Singapore’s four contracted bus operators share a unified green livery on all their buses, and this is being progressively applied to older buses. But Go-Ahead Singapore’s buses are not just green in colour — they also sport green features.
These include “ultra-thin” solar panels on the roof of some buses, which are used to charge the buses’ batteries. “[This] effectively reduces the load on the alternator and, in turn, lowers the engine’s workload,” says Leonard Lee, managing director of Go-Ahead Singapore.
The feature was first tested in a six-month trial that began in March 2021. During the trial, two single-deck buses, each equipped with 1,000-watt solar panels, were used for bus service 15.
According to Lee, the pilot helped evaluate the effectiveness of harnessing solar energy to reduce carbon emissions and fuel consumption under Singapore’s tropical climate and traffic conditions.
The findings were encouraging, he adds, with an annual fuel savings of “3% to 4% per bus”, equivalent to approximately four tonnes of reduced carbon emissions annually.
Following the successful trial, Go-Ahead Singapore rolled out solar panels to 50 more buses by April 30, 2023.
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“We estimated that their carbon emissions will be cut by approximately 200 tonnes annually, which is equivalent to the annual carbon emissions of 43 passenger cars,” says Lee to The Edge Singapore.
That said, these buses are still running on diesel. “For Go-Ahead Singapore, installing solar panels on diesel-powered buses is one alternative to make the buses greener and more efficient, as we transition to a cleaner-energy bus fleet,” says Lee.
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Going electric
Since September 2016, Singapore has operated on a bus contracting model (BCM), which brings all public buses and related infrastructure, such as integrated transport hubs, under government ownership.
Under the BCM, the Land Transport Authority (LTA) plans bus services centrally, while public transport operators bid for the right to operate services along the bus routes. These are put up for tender as “packages”.
After winning the tender for the Loyang bus package, Go-Ahead Singapore began operations here in September 2016.
It is a subsidiary of the England-headquartered Go-Ahead Group, which was listed on the London Stock Exchange until a takeover by Australia’s Kinetic Group and Spain’s Globalvia in 2022.
In 2016, Go-Ahead Singapore collaborated with LTA on Singapore’s first electric public bus trial. The trial ran from November 2016 to May 2017, and a single electric bus was deployed on services 15, 17 and 119.
According to Lee, this allowed them to monitor the bus’ performance over varying distances and road conditions.
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During the trial period, the electric bus covered a total distance of over 15,000km. Lee says a survey of over 300 electric bus commuters garnered “overwhelmingly positive” results, with commuters and drivers praising the quiet ride and smooth acceleration.
LTA has committed to achieving a “100% cleaner-energy bus fleet” by 2040. Since March 2020, all new public bus purchases have been electric models, and by 2030, electric buses are expected to make up half of Singapore’s public bus fleet.
In November 2020, 40 electric buses were deployed for passenger service — 30 single-deck models and 10 double-deck models. In August 2021, LTA purchased 20 more single-deck electric buses from ST Engineering Mobility Services.
In November 2023, LTA announced the first large-scale award of four related contracts: two to procure a total of 360 three-door, single-deck electric buses and another two for charging systems in bus depots at Sengkang West, East Coast and Gali Batu.
Of the 360 new electric buses, 240 will come from BYD for a contract sum of about $108.1 million, while 120 will come from Cycle & Carriage Automotive, which is partnering Chinese manufacturer Zhongtong Bus to fulfil the $58.3 million contract.
The new electric buses will be “progressively deployed” from December this year to replace diesel buses that are reaching the end of their 17-year statutory lifespan.
Together with the 60 electric buses that are already plying our streets, these cleaner-energy buses will make up 7% of the current overall fleet. LTA added that the contracts include an option to buy up to 60 more electric buses if needed.
A Busways-Shell Singapore consortium was awarded the $31.3 million contract for the charging systems at the upcoming Sengkang West and East Coast bus depots, while the $14.8 million contract for charging systems at the Gali Batu bus depot was awarded to Presico Engineering.
Works at the bus depots in Sengkang West and Gali Batu are expected to be completed this year, while the bus depot in East Coast is expected to be completed in 2025.
This is just the first batch of large-scale tenders for bus electrification, according to LTA. “More tenders for electric buses and infrastructure upgrades to support their operation and maintenance will be called in the coming years.”
Given how public buses are typically kept running all day, fleets of “green” buses will go a longer way in Singapore’s sustainability journey than passenger cars that clock lower mileage.
Time to recharge
There are several key considerations to take into account when transitioning to electric buses, says Lee, who was previously the engineering director of Go-Ahead Singapore. These start with planning for electric buses to charge.
As with all electric vehicles, the charging of the electric buses would require “considerably more time” compared to the current refilling of its diesel tank, notes Lee.
Depending on the remaining “state-of-charge” of the electric batteries and the charging infrastructure speed, this could typically take several hours, he adds.
In addition, the last bus typically returns to the depot at around 1am or 2am after the last service and the first bus leaves at 4am or 5am, says Lee. “This would entail some level of planning of the bus deployment schedule to ensure that all buses are charged sufficiently for the services on the following day.”
In LTA’s August 2021 announcement, the authority mentioned the use of pantograph chargers, which are located at Bedok and Bukit Panjang Bus Interchanges.
With pantograph charging, electric buses are charged at a higher power rating of up to 450 kilowatts during their short layover time of 10 to 15 minutes at bus interchanges, according to LTA. “When activated by the bus captain, the pantograph charger mounted overhead at the designated parking lot will lower its connector.”
The November 2023 announcement, however, was scant on details. It only stated that the upcoming bus depots at Sengkang West, East Coast and Gali Batu will be equipped with “smart charging functions” to “optimise charging speeds and duration”.
Forging ahead
On charging, the Go-Ahead Group is eager to share its expertise. Lee says the group is the UK’s largest provider of electric bus services. It also operates Britain’s first all-electric bus garage in Waterloo, London.
“Go-Ahead recently completed work on one of the biggest electric charging hubs in the UK at our depot in Oxford, which features 104 charging points. The group is working closely with the Mayor of London to deliver his plans for a zero-emission bus fleet by 2034. Additionally, Go-Ahead’s newly-built electric bus garage, Northumberland Park, is the biggest overnight charging electric bus garage in Europe,” says Lee.
According to Lee, the group is piloting initiatives such as opportunity charging, which involves using a pantograph at the bus station to allow electric buses to receive a “top-up” charge during their daily operations.
In addition, the group has proven the concept of “Bus2Grid”, a system where buses can feed any surplus electricity back into the grid when they return to the depot, Lee adds.
For now, Go-Ahead Singapore continues to service its sole Loyang bus package. In August 2020, Go-Ahead Singapore received a two-year contract extension to continue operating the bus package until September 2023. In September 2022, this was further extended until September 2026.
In general, the contract for a public bus package lasts five years and can be extended with “good performance”, says Lee. “Our plan is to expand our operations by bidding for and securing additional bus packages.”
Photo: Go-Ahead Singapore
