File photo: While CO2 is not toxic, it can asphyxiate people if they are exposed to large volumes  as happened in 1986 when at least 1 700 people and 3 500 animals died when a concentrated cloud of volcanic CO2 gas bubbled to the surface of Lake Nyos in Cameroon.

Durban - KwaZulu-Natal has been earmarked as the most likely dumping ground for millions of tons of carbon dioxide gas produced by industry.

The Mercury has learnt that plans are afoot to start injecting carbon dioxide (CO2) into deep underground rock formations north of Lake St Lucia, or possibly in the Algoa area near Port Elizabeth.

This pilot project, due to start within four years, could be the forerunner of more ambitious plans to bury massive volumes of CO2 gas beneath the seabed off Durban and the Zululand coastline, as part of South Africa’s strategy to reduce the volume of CO2 and other greenhouse gases heating up the atmosphere and exacerbating global climate change problems.

Known as carbon capture and storage, the controversial technology is being used to bury CO2 in parts of Europe, Australia, the US and oil-rich north Africa.

Responding to questions on plans to set up the country’s first CO2 storage demonstration site in 2017, South African Centre for Carbon Capture and Storage manager Brendan Beck declined to identify the locations of the two pilot site alternatives.

 

However, he said, one was north of Lake St Lucia, inland of the iSimangaliso Wetland Park, somewhere in the uMkhanyakude region.

A recent technical report on underground carbon storage by the Council for Geoscience suggests that the pilot site is on the Makhatini Flats, near Lake Sibaya.

Beck said the final decision on whether to locate the dump in KZN or the Eastern Cape would depend on the results of further geological studies to identify the most suitable storage site.

From a cost perspective, the Geoscience report recommends KZN as the most attractive site, as it is closer to the major industrial sources of CO2 in Gauteng and Mpumalanga.

Beck said that rather than being transported in pipelines, the CO2 would probably be trucked through KZN before being “injected” under pressure and buried at a depth of about 800m.

According to the Geoscience technical report, South Africa generates more than 400 million tons of CO2 a year, mainly from Eskom power stations, fuel refineries, cement-making and other forms of heavy industry.

Although this amounts to roughly one percent of global carbon emissions, South Africa is the biggest “climate gas polluter” in Africa and produces more CO2 on average for each person than China, Brazil or India.

While CO2 is not toxic, it can asphyxiate people if they are exposed to large volumes – as happened in 1986 when at least 1 700 people and 3 500 animals died when a concentrated cloud of volcanic CO2 gas bubbled to the surface of Lake Nyos in Cameroon.

However, Beck and other proponents of carbon capture and storage argue that there is little likelihood of people dying because of an accidental leak of CO2 into the air during pipeline transport or after it is buried deep underground in geological rock cavities.

Beck suggests CO2 from a pipeline leak would dissipate rapidly, while an underground leak would probably be detected and sealed well in advance.

The gas was likely to escape in only small quantities if it had to pass through rock barriers. If it leaked to the surface, it would dissipate quickly.

Several questions remain about indirect effects on people and the environment.

Carbon dioxide is slightly acidic and can dissolve certain rocks, adding to the concern about the pollution of underground water. - The Mercury