relation to the local environment, and taking into account the permeability of the coal and surrounding strata, the model suggested that gasification should be limited to areas which are at least 150 m away from any faulting to ensure that contamination to local aquifers is completely avoided. A second project used the model to consider the CO2 storage capacity at the site and in surrounding seams. The model is in developmental stage and Yong emphasised that such modelling techniques are in their relative infancy. Another student, Juan Alvarez-Vazquez of Glasgow University, then gave an overview of his thesis work on thermo-chemical modelling and UCG, which takes into account chemical and physical transformations as well as cavity growth. His model neatly showed the movement of heat, char and gas profiles through a theoretical coal seam over a specified time period. At this stage, the model is arguably crude but still impressive considering the huge chemical mathematical complexity of the model and the limited practical data available.
Vasilis Sarhosis, University of Wales, introduced the SEREN (Sustainable Earth Energy) project. The project is supported by the BGS (British Geological Survey) as well as several Welsh Universities and some local industry partners. The project focusses on making Wales self-sufficient in terms of energy and is looking mainly at UCG, CCS on coal and ground source heat. The two coal fields in Wales have been shown to contain the potential for UCG – 220 Mt of usable reserves amounting to 40 years’ worth of energy for the region. At this stage the UCG sector of the project is looking at evaluating the potential for development as well as considering the environmental issues which are relevant to the region. Not all of the coalfields in Wales have been characterised in enough detail to predict potential UCG applicability. Further challenges include public acceptance (the Welsh population have been relatively vocal in their response to proposed fracking) as well as establishing the legal framework for UCG projects under national and regional regulations. The universities are supporting the project with the production of models and assessment toolkits. Exploratory drill hole work has commenced at several sites in the south of Wales to help characterise the coal and also to evaluate the quality of water in the region. A semi-commercial trial in a 600×600 coal block is planned as part of the EU MEGA project.
Finally Ben Roullier, University of Nottingham, looked at the environmental impact of UCG and gave a description of the model being developed to look at surface subsidence, groundwater pollution and groundwater depletion simultaneously at UCG size. The model combines two areas – mechanical and fluid parameters are considered together. Plans are underway to expand the model to consider the transfer/diffusion of contaminants within the seam and associated waters.
Overall this was an excellent meeting, the question and answer sessions reflecting the excitement in the fossil fuel community for the perceived move forward towards commercialisation of UCG along with a frustration that we are still not there yet. UCG has the potential to fit neatly into a HELE (high efficiency low emission) future, but to do so it must do more to prove itself to a keen but perhaps still somewhat hesitant energy sector.