Since he can remember, Dr Johan Giliomee has been mesmerised by everything about cars, dreaming of one day working with Formula One car technology. The red Lego Ferrari that has been above his bed for twenty years is a testament to this dream.
He would never have thought how quickly his dream became a reality after enrolling for his electrical and electronic engineering degree at Stellenbosch University (SU) in 2018. His remarkable research into the energy usage of minibus taxis and how this energy can be supplied resulted in his master’s dissertation being upgraded to a PhD and, at the same time, being recruited by Jaguar Land Rover (JLR) as a graduate engineer in the UK.
Giliomee’s proud grandfather, Prof Jan Giliomee, Professor Emeritus at SU’s Faculty of Science, hooded him on Tuesday, 10 December 2024, at SU’s graduation ceremony. Prof Thinus Booysen, Professor of Engineering and founder of the Electric Mobility Lab at SU, was his supervisor. Giliomee earned his BEng (electrical and electronic engineering) degree with first-class honours in 2021.
Giliomee’s thesis highlights the urgent need to electrify the paratransit industry in sub-Saharan Africa (SSA), with transport emissions detrimental to planet- and human health. With the minibus taxi as the dominant mode of transport to millions of commuters across the continent, he considered the relatively unknown nature of their operations, the limited range of electric vehicles, electricity scarcity in the region, and the electrification of this industry in a comprehensive energy analysis. This included the energy usage of an electric minibus taxi and how this energy can be supplied.
His research showed that energy efficiency heavily depends on the driving scenario of minibus taxis, and therefore, he analysed urban, inter-city, uphill, and downhill driving scenarios, with results ranging from 0.29 to 0.51 kW per hour/km. On average, an energy efficiency of 0.39 kW per hour/km is found using high-frequency mobility data as input.
“The daily energy requirement of an electric minibus taxi is reliant on the operation of the vehicle, such as the total distance travelled during the day and whether the vehicle operates in an urban or inter-city scenario. As such, average energy requirements range from 56 to 215 kW h/day for taxis travelling 81 to 296 km/day.”
As part of his research, Giliomee developed a software tool to simulate the charging of a minibus fleet. The simulation indicated a peak grid-load of 12kW per taxi and grid-drawn energy of 87.4 KWh per taxi per day. Giliomee says that because daily commuters use minibus taxis predominantly during the day, there will be several charging peaks during the day, which will put enormous strain on the grid.
To reduce the electrical supply requirements, he added a solar and external battery system to the simulation. To counteract that and enable sustainable long-distance paratransit, he developed an operational plan using swappable, solar-charged battery bank trailers – a solution that saw the average peak power draw reduced by 66 percent while total grid-drawn energy was reduced by 58 percent.
Giliomee says this operational plan would increase vehicle range by 120 percent, reduce average recharging downtime by 74 percent, and reduce CO2 emissions by 80 percent. “There are still obstacles to overcome in the pursuit of electrifying paratransit in SSA, but I believe the methodologies and results presented in my thesis could lay the foundation for future research and electric minibus taxi implementation in SSA.”
Giliomee started his two-year graduation programme at JLR in September 2023 and will undergo a series of six-month rotations within Jaguar Land Rover’s Project Engineering Division. “For the second 6-month placement of my JLR Graduate Programme, I was honoured to join Jaguar TCS Racing during their debut Formula E Teams’ and Manufacturers’ World Championship title wins,” said Giliomee. “Learning from such a world-class group of engineers this early in my career has been a dream come true.”
“SU’s Faculty of Engineering consistently delivers a high calibre of engineering students, and I am accustomed to that standard. However, what Johan has achieved is truly phenomenal. It was an incredible privilege to supervise him, given his abundant energy and laser focus. His work has been foundational in establishing the electromobility research group,” said Booysen.
Photo: Proud grandfather, Prof Jan Giliomee and Dr Johan Giliomee.
(Photographer: Stefan Els)
