There are many misconceptions about the value of wind and solar power, including that it is expensive and unreliable. Joanne Calitz is a young energy system modeller at the CSIR who uses mathematical modelling to quantify the true value of renewable energy in South Africa.

“One of the biggest challenges has been convincing people that renewable energy can contribute stable and reliable energy to the South African power system at very competitive costs. This is why we need to create a reliable knowledge-base which people can use to make informed decisions about renewable energy,” says Calitz.

After graduating in industrial engineering at the University of Pretoria in 2009, Calitz was introduced to energy system modelling when she worked for Eskom for five years.

“Energy system modelling entails simulating a power system - such as South Africa's power system - mathematically in a software tool, in order to perform analysis on how the power system behaves under a certain set of data assumptions and scenarios.

“Since a power system is a complex, integrated system, simulating it allows you to better understand the linkages and effects which different components of the system have on one another.”

During her years at Eskom, Calitz specialised in the optimisation of power systems. She then learned that the CSIR had established an energy centre and that it was trying to grow its science, engineering and technology base that focuses on energy.

“There are only a few energy system modellers in South Africa. I read about the energy centre and the CSIR in general and felt that it was the perfect environment to conduct meaningful power system studies for both research and application in industry.”

Since joining the CSIR in March 2015 she has had the opportunity to work on multiple projects, including a study in 2015 which analysed the financial benefits of renewable energy in South Africa, a first-of-its-kind for the country.

The researchers found that renewable energy from South Africa's first wind and solar projects created R4 billion more financial benefits to the country than they cost during the first six months of 2015.

South Africa has abundant wind and solar energy resources, but these have not been fully exploited for the country’s economic benefit. The CSIR partnered with Germany’s Fraunhofer Institute for Wind Energy and Energy System Technology (Fraunhofer IWES) to quantify the combined aggregation effects of these two energy sources. “A highlight of 2015 was the opportunity to spend a month in Germany at Fraunhofer IWES to work and be trained on the wind and solar photovoltaic (PV) aggregation study.” The results indicate that wind and solar PV installations provide smooth power output when the power plants are dispersed over a large area. It also indicates that the magnitude and cost competiveness of wind power in South Africa is on par with solar PV.

“Ensuring that this information is incorporated in energy planning studies will prove that South Africa can confidently pursue a large renewable-based mix in its power system,” says Calitz.

She had never heard of energy system modelling as a career before starting to work. “I gravitated to engineering because I always loved mathematics, the sciences and problem solving. However, there is no specific undergraduate engineering course for energy system modelling in South Africa. At the CSIR’s energy centre, there are people who initially trained as mechanical, chemical and electrical engineers. Most people only specialise in energy-related fields during their post-graduate studies.”