External batteries as a solution to the energy requirements for an electric mini-bus taxi fleet in South Africa

It is 9am on a workday morning and 100 electric mini-bus taxis (eMBTs) retreat to the Stellenbosch taxi rank after rush hour. In preparation for the afternoon trips, they all need to recharge their depleted batteries. Charging at a fair rate of 22kW, these 100 taxis add 2 200kW of demand to an already crippled grid. Blowing up this number to a national scale creates unimaginable issues, which we simply cannot solve as consumers. Alternative methods of energy supply to the eMBTs are thus needed.

The reality we are facing is that optimal charging times for the grid and EVs does not align. As the interference of the operation of a MBT needs to be minimized, the use external batteries are suggested to bridge the ‘optimal charging time’ barrier. By eliminating grid-to-vehicle charging, we can control the load put on the grid, whilst still ensuring sufficient power is available to the taxis at their optimal charging time.

Two solutions are proposed: stationary – and swappable batteries. In both scenarios the use of second-life batteries is investigated.

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