Emissions ‘unavoidable’ even if cleanest coal generation technology is used – report

18th August 2021 By: Simone Liedtke - Writer

Dr Ranajit Sahu, an engineer with more than three decades of experience in power plant design, has found that large quantities of greenhouse-gas (GHG) emissions are “unavoidable”, even if the cleanest available technology is used for new coal-fired power generation.

South Africa’s Integrated Resource Plan for Electricity of 2019 (IRP 2019) claims that new coal generation capacity will be cleaner because high-efficiency, low-emission (HELE) generation technology will be used, although it does not state which kind.

Sahu assessed the potential air emissions of the most likely types of HELE technology that could be used as part of a report commissioned by the Centre for Environmental Rights (CER) for groundWork, the Vukani Environmental Movement in Action, as well as the African Climate Alliance.

He found that, even in the best-case scenario in which the cleanest available technology is used, “large quantities of GHG emissions are unavoidable”.

In particular, Sahu considered two likely technologies that could be used, namely pulverised coal units and circulating fluidised bed technology.

He found that pulverised coal units, even when operating at ultra-supercritical efficiency, would not be able to capture their emitted carbon dioxide owing to extremely high costs.

Circulating fluidised bed technology, which is considered preferable in the IRP 2019, owing to its ability to handle low-quality coal, emits two to ten times more nitrous oxide than pulverised coal technologies, according to Sahu’s findings.

Nitrous oxide is a potent, long-lasting GHG with a global warming potential 300 times that of carbon dioxide.

“I want to stress that contrary to implications in the IRP 2019 and the Ministerial determination, there is simply no such thing as ‘clean coal’, regardless of whether HELE technologies are used to minimise air emissions from coal (or gas derived from coal),” Sahu stated.

The report is the latest research that supports the view that new coal generation in South Africa will be “unnecessary, costly and highly detrimental” to the environment.

“New coal generation flies in the face of the South African government’s obligation under international and South African law, including the South African Constitution, to take all reasonable measures to protect its people from the impacts of climate change,” Sahu concluded.