Walking on sunshine: Pairing electric vehicles with solar energy for sustainable informal public transport in Uganda

Abstract

Minibus taxi public transport is a seemingly chaotic phenomenon in the developing cities of the Global South with unique mobility and operational characteristics. Eventually this wide-spread fleet of minibus taxis will have to transition to electric vehicles. This paper examines the impact of this inevitable evolution on a city-wide scale in Kampala, Uganda. We present a generic simulation environment to assess the grid impact and charging opportunities, given the unique paratransit mobility patterns. We used floating car data to assess the energy requirements of electric minibus taxis, which will have a knock-on effect on the region's already fragile electrical grid. We used spatio-temporal and solar photovoltaic analyses to assess the informal and formal stops that would be needed for the taxis to recharge from solar PV in the region's abundant sunshine. The results showed energy demand from a median of 224 kWh/day to a maximum of 491 kWh/day, with a median charging potential (stationary time) across taxis of 8 h/day to 12 h/day. The potential for charging from solar PV was 0.24 kWh/m^2 to 0.52 kWh/m^2. Our simulator and results will allow traffic planners and grid operators to assess and plan for looming electric vehicle roll-outs to the most-used mode of transport in Africa.