JOHANNESBURG (miningweekly.com) – Amid rising global energy demand, University of the Witwatersrand visiting adjunct professor Adam Luckos urges developing countries to embrace greener energy principles.
To do this without jeopardising economic growth, he suggests that developing countries, where coal is the most viable indigenous energy source, invest in clean coal technologies (CCTs).
“Reliable and affordable electricity supports prosperity, enhances living standards and helps to alleviate poverty; however, climate change and health issues have to be addressed,” he told delegates at the Fossil Fuel Foundation’s Clean Coal Technologies conference, in Glenhove, on Wednesday.
According to Luckos, CCTs facilitate the use of coal in an environmentally satisfactory and economically viable manner. A basic approach, he suggested, was to reduce emissions by reducing the formation of pollutants and cleaning the flue gases after combustion.
A parallel approach is to develop more thermally efficient systems so that less coal is used to generate the same amount of power. In this regard, Luckos said a one percentage point increase in a plant’s thermal efficiency can reduce carbon dioxide (CO2) emissions by between 2% and 3%.
Improved energy efficiency makes big changes, but deep cuts of CO2 can only be achieved by adopting carbon capture and storage (CCS), he added.
However, CCS is advancing slowly, Luckos noted, as a result of high costs and a lack of political and financial will.
Global CCS research and development spend exceeded $1-billion a year over the 2009 to 2013 period, but has fallen sharply since then, he said.
Consequently, he highlighted that CCT is increasingly being suggested for use at supercritical (SC) and ultra-SC coal-fired power plants without CCS, which run at a thermal efficiency of between 42% and 48%. These are also known as high-efficiency, low-emission (HELE) plants.
COMMERCIAL AND EMERGING CCT
While some of the CCTs are now commercially available, Luckos highlighted that others are still at the demonstration or research stages.
Commercial HELE technologies include pulverised coal (PC) combustion in SC steam boilers with single and double reheat, he said.
However, he warned that while PC is the “most-commonly used technology in coal-fired power plants”, PC combustion has not always been appropriate for coals with a low volatile matter and high ash content.
Other CCT options include fluidised-bed combustion in circulating beds with SC, as well as combined heat and power.
“Commercial HELE technologies, if deployed, can reduce CO2 emissions from the entire power sector by around 30%,” Luckos stated.
Demonstrated CCTs, meanwhile, include integrated gasification combined cycle and a pressurised fluidised-bed combustion with a combined cycle.
In this regard, Luckos lamented that several demonstrations and commercial projects have been hindered or cancelled as a result of lacking political or financial support. Additionally, the deployment of safe transport and storage infrastructure is also a barrier.