Fossil fuels: more than we can safely burn

Martin Quick CEng discusses concerns about tar sands and shale gas in relation to the drastic reductions in fossil fuel use shown to be needed in the latest IPCC report.

Extended version of an article from SGR Newsletter no.42; published online: 13 January 2014

The publication of the latest report of the Intergovernmental Panel on Climate Change (1) reinforces the case that drastic and rapid reductions in global greenhouse gas emissions are needed to reduce the risk of dangerous climate change. The report quantifies the allowable carbon emissions for a range of probabilities of exceeding 2°C temperature rise. This is the rise generally thought to be the limit above which positive feedbacks could lead to rapidly accelerating climate change. Lord Stern, the highly respected economist working in the field of climate change, states (2) that a large proportion (perhaps three-quarters) of the fossil fuel reserves owned by the oil, gas and coal corporations globally would not be able to be used without a large risk of dangerous climate change. This estimate does not take account of some of the less conventional fossil fuel sources, including oil from tar sands and shale gas. This argument is also made in the recently published excellent book The Burning Question by Mike Berners-Lee and Duncan Clark (3), who give a figure for the carbon dioxide that could be released while limiting the risk of dangerous climate change of about 700 billion tonnes, compared with the 2,800 billion tonnes which would be emitted if all the fossil fuels on the energy companies’ books were burned. This book also highlights the huge amounts of money being spent by fossil fuel companies on lobbying, particularly in the USA, against any restrictions on their emissions.

In contrast, the World Energy Council (representing governments, private and state sector organisations, and NGOs in the energy field) in a recent statement (4) predicts a large increase in fossil fuel use by 2050, and says that a version of carbon capture and storage (CCS) on a huge scale would be necessary to meet its greenhouse gas emission targets (see later discussion in this article).

Oil/tar sands and other environmentally disastrous sources

Oil from tar sands has larger carbon emissions per unit of energy than conventional oil and its extraction pollutes large areas of land and water (5). The potential quantities in Canada and elsewhere are very large. The EU is trying to restrict the import of oil from tar sands on the basis of its greater climate change impact, but Canada (supported by the UK) is fiercely opposing this.

Major environmental damage can also result from the exploitation of other similar fossil fuel sources, such as oil reserves in the Arctic. An attempt to safeguard the Yasuna National Park in Ecuador (6), an area of extraordinary biodiverse richness, by asking the international community to pay this low income country half the value of the oil resource to not proceed with drilling, failed due to lack of response.

Shale gas

There are large quantities of natural gas, mainly methane, in shale rock formations in many countries. This can be extracted by ‘fracking’, deep drilling and the injection of large quantities of water containing chemicals of varying toxicity under high pressure to crack the rock and allow the release of the gas. The USA is extracting significant quantities of shale gas. In the relatively closed market of the USA, which has little export market for the gas by pipeline and limited port facilities for sea exports by tankers, this has reduced the price of gas, creating a shift from coal-fired electricity generation to gas. The resulting surplus coal has been sold on the world market, reducing its cost, and encouraging greater coal burn in other countries, including the UK. However, in the USA, gas prices have since increased significantly from their initial low value, and are predicted to rise further.

The UK is believed to have quite significant quantities of shale gas. A recent report from the British Geological Survey (7) estimated there could be about 1,300 trillion cubic feet (36 trillion cubic metres) in the north of England and Wales, which if 10-20% could be extracted, would supply the UK for several decades. However, given the relatively dense population and stricter planning constraints in the UK, the proportion that can be extracted may be significantly less than this. Because a well only produces gas economically for a limited time, more wells have to be drilled on an ongoing basis to maintain production.

Problems with shale gas exploitation include much local disruption during the fracking process, methane leakage which could add to global warming unless tightly controlled, possible pollution of water sources and problems with treatment of the large amounts of polluted water used. There is naturally much local opposition to potential drilling sites. The UK government is giving strong support to shale gas exploitation through tax breaks, and it denigrates people who oppose it as ‘nimbys’ (8). This is in contrast to their attitude to on-shore wind, where they are giving more power to local people to oppose wind farms.

It is unlikely that shale gas exploitation in the UK would lead to major reduction in gas price, as the UK is linked to the mainland Europe gas market by pipeline.

Of other countries which are believed to have major shale gas reserves, one case where its exploitation might be, on balance, beneficial, is China, where gas is replacing coal in power generation in some places including Beijing. In France, there has been parliamentary opposition to shale gas extraction (9).

Fracking is also being used for shale oil extraction – indeed, it has been for many decades, including in the UK. There is controversy in some US states as to whether this should be allowed, but in principle, it could produce very large quantities of oil.

Role of gas in the energy mix

There could be some economic and technical arguments for the use of UK shale gas in the short term while in transition to a near zero carbon economy. The UK’s main source of renewable energy is wind power, whose output is variable. To complement this on the electricity grid, power stations whose output is flexible and are low capital cost are required at the moment. In contrast to coal and nuclear stations, gas-fired stations meet these requirements, and, assuming low methane leakage from the gas production and transport, these produce about half the carbon emissions compared with coal.

Currently about half the UK’s gas is imported, by pipeline or sea tankers. There is some gas leakage in these routes, and significant energy use in pipelines from very distant gas fields and in liquefying and re-gasifying gas transported in tankers. Local shale gas could therefore be preferable on these grounds. In the longer term, demand side management could match more closely demand to supply on the electricity system. With greater use of renewables, it is likely that more of the heat demand and transport energy will be supplied by electricity. Charging electric vehicles at times of power surplus on the grid (e.g. at night) and use of district scale stores of water heated at times of power surplus for district heating are just two of many means of matching supply to demand. Stronger grid connections with mainland Europe could allow use of more widely distributed and more varied types of renewable energy, especially solar power, greatly reducing the need for fossil fuel systems on the grid (10). Gas and liquid fuels from waste or biomass (possibly enhanced by greater hydrogen content from electrolysis) are further non-fossil fuel sources (11).

The Centre for Alternative Technology has produced a study Zero Carbon Britain (11) showing a scenario for the UK to reach zero carbon emissions by 2030. This does imply very major and rapid investment in renewable energy and energy conservation projects, as well as behavioural changes, but it does show that to meet somewhat less stringent and rapid carbon reduction targets, no additional sources of fossil fuels are needed to support a good quality of life.

One technology often put forward by (amongst others) the fossil fuel industry is CCS, which is claimed could capture a high proportion of the carbon dioxide from power plants and other industrial processes. Although it is claimed all the individual stages have been demonstrated, no full scale demonstration of CCS has been built. This may be as much to do with the low price of carbon credits in the EU emissions trading scheme as to technical difficulties. Although there is support in some quarters (12) for CCS as a means of resolving the dilemma of much more fossil fuel availability in relation to the carrying capacity of the atmosphere for carbon dioxide, it seems unlikely that CCS could have a large enough impact on the timescale needed to limit carbon emissions to the required extent if anything like the known fossil fuel reserves were to be used.

Benefits to the UK balance of payments and government tax take from shale gas in the short term could, in principle be used to fund massive energy efficiency projects, renewables and sustainable transport. However, past experience with North Sea oil and gas is not a hopeful precedent as much of the revenue from this was spent on imported, mainly ephemeral, consumer products. Also, the government is giving permission for a large number of gas-fired power stations guaranteeing them a market for their output for a long time. (13)


To prevent dangerous climate change, global carbon emissions need to be reduced rapidly, and this means leaving most fossil fuel reserves in the ground. It is clear that such restrictions would be strongly opposed by the powerful fossil fuel lobbies.

The government’s support for the import of oil from tar sands into Europe is totally incompatible with the aim of reducing carbon emissions. Although there could be a technical and economic case for exploitation of UK shale gas in the relatively short term (if it can be shown that problems that occurred in the USA, such as pollution of water supplies, could be prevented by more effective regulation), politically it is clear that the government’s intentions are for exploitation to the fullest extent for as long as supplies last, despite this being inconsistent with stated greenhouse gas reduction targets.

It is vital that a global deal limiting greenhouse gas emissions is reached soon, to prevent emissions increasing as more gas is burned without reducing global coal burn.

Martin Quick is a retired Chartered Engineer with a background in the energy industry.

Download pdf of shorter version published in SGR Newsletter, no.42 [68KB]

(current at the date of publication)

1. IPCC (2013). Fifth Assessment Report: Working Group I. Summary for policy-makers.

2. The Guardian (2013). Carbon bubble will plunge the world into another financial crisis – report. 19 April.

3. Berners-Lee M, Clark D (2013). The Burning Question. Profile Books. IBSN 978-1781250457

4. World Energy Council (2013). World Energy Council Release.

5. Wikipedia (2013). Oil sands.

6. The Guardian (2012). World’s conservation hopes rest on Ecuador’s revolutionary Yasuni model. 3 September.

7. British Geological Survey (2013). New shale gas resource figure for central Britain.

8. Daily Telegraph (2013). You must accept fracking for the good of the country, David Cameron tells southerners. 11 August.

9. Sierra Club (2012). France to ban fracking. 12 May.

10. Wikipedia (2013). European Super Grid.

11. Centre for Alternative Technology (2013). Zero Carbon Britain 2030.

12. Allen M (2013). Trillion tonne budget means carbon capture is not optional. The Conversation. 10 October.

13. BBC (2012). Gas fired power stations to be encouraged by government. 3 December.

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