A study of South Africa's offshore wind energy resources by researchers from the Stellenbosch University Department of Mechanical and Mechatronic Engineering indicates that wind turbines installed off the KwaZulu-Natal and Western Cape coasts could potentially supply between 15% and 800% of South Africa’s yearly electricity demand depending on the depth at which the turbines are installed.

The study by Stellenbosch University Department of Mechanical and Mechatronic Engineering researchers Gordon Rae and Dr Gareth Erfort was published in the Journal of Energy in Southern Africa. It is a comprehensive first assessment of South Africa’s offshore wind energy resources and was aimed at identifying the most suitable regions for the development of wind farms.

Their assessment shows that the most suitable regions for the development of offshore wind energy are Richards Bay within the 10 km coastline buffer and 15 km offshore south of Richard Bay, Durban within the 10 km buffer and 25 km offshore of KwaDukuza and Struisbaai within the 10 km buffer zone and 15 km offshore.

“Our study revealed that South Africa has an annual offshore wind energy production potential of 44.52 terawatt hours (TWh) of electricity, if wind turbines were to be installed in shallow waters of depths of less than 50 m and 2 387.08 TWh with wind turbines in deeper waters at depths less than 1 000 m,” they said.

Their calculations show that the estimated 44.52 TWh could theoretically meet 14.9% of national electricity demand. Similarly, 2 387.08 TWh could theoretically satisfy the country’s annual electricity demand eight times over.

“These figures show that we should not ignore the significant potential of offshore wind energy, especially if we consider the International Energy Agency’s prediction that global electricity demand will increase by about 56% by 2050,” the researchers say.

Assessing offshore wind energy resource is essential for the development of local offshore wind industries. Quantifying these resources is a fundamental first step for the development of markets for offshore wind energy, and offers valuable insight for the planning of energy security at national level and private sector investment.

There is an opportunity to transition from coal power to offshore wind technology, which is a clean electricity generation alternative that presents power security and decarbonisation opportunities for South Africa. By tapping these resources, South Africa could also decrease its carbon emissions significantly, they add.

Rae and Erfort used geographic information system methods to do their assessment and included marine protected areas sourced from the World Database of Protected Areas, which is the most comprehensive database on terrestrial and marine protected areas. The marine protected areas were included in the study to create so-called no-go zones.

“It was important to include these no-go zones as they illustrated what portion of the exclusive economic zone would be inaccessible to offshore wind energy from an environmental perspective,” the researchers say.