STATE power utility Eskom is in an unenviable bind in terms of its coal supplies and the unusually long period of rain experienced in the north-eastern parts of South Africa‚ University of the Witwatersrand coal expert Rosemary Falcon said on Friday (07/03/2014) morning.
South Africans endured the country’s first load shedding in six years on Thursday‚ raising the spectre of the 2008 blackouts that cost the economy billions‚ although Eskom spokesmen told radio stations on Friday morning that the situation was looking more positive.
“It is nothing more or less than that — in other countries when coal gets wet there is space capacity (that can be put into play when coal stockpiles are wet)‚” said Prof Falcon‚ the South African National Energy Development Institute chair in clean coal technology.
Business Unity South Africa said on Thursday it would request an urgent meeting with Energy Minister Ben Martins and Public Enterprises Minister Malusi Gigaba after the load shedding‚ in two-hour bouts‚ hit homes and industry across South Africa. It was the fourth electricity emergency in the country this year.
The reasons Mr Gigaba gave for the controlled power cuts — depleted coal stockpiles and rain — echoed those of 2008‚ sparking debate on what Eskom had done‚ and could do‚ to keep its coal dry.
“One should foresee this type of thing (the rain of the past two weeks). One would like to see them do some strategic planning‚” said economist Richard Downing.
Since 2008‚ the utility has redesigned stockpiles to ensure better drainage and increased their size‚ from three to five days’ worth to more than 40 days’ worth‚ Eskom spokesman Tony Stott said.
Prof Falcon said Eskom used fine coal‚ which was part of the problem: “The finer the coal‚ the higher the water content.” Many other countries use coal that is not powdered‚ and South Africa exports much of this type of coal.
Eskom wants coal declared a “strategic resource” to secure supplies and force mine operators to process some output locally as its coal-fired power stations‚ which produce almost 90% of South Africa’s electricity‚ require a continuous supply. It has long bemoaned the lack of supplier market competition‚ the export of Eskom-grade coal to India and China‚ above-inflation cost increases in the mining industry and a lack of new coal mining projects.
Mr Gigaba said Eskom had depleted dry coal stockpiles at some power stations‚ forcing it to use wet‚ poor-quality coal that reduced output.
Also on Wednesday night‚ three units at Mpumalanga’s Kendal power station were “lost”. To add to Eskom’s woes‚ dam levels were low at the Drakensberg and Palmiet pumped storage power stations‚ both of which act as reserves‚ and all of this was worsened by the loss of energy imports from Zimbabwe‚ Mr Gigaba said.
Prof Falcon said about 50% of South Africa’s coal mines were open cast‚ which meant it was difficult or impossible to mine during heavy rain. This lead to stockpile depletion during rainy periods.
Also‚ coal of the fine powered type used by Eskom “glued” to surfaces when wet‚ and wet coal‚ when released into a boiler‚ absorbed heat and reduced output‚ she said.
Prof Falcon said some coal stockpiles in wetter climates were kept in massive bins or hoppers‚ but those countries often bought larger coal that was not so friable.
Stockpiling is also a fine art — too large a stockpile is a fire hazard‚ she added‚ saying that Eskom could perhaps cover more of its conveyor belts‚ used to get the coal into some power stations‚ although some were simply too long.
Mr Stott said wet coal made coal handling more difficult and slowed it down. Eskom powdered its coal before it was blown into a boiler‚ meaning that wet coal that clumped was less efficient.
“The problem is that most of our power stations are in Mpumalanga (in north-eastern South Africa) and 90% of our coal mines are there too‚” he said. – Sue Blaine © BDlive 2014