Johan Kotzé


Johan Kotzé is an engineer whose complex research work into solar energy can easily leave you baffled.

Yet it’s hugely important stuff that should one day see South Africa building “clean energy” power stations and supplying us all with cheaper electricity.

Kotzé (29) did his doctorate at the department of mechanical and mechatronic engineering of Stellenbosch University. He’s a senior member of its solar thermal energy research group, developing ways to store thermal energy more effectively.

At the moment, solar thermal energy is stored in molten salts, but the storage temperature is limited and that limits the efficiency of the power plants.

“My research is looking for ways to increase the temperature the energy can be stored at by storing it in liquid metals,” he says.

“It really isn’t that difficult in theory.”

But actually it is difficult, and quite novel, which is why Kotzé won an award from the South African National Energy Development Institute for making a significant contribution to the energy environment.

He won the Young Researcher Award of 2013 for his concepts around concentrating solar power.

He has presented his research at several international forums, and his was the only paper addressing this topic at the global SolarPACES 2011 symposium. A year later several German and US consortiums presented similar work following in his footsteps.

The overall goal of his research is to lower the cost of electricity, although this method of thermal energy storage still requires a lot of research before it can be implemented safely, he says.

Kotzé and nine colleagues are now starting the TIA Helio100 project to develop the next generation of concentrating solar power technology.

“Eventually the aim is to build large power plants. When the coal runs out we will be ready to implement this technology in South Africa and build it locally. The main goals are energy security and job creation because this will be a completely local solution,” he says.

It’s impressive and very necessary work, but Kotzé shrugs off the praise.

“I don’t think I’m special in any sense. Our research group is a really excellent bunch of people.” — Lesley Stones