The most plausible argument put forward by opponents of immediate action to mitigate global warming is that some form of ‘clean coal’ technology will emerge that will obviate any need for costly changes in our current way of doing things.
The term ‘clean coal’ is sometimes used to refer to ‘ultra-supercritical’ or ‘high efficiency, low emissions’ (HELE) coal-fired power stations. Despite these impressive sounding description, HELE plants provide only a 30 to 40 per cent reduction in emissions relative to standard coal-fired power plants. They aren’t as clean as gas-fired fossil fuel plants, let alone renewables (or nuclear power, though this isn’t a viable solution for other reasons).
‘Clean coal’ is also used to refer to the idea of ‘carbon capture and storage’, (CCS) in which the carbon dioxide produced in coal-fired power stations would be captured before being emitted into the atmosphere, then pumped into underground storage, or captured through ‘biosequestration’ into products such as biochar.
CCS was an appealing idea for a coal producing country like Australia. Enthusiasm for the idea led to the establishment of the Global CCS Institute in Melbourne. However, the Institute’s own website shows that CCS is not a viable option. After decades of work, there is exactly one operational power plant using CCS, the Boundary Dam project in Canada. Two more, both deeply troubled, are under construction in the United States.
Even if all the coal-fired CCS power plant projects anywhere in the world that are listed by the Institute as possibly happening by 2030 are included, the total amount of CO2 captured would be less than 20 million tonnes a year. That’s about what Australia generates in two weeks.
To sum up, what’s usually called ‘clean coal’ isn’t clean. The real thing, cost-effective coal-fired power stations with CCS, is never going to happen.