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In its yearly World Energy Outlook 2018, the International Energy Agency (IEA) forecasts that coal will remain the largest single source of electricity generation through to 2040, at 26% of global electricity.
Renewables will have a role to play as future energy sources for South Africa, region and globally, but, other than nuclear and large-scale hydro, coal is the only source able to provide baseload electricity and therefore the only means to guarantee energy security in the country.
Imported natural and liquefied natural gas is expensive and prone to political constraints, and shale gas has yet to be proven. For every megawatt produced by wind and solar, an equal megawatt produced by baseload is required as backup. Coal can meet such needs and be the source of choice for such backup.
South Africa has the capacity to solve the coal-fired heat, power, and carbon-based manufacturing industry needs of sub-Saharan Africa if only the current situation of irregular coal quality, poor maintenance of boiler technology and more efficient – and tolerant – processes can be accepted and developed technologically to suit the region.
With up to 200 years of resources of this valuable carbon in the form of coal, the country could once again be the power and manufacturing house of Africa, given the development of its own regionally compatible clean coal high efficiency low emissions (HELE) technologies to meet the future demand.
Of specific relevance to South Africa would be the circulating fluidised bed combustion boiler (CFBC) technology which operates at temperatures below 900 ºC and, in so doing, has the capacity to both capture sulphur dioxide greenhouse gases inbed and nitrous oxide owing to low temperature combustion – with the help of limestone or dolomite – and reduce carbon dioxide (CO2) owing to its advanced efficiency. Hundreds, if not thousands of such boiler plants are now being installed in China, India and South-East Asia to meet the ever-increasing energy and industrialisation needs of those countries while also complying with environmental legislation.
“Not one CFBC exists in South Africa, but several are being built in the Southern African Development Community region,” notes Fossil Fuel Foundation director and cofounder Dr Rosemary Falcon.
CFBC plants are now being built to be increasingly efficient, ranging from supercritical to ultra-supercritical and advanced ultra-supercritical designs. With each level of increased efficiency, carbon emissions are dropped considerably.
Falcon asserts that this technology has the additional advantages of using larger sized coal, a wide tolerance of quality variations in its feed and – of greater importance – it can effectively and efficiently cofire biomass and coal as well as a range of waste materials.
Tests conducted by doctoral students at the University of the Witwatersrand have shown that a South African high ash discard coal can burn as efficiently as a European low ash coal, while additional tests have shown the compatibility of biomass with coal in such combusting environments.
Biomass in the form of bamboo grown on mine rehabilitated mines is currently being investigated as the biomass of choice in future cofiring operations in such boilers. Biomass is regarded as CO2-neutral as plants absorb CO2 during their growth. Bamboo also has the potential to provide source material for significant micro-industries for communities in the vicinity of mines once mine closure has taken place. China has a multibillion-dollar industry in such materials.
Addressing the Impacts of Coal
All aspects of production and use have an environmental impact on air, land and water and it is these that have demanded attention and are the target of green associations globally. Apart from land and water, the key is the production of CO2 from coal combustion, followed by the remaining greenhouse gases sulphur oxide and nitrous oxide and particulates.
What is little advertised is the fact that many new clean coal technology HELE concepts have been developed and are now proven, available, installed and operating in hundreds if not thousands of coal-fired plants globally – except in South Africa.
“Medupi and Kusile represent the very least that South Africa’s Eskom has embarked upon and this in the most limited of ways,” claims Falcon.
Globally, mining is progressing towards cleaner and safer mechanised methods, beneficiation has reached optimum levels to produce better quality coals for improved utilisation efficiency and therefore reduced CO2 during utilisation, boilers are now in use that capture CO2 before, during and after combustion. Also, the sulphur oxide, nitrous oxide and particulates can be reduced to zero or minimal levels, well below the stringent World Bank standards.
CO2 capture, storage or utilisation are projects under way or in operation in over 24 countries globally.
However, little is found in South Africa in this regard, apart from the good intentions of Eskom in the building of the supercritical power stations, Medupi and Kusile. These may be CO2 capture ready in due course but South Africa has yet to prove that it has significant geological storage capacity for CO2 on land. Currently, a pilot scale drill to test storage capacity is under way in KwaZulu-Natal and Eastern Cape sediments. CO2 utilisation projects are only at the stage of laboratory or small pilot plant scale investigations. So much more needs to be done in support of the cleaner use of coal in the country, she says.
Of additional concern in South Africa are the reducing grades of coal being sold into current power stations and industrial boilers, all of which were designed for better qualities. The consequence of this practice leads to more tons of coal fed into boilers to produce a given requirement of heat or power, and this, in turn, leads to higher proportions of CO2
The answer is for South Africa to firstly recognise its own coal qualities, which are significantly different to those known in Europe, China, and the US, and secondly to develop its own technologies more suited to the coals in the region. “This is of vital importance to reduce emissions in future and, equally importantly, could lead to the commercialisation of locally designed and manufactured plants into the Southern African region.”
Notably, in terms of income for the national economy, coal has also provided the highest foreign exchange earnings of all mineral commodities for the past eight years, beating gold, diamonds and platinum, and this is likely to continue till mid-century with exports to South-East Asia.
Apart from providing the country’s baseload heat and power, coal also provides 100% of the country’s carbon materials – coke and char – which are used to produce the iron and steel for heavy industry manufacturing such as cars, fridges, and steel for buildings and bridges. Likewise, coal provides the key ingredient in the manufacture of cement, concrete, lime, bricks, paper, pulp, explosives, plastics, clothing materials, food, pharmaceuticals, and a host of related carbon-based products. Few realise that coal provides approximately 30% of the country’s liquid fuels, petrol, diesel and paraffin. Without coal, the country would need to import all such materials and products.
Falcon concludes that coal addresses vital socioeconomic issues which are little understood by those claiming that renewables would replace the jobs lost if the coal industry were to cease to exist.