Cape Town-based Golden Arrow Bus Services (GABS) is planning to introduce 60 electric buses to its fleet every year starting in 2024 until it has replaced its full fleet of 1,100 diesel-powered people haulers.
The bus operator first employed a BYD K9 electric bus in the mother city in April 2021 on a trial basis to test the feasibility of these vehicles for transporting commuters in and around the city, acquiring another unit in September 2022 which was more suited to its special operational requirements.
GABS has also been steadily reducing its carbon footprint since 2017 through the installation of grid-tied solar panels at six of its bus depots in Cape Town, currently boasting a peak generation installed capacity of 1.7MWp which has helped it to become a net electricity generator.
A big success
After two years of testing both a 37 and 65-seater electric bus along major commuter routes in Cape Town, GABS’s pilot project has proved to be highly successful.
Initially, the buses completed 7,000km of testing without passengers with the weight of the maximum number of occupants modelled using sandbags to check whether the vehicles would be able to traverse the mountainous terrains on which they are required to work.
Next, the operator introduced passengers to the electric buses in June 2021 for another 50,000km of testing the public transport vehicles’ safety and range.
The real-life trials showed that the electric BYD buses were able to operate on the steepest inclines in Cape Town, most notably Hospital Bend on the M3.
Passengers also reported a quiet, comfortable ride with improved air quality at bus stops due to the reduction in fumes.
Aerial view and elevation of Hospital Bend (M3), Cape Town
In addition to the satisfactory driving performance, GABS found that it could save upwards of R657,000 per year on fuel for its diesel buses by switching to electric, as well as achieve a 50% savings in spare parts and 80% savings in oils and lubricants.
Therefore, despite the battery-powered buses being two to three times more expensive than their diesel counterparts, the cost savings will see them paying for themselves within two to eight years, according to a Green Cape case study.
The buses themselves are powered by two electric motors with a combined peak output of 300kW and 1,100Nm, connected to a 324kWh lithium-iron-phosphate battery pack.
With this setup, they offer a top speed of 100km/h, a range of 300km, and a 0-100% charging time of three hours on an 80kW DC fast-charging connector.
GABS cost-benefit analysis: diesel vs electric bus
Plans for the future
Now that GABS has shown that electric buses can work in South Africa, the operator plans to replace its entire fleet of diesel buses starting in 2024 at a rate of 60 vehicles per annum using local body manufacturers and imported chassis.
At this pace, it will take roughly 18 years to convert the fleet at an estimated annual investment of around R324 to R486 million, resulting in a minimum total investment of R5.8 billion.
This will make a significant contribution to reducing public transport-associated greenhouse gas (GHG) emissions in Cape Town considering GABS’s current diesel fleet burns over 25 million litres of diesel and emits around 67.3 tonnes of CO2 per year covering a total distance of 65 million kilometres.
Peak bus utilisation and charging potential
To accommodate the move, GABS will have to up its installed renewable energy generation capacity to between 80-100MW, up from the current 1.7MW.
It is currently considering solar carports and ground-mounted solar installations where possible to fill the gap in renewable energy that is required for its future operations.
Moreover, it will develop an electric bus charging strategy that leverages the best possible times for charging at depots in order for this to have a low impact on servicing customers.
Currently, the best times for charging are between 09h00 and 15h00 when 70% of the fleet is available, and between 21h30 and 04h00 when a maximum of 95% is available.
GABS currently has two AC chargers and one DC charger at its depot for charging, with future scenarios possibly involving the placing of DC fast chargers at certain bus stops to enable en-route opportunity charging while the buses are away from the stations.
Using GABS’s model as a test bed, the City of Cape Town is also considering the procurement of electric buses for its MyCiti fleet, which consists of 374 buses, in line with the council-approved Carbon Neutral 2050 Commitment and the Climate Change Action Plan which sets out ambitions for completely electric public transport in 2050.
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