Solar energy potential for electric taxis in South Africa

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South Africa’s minibus taxi fleet going all-electric could require up to 10% of the current national grid generation for recharging.

Considering the abundant sunshine in South Africa, modelling of a grid-connected solar PV charging system suggests that half a tennis court of capacity would meet the energy needs of a taxi on an average day.

Based on an average distance of 228km and stopping times ranging from 8 to 11 hours – a proxy for charging opportunities – the mean energy demand of a taxi is estimated at 213kWh/day, resulting in an average efficiency of 0.93kWh/km.

The study, published in the journal Energy for Sustainable Development, was intended to assess the potential for electrification of the country’s estimated 285,000 minibus taxi industry.

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The energy supplied per surface area of PV to offset the charging load of a taxi while stopping ranged from 0.38 to 0.9kWh/m2 per day, with the average taxi able to directly utilise up to 80% of the installed PV generation capacity during normal stops.

“Given South Africa’s abundant sunlight, we have an excellent chance of harnessing this renewable energy source to power electric vehicles,” says Thinus Booysen, professor in the Department of Electrical and Electronic Engineering at Stellenbosch University, who led the research.

“A charger of around 32kW would be required. This means that the total fleet of South Africa’s minibus taxis would use around 10% of the daily national energy generation. This may not seem like a lot, but it would cover approximately 70% of the country’s commuter trips, while incentivising investment into renewable energy infrastructure.”

The study, which should have applicability to other countries with similar minibus taxi fleets, was based on GPS tracking and spatio-temporal data of taxis travelling between towns approximately 20km apart in the Western Cape.

The maximum daily impact that a taxi would have on the power grid was calculated to be approximately 500kWh per day, although for 75% of the time the impact would be less than 300kWh per day.

The study envisages that solar PV is installed at taxi ranks and informal stopping areas.

Other findings are that demand peaks would occur from 06h00 to 09h00 and 17h00 to 18h00 with potential for charging, particularly around midday from solar energy and from midnight to 04h30in the morning probably from grid power or potentially stored solar energy if storage (not considered in the study) is added to the infrastructure.