Abstract
The transport sector is pivotal to socio-economic development and remains a major contributor
to greenhouse gas (GHG) emissions and air pollution. In South Africa, road transport
accounted for 10.8% of the nation’s GHG emissions in 2020. Battery electric buses (BEBs)
offer a sustainable alternative to diesel buses, providing reduced emissions, lower operational
costs, and environmental benefits. However, their adoption is limited by high initial investment
costs, constrained range, and performance challenges related to varying terrains, particularly
in urban areas like Johannesburg, characterised by diverse route profiles and significant
elevation changes This study evaluates the feasibility of deploying BEBs in Johannesburg’s
Metrobus fleet using a techno-economic assessment methodology. Seven representative
routes were assessed based on technical parameters including elevation, gradient, speed,
acceleration, idle time, energy consumption, and energy savings, and economic parameters
including fuel costs, total cost of ownership (TCO), and TCO reduction. A Multi-Criteria
Decision-Making (MCDM) framework was utilised to rank the routes.
Routes with lower elevation gains and gradients, such as Route 412 (Gandhi to Witpoortjie)
and Route 49 (Liefde vrede to Gandhi), demonstrated superior energy efficiency, with energy
consumption of 1.35 kWh/km and 1.38 kWh/km, respectively. These routes also exhibited
reduced idle times and lower energy consumption, making them ideal for BEB deployment. In
contrast, routes with steeper gradients, including Route 45 (Maritz Brothers to Braamfontein)
at 1.79 kWh/km and Route 420A (Sunninghill to Westgate) at 1.71 kWh/km, experienced
higher energy demands due to frequent elevation changes and extended idle times. These
routes necessitate larger battery capacities of 200 kWh and 180 kWh, respectively, despite
their shorter ranges. Route 262 (Hillbrow to Pomona), with energy consumption of 1.36
kWh/km, demonstrated high operational efficiency, even with its hilly profile, and represents
another optimal candidate for BEB adoption.
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Economic analysis highlighted significant TCO reductions for BEBs compared to diesel buses,
primarily due to lower fuel and maintenance costs. For example, Route 412 (Gandhi to
Witpoortjie) exhibited a TCO of R61.8/km for BEBs, representing a 23.33% reduction relative
to the R80.6/km for diesel buses. Similarly, Route 262 (Hillbrow to Pomona) achieved the
highest TCO reduction of 29.6%. Even on challenging routes, such as Route 45 (Maritz
Brothers to Braamfontein) and Route 420A (Sunninghill to Westgate), TCO reductions of
3.16% and 3.11% were observed, respectively. Despite higher initial vehicle and infrastructure
acquisition costs, BEBs demonstrated lower fuel and maintenance expenses. For example,
the TCO fuelling and DEF costs on Route 412 (Gandhi to Witpoortjie) were R24.5/km for
BEBs, compared to R51.8/km for diesel buses.
This research underscores the importance of route-specific deployment strategies. Flatter
routes such as 412 (Gandhi to Witpoortjie) and 262 (Hillbrow to Pomona) should be prioritised
for initial BEB implementation, while challenging routes require strategic interventions such as
enhanced battery capacities, intermediate charging stations, and optimised schedules. By
employing a techno-economic assessment methodology, this study provides a robust
framework to facilitate the transition to BEBs, aligning with Johannesburg’s sustainable
transport objectives.