Potential contribution of coal to the future global energy system

Using a bottom-up type global energy model, this article explores in detail the potential role of coal over the 21st century and focuses on the prospects for coal gasification-based conversion technologies with CO2 capture and sequestration (CCS) under the CO2 stabilization target of 550ppm. The results show that even in the CO2-constrained world, coal can remain one of the important primary energy sources throughout the century on the condition that the resulting CO2 is properly captured and sequestered. Coal’s competitiveness in such a world would increase with the introduction of CCS, but decrease with the leak rate for CO2 stored underground. For the optimal coal use, a common trend toward producing convenient and clean final energy carriers via gasification is observed. Under the CO2 constraint, coal is increasingly converted via gasification with CCS into electricity and hydrogen, thereby providing CO2-neutral energy carriers and facilitating CO2 capture, which helps China and India develop in a sustainable manner. These findings prove to be robust with respect to the costs of gasification-based conversion technologies and CCS. It is suggested that the establishment of reliable CCS technologies and low-cost gasification-based conversion technologies and their transfer to developing regions would raise the value of coal and provide energy security benefits under the CO2 constraint. However, it is also indicated that large-scale introduction of coal with CCS into leaky reservoirs would cause large CO2 emissions from leaks over the very long term.