Coal after Paris
The December 2015 Paris Agreement aims to hold the average global temperature increase to well below 2°C and to pursue efforts to limit the global temperature increase to 1.5°C. Greenhouse gas (GHG) emissions should peak as soon as possible and then reduce rapidly after peaking, to reach a balance between GHG sources and sinks by the second half of this century. It also says that finance flows should be consistent with a pathway to low-emissions of GHG. A technology mechanism has been introduced to strengthen cooperative action on technology development and transfer, as it is recognised that accelerating, encouraging and enabling innovation is critical. The importance of capacity building for developing countries was also identified to facilitate technology development, dissemination and deployment, as well as the timely and accurate communication of information – among other aims.
So this was an encouraging result. There is a target agreed by 195 countries and mechanisms established to encourage the transfer of technology and finance to poorer parts of the world. Many of the emerging economies do not have reliable access to electricity, but do have substantial coal resources or access to cheap coal.
Thus regardless of the aims agreed in Paris, the IEA expects that 44% of energy needs will still be met by fossil fuels in 2050. This means that high-efficiency, low-emissions (HELE) technologies and carbon capture and storage (CCS) are vital if the Paris ambitions are to be realised. The mechanisms agreed in Paris are important as it is in Asia mainly that most coal developments will take place.
Currently, ultra-supercritical (USC) coal power plants emit almost 20% less CO2 per unit output than traditional subcritical ones. Developments in advanced ultra-supercritical (AUSC) plants mean that a plant operating at 51% efficiency (net LHV basis) would emit up to 28% less CO2 than a subcritical plant. In 1993, the first USC unit was installed in Japan. All units built there are subsequently also USC and operate at about 45% efficiency. Japan has a technology roadmap to 2030 to increase the efficiency of coal-fired plants and develop carbon capture. They also aim to build an AUSC plant.
In 2006, the first USC unit was commissioned in China. By 2017, USC capacity in China will be over 208 000 MWe, with efficiencies of up to 46 – 47%. USC units operate in more than ten countries, including China, Germany, India, Japan, Korea and the US, and the first units are under construction in Malaysia (2015) and Taiwan (2016). There are further coal-based transformational technologies under development, including the integration of gasification-based units with fuel cells, chemical looping combustion and various cycles that use supercritical CO2 as a working fluid to drive a gas turbine to achieve very high efficiencies with lower capital costs.
In China in 2014, 67% of total power generated was supplied by coal. The policy of closing small old inefficient coal-fired power plants and replacing them with large efficient ones is significantly improving the average efficiency of coal use. At the same time, China is diversifying its fuel mix to include significant quantities of wind, solar and hydropower, with a rise in nuclear power.
Coal consumption and coal imports to India will continue to grow, as will its demand for energy. India has a national programme for AUSC plant, with a target efficiency of 49% (LHV). There is a huge market in India for clean coal technologies (CCT). But extensive research is required to match CCT to Indian coal, which typically has a high ash content.
In the EU, coal will remain important for the foreseeable future. Currently, coal supplies more than 26% of electricity generated and is on a par with nuclear and renewables.
Although coal power may well decline further in the US, it will continue to be the second largest user of coal after China. There is a substantial clean coal R&D programme underway in the US with some focus on developing AUSC plant and establishing CCS. The US is funding an advanced combustion programme and investing in pressurised oxy-combustion research for carbon capture as part of a drive to establish second generation coal based CCS schemes with lower efficiencies penalties and reduced capital costs.
Coal will continue to make a vital contribution to the energy mix until 2050 at least, across most of the world. Any growth in coal use is not consistent with current climate policies, unless HELE technologies and CCS are included. The IEA Clean Coal Centre has an important role to play in analysing and disseminating information and knowledge on these practical ways to improve efficiency and reduce emissions from fossil fuel-fired plants.
About the author: Debo Adam is Communications Manager at the IEA Clean Coal Centre.