Coal was probably first exploited commercially in China, though one of the earliest known references to a coal-like product was made by Aristotle. Since the Industrial Revolution, which coal helped to spark, its qualities as an abundant and energy dense fuel have been proven. However, coal’s recent history has a darker, dirtier side, as illustrated by London’s legendary smog (a blend of fog and dusty smoke) that killed an estimated 12,000 people in 1952, and the acid rain that affected north European forests in the 1970s and 1980s.
Coal mining is also risky work; in China some 6,000 miners die every year in accidents. The safety record has vastly improved in the OECD area, and the US Chemical Safety Board reports that oil and gas industry fatalities can be higher than in coal mining. Still, miner deaths like recent ones in Poland and the US grab the headlines and reinforce the dangerous image of the industry.
While many people may associate mining with pollution, hardened communities and a past socio-economic order, coal is still very much part of the present and the future. In fact, coal is the most abundant fossil fuel and accounts for around one-quarter of the global energy mix. Many countries have ample reserves, which means a secure supply. Though 80% of reserves are found in six countries–China, US, India, Russia, Australia and South Africa–more can be found spread around several others. Over half of electricity in the US comes from coal, as it does in Germany. Even in the UK, where mining has receded, coal accounts for 35% of electricity production, much of it imported from Russia. In Poland 93% of electricity comes from coal. In Japan the figure is 29%, reflecting a higher use of oil and nuclear power.
In the reference scenario of the IEA’s World Energy Outlook 2006, coal’s share in the global energy mix is projected to remain roughly constant over the next couple of decades. Countries like India and China–already the world’s largest producer–will see the biggest growth. According to the WEO 2006, these two countries account for over three-quarters of the entire increase in coal use between 2004 and 2030. Over the next 25-30 years, the IEA anticipates a 59% increase, globally, in tonnes of coal burned, of which 81% will go to power generation.
In 2004 coal-fired power plants produced 40% of total world electricity output. High oil and gas prices have improved the attractiveness of coal-fired stations, with new more efficient generators being built or in the planning stage in the OECD. By 2030, the share of coal in electricity output will rise to 44% in World Energy Outlook 2006’s reference scenario. Coal also plays an important, if diminished, role in the alternative policy scenario. Its share in power output falls to 37%, helping stem the rise in CO2 emissions to 31% by 2030, compared with a rise of 55% under the reference scenario.
This appetite will not exhaust reserves too fast: 20 countries have known reserves exceeding 1 billion tonnes, out of a global estimate of about 909 billion, which is enough coal to burn for 164 years. By 2030, at current rates, only 22% of those reserves will have been exhausted.
The main problem with coal is not reserves or price, but emissions. In fact, coal is a very dirty fuel. Effective controls from coal-fired power plants do exist, for sulphur (SOX), for instance, and have led to reductions in acid rain. However, coal is the most carbon intensive of all fossil fuels. A large coal plant, generating 1,000 megawatts of energy may produce enough energy for 1.6 million homes, but it also produces some 6 million tonnes of CO2 per year–the equivalent emissions of two million cars. As an IEA report notes, CO2 control technologies have not been adopted yet. Incentives could be introduced for deploying technologies that lower, or even eliminate, these emissions, whether by mechanisms such as taxes or tradeable emissions permits.
As retrofitting old coal power plants is costly, the industry expects new plants to be equipped with technologies to improve efficiency and cleanliness. According to one report, some 150 new plants are on drawing boards in the US, with one firm unveiling plans to build 11 in Texas alone. Average efficiency of today’s plants is about 35%, and new designs can improve that to around 46%, experts believe. Innovations are in the pipeline to make coal cleaner. Washing coal to remove impurities, filtering smoke for particles or adding some biomass do not deal with the greenhouse gas emissions effectively enough.
One promising way to deal with carbon dioxide is to siphon it off. There are various methods of this so-called CO2 capture, and this all adds to costs. Paradoxically, it also means mining and burning more coal to provide the energy needed to extract the CO2.
Still, capture-ready plants are now being built. Carbon capture basically means storing unwanted carbon dioxide indefinitely, say, by injecting it deep into geologic formations. A report by the Intergovernmental Panel on Climate Change (IPCC) estimates that the earth’s technical storage capacity is at least 1,700 Gigatonnes and perhaps as much as 10,000 Gt of CO2.
Much of the public interest in storage surrounds the risk of leakage. While small amounts of CO2 are harmless, a massive outpouring would be lethal. However, while sudden carbon dioxide releases can happen naturally, in volcanic activity for instance, the chances of these occurring in the context of carbon capture storage are virtually nil. If there is a debate, it is less about safety risks than the possibility of greenhouse gases reescaping back into the atmosphere and so undermining the investment. In practice, tests show that leakage is highly unlikely to happen. For a start, the CO2 is injected beneath impermeable cap rock, which would be monitored for faults. Also, unlike in a volcanic situation, the carbon dioxide is not a pressurised gas, but is introduced as a liquid-like medium which is then absorbed like a sponge deep in bedrock pores that had already locked oil and gas safely away for millions of years. Much of the carbon dioxide would dissolve over time into surrounding saline water or become permanently trapped in rock.
Commercialisation of large-scale capture and storage technology is still a decade away, but tests in the Sleipner sub-sea storage site in Norway, which stocks some 10 Mt of CO2, have been positive (see Norway, ministerial roundtable).
Vigorous investment in cleaner coal technologies and competitive renewable technologies may help alter emissions scenarios, but whether we like it or not, the history of coal as part of our planet’s energy mix is far from over.
- IEA (2006), World Energy Outlook, Paris. Visit www.worldenergyoutlook.org
- IEA (2004), "Control and Minimisation of Coal-fired Power Plant Emissions", Working Paper, available at www.iea.org
- IEA (2004), "Prospects for CO2 Capture and Storage", available at www.iea.org
- IPCC (2005), Carbon dioxide Capture and Storage.
- Parks, James (2006), "Pennsylvania Explosion Kills Coal Miner" at a www.aflcio.org/ , October.
- Socolow, Robert H. (2005), “Can we Bury Global Warming?” in Scientific American, July
- Williams, T. (2006), "Carbon, Capture and Storage: Technology, Capacity and Limitations", PRB 05-89E, Parliamentary Information and Research Service, Canada. Available online.
©OECD Observer No 258/259, December 2006