SA's coal clean-up digs deep with gasificationComment on this story
Johannesburg - South Africa produces almost all of its power from coal-fired plants that pollute the air with dark clouds of smoke and fail to generate enough electricity to avert blackouts.
Now, if scientists are right, coal in the future could produce electricity without ever leaving the ground.
State power utility Eskom wants to address both South Africa's supply shortfall and its carbon emissions by burning its vast coal reserves underground to produce gas for more efficient, cleaner electricity.
An experimental technology dubbed Underground Coal Gasification (UCG), which is also being developed in Australia, Canada, India and China, could be especially important for South Africa, which relies on coal for nearly 90 percent of its power.
“It could have the double benefit of boosting electricity and reducing carbon emissions,” said Steve Lennon, an Eskom sustainability executive leading the UCG programme.
UCG involves drilling wells to previously unrecoverable coal reserves hundreds of metres underground and injecting steam and oxygen to ignite a combustion process which produces a synthetic gas that can be used as fuel.
Separate, steel-lined, sealed wells are drilled to carry up the gas.
Scientists say the process promises to be much cleaner than coal mining because much of the carbon dioxide, ash and other pollutants produced can be stored deep underground.
The gas can be used to replace coal in existing power plants, fire gas turbine facilities or for heating and cooking.
The approach promises to be cheaper than coal mining too because it eliminates transportation and ash disposal costs.
It could also massively increase global coal reserves as it burns coal far deeper than miners can reach.
Experts estimate it could more than double South Africa's reserves.
South Africa is the 12th largest carbon emitter in the world and by far the biggest on the continent, prompting the government to discuss legislation to clean-up its power sector.
Ministers may now choose to push ahead with cleaner options such as wind, solar, nuclear and shale gas.
However, with the world's seventh-largest reserves, coal is likely to remain an important source of power generation.
“Coal is here to stay in South Africa and UCG offers the opportunity to use that coal in a much cleaner and more efficient fashion,” said Eskom's Lennon, adding that he was in discussions with private companies about investing in UCG.
Eskom has been developing UCG for 10 years and is investing a further 1 billion rand in research over the next five years, when it hopes to give the green light for the technology to be rolled out.
The utility is looking for ways to keep up with rising power demand and rein in spiralling costs, which threaten to push electricity prices above inflation and burden Africa's most developed economy.
Lennon says Eskom is committed to funding new technology and UCG research is not under threat, although many hurdles remain.
“When we first started the biggest challenges were technological,” Lennon said.
“We've overcome that.”
“Now the challenges we face are regulation, legislation and the next big one will be costs. Can we make sure this is a cost-competitive technology? The indications are we can.”
Lennon says he hopes UCG will produce power at around $5-$6 per kilojoule, less than half the cost of its obvious competitor, imported liquefied natural gas (LNG), but around double that of shale gas in the United States.
For now, UCG remains a frontier technology and much could change in global energy in the five years before South Africa expects to harness it.
It could also face resistance from environmentalists who are concerned about how UCG can be controlled and its potential dangers accurately assessed due to the depth of operations.
There is also concern that the process in the long term could raise the country's carbon output, not lower it, by sustaining the use of the fossil fuel.
Yet many experts are optimistic.
“UCG has very large potential. It will probably be the successor to conventional coal mining,” said Xavier Prévost, senior coal analyst at Pretoria-based XMP Consulting.
“It fits in perfectly with South Africa's needs because it will create energy and minimise emissions.” - Reuters