Out with the old, in with the new

From the Red Line
Published in
10 min readFeb 10, 2024


The LTA will buy up to 420 electric buses from BYD and Zhongtong. Blaze it.

All these are proven models, so we’re not buying anything new or bespoke. We can look to ComfortDelgro and their NUS and NTU shuttle bus operations to see how these will work, in addition to the LTA trials being held. The university shuttle bus systems even have three doors, so there’s that.

However, only 360 vehicles are confirmed. The other 60 vehicles are available as options, though unlike the CRL trains which have extension prospects justifying their eventual purchase, it remains to be seen if the options will be exercised.

Cut and fill

The press release material is quite vague on what kind of charging strategy will be adopted for these vehicles. While some other observers may jump to conclusions, I daresay this remains an open question, considering that the first batches of charging systems will be installed in Sengkang West, Gali Batu, and East Coast. The latter two have access to opportunity charging systems at Bukit Panjang and Bedok interchanges respectively, and could easily reuse these facilities. Options also exist to install chargers at upcoming bus hubs in Pasir Ris and Punggol too, so it remains to be seen what form those chargers take.

Similarly, there is some time between the first deregistrations, expected in October, and the planned introduction of electric bus service in December — though I won’t be surprised if issues mean that their introduction gets pushed back to 2025, widening this gap even more. These may be proven bus models, but there may still be concerns with the charging system infrastructure and whether the bus depots are even ready to welcome them in the first place. The timeline still feels uncomfortably tight to me, and too many things can go wrong in the meantime, especially as all the bus depots to receive charging facilities are still under construction. Just look at how long it took to introduce the Linkker electric bus.

It also remains to be seen what kind of routes these vehicles will be used on. The Choa Chu Kang-Bukit Panjang package can build on the experience it already has in operating electric vehicles. This first production batch can be deployed on routes that have seen electric bus operations before such as 61 (and which shifts!), 172, 184, and 983. But electric bus operations will be quite new in the east, and there will have to be a transition phase while they figure out what routes are good for electric bus deployments and what are not.

And this may not even be existing routes. Remember that Hong Kong’s bus quotas exist partially due to concerns from engine noise and diesel exhaust pollution —issues electric vehicles do not have. I suspect this was a large selling point in how BYD managed to push C6 minibuses to Service 825, with 825 likely being the first route to operate electric vehicles on a non-trial basis. Electric vehicles can expand public transport coverage by increasing the acceptability of running bus routes in quieter residential estates without noisy diesel engines, and service hours would be useful to enable these and drive public transport usage.

It may also be an open question on whether Seletar, Loyang, and Bulim depots, all of which already have chargers under the pilot introduction, will receive more electric vehicles — and whether they are enough for the planned deployments.

Clarke’s first law?

Over in Hong Kong, the venerable Mr. Lyndon Rees, founder of Citybus, is not a fan of the electric buses there. Things are apparently that bad there that buses were parked at terminals and used as air-conditioned waiting rooms.

However, I suspect both KMB and the Hong Kong government are having a bad case of Clarke’s first law. They were on the electric vehicles bandwagon long before us, with KMB purchasing 10 BYD K9s that were delivered in 2017, and another batch of fast-charging supercapacitor buses that were also delivered in 2017 and are now being sold off. In comparison, ours only entered service in 2020–2021, so there may have been technological improvements available to us that weren’t available to them.

Similarly, they have also more recently brought in B12A single deckers and B12D double deckers, which appear to be mostly used on short-distance urban routes within Kowloon and feeders in the New Territories. There are exceptions, like 52X/62X between Tuen Mun and Mong Kok and cross-harbour service 110, but these appear to be few and far between.

The 95% fleet utilization achieved by Mr. Rees’ Citybus may yet be possible with advancements in vehicle technology in Hong Kong, but when even the new B12s are used chiefly on slow start-stop local services within Hong Kong’s urban areas, instead of the long-distance, high-speed intertown express services Hong Kong is known for, seems to say otherwise. For now.

Likewise, Singapore is able to benefit from advancements in technology in reducing cost and hopefully improving vehicle performance. Economies of scale also help somewhat. Here’s how far we’ve come.

  • Back in 2018, the overall cost of introduction for 60 electric vehicles and corresponding charging facilities was $50.64 million = roughly $833,333 per vehicle.
  • Of course, this includes 10 Yutong double deckers, and while double deckers cost more, is outweighed by the lower per-unit cost of the Linkkers. A better comparison is the cost of 20 BYD K9s, which at $17.25 million have a unit price of around $862,500.
  • In late 2023, we are paying $212 million in total for 360 vehicles and charging facilities, working out to a cost of ~$588,888 per vehicle including charging facilities
  • This is similar to the cost of the Volvo B5LH hybrid bus, which cost $28.5 million for 50 vehicles in 2017 — stated to be “double” the cost of a regular single-deck bus.

In conclusion, even after accounting for inflation, waiting a few years has managed to bring down the cost of electrification. It also remains to be seen if battery chemistries have improved — BYD, for one, appears to have increased battery capacities by 40% between the K9 and the CDG-spec B12 units.

Or did they just add more batteries? Nothing wrong with that per se, but more batteries add more weight, which may cause issues with road maintenance as heavier vehicles wear roads out faster. The Yutong E12DD is supposedly two tonnes heavier than a typical diesel double decker, and it carries lesser passengers. Heavily trafficked bus lanes and stops may bear the worst of this, and with Singapore’s traffic density, the lanes themselves, not just the bus stops, may require rebuilding to stronger concrete surfaces compared to asphalt.

Improved chemistries allowing more energy charge per kilogram of weight may thus be the better option in overall costs, allowing road maintenance to produce savings as well, or at least avoid additional spending. Which of these have happened? And will they happen fast enough?

One to many

In this light, the data provided by Mr. Rees must be examined in Singapore as well. However, we also have the great unknown in that capital planning is divorced from operations, since the LTA controls vehicle purchases but bus operators decide how many they actually need; resulting in the “storage bus” phenomenon of excess vehicles not needed by operations.

It is possible that traditional practices in SBS Transit — and to a lesser extent SMRT — may provide a far more forgiving environment for electric bus operations. SBST has the largest deployment of electric buses, they have all 20 BYD K9s, and are also evaluating the BYD B12 demonstrator to gain in-service experience.

One thing to consider, though, will be how to manage a significant ramp-up in the EV population, especially at existing depots like Seletar, Loyang, and Bulim, where it appears that charging infrastructure will not be upgraded. We will retire over 900 buses by the end of 2026, and currently announced plans only provide for replacing less than half that. If we really are going to replace 900 buses over the next three years, even more money will have to be spent to move things faster than they are now. New bus depots in Lorong Halus, Pasir Panjang, and Simpang, will only be ready by 2029 at the earliest.

There will be competition for charging bandwidth, both in terms of physical charging equipment, as well as the availability of electricity supply at the times vehicles need to be charged. Already programmes exist to encourage users to reduce electricity consumption during peak periods in the day — not just residential users like you and I, but also commercial users which bus depots are likely considered under.

These savings are significant, especially for commercial users. We’re talking about close to 40% savings at the High Tension Large 22kV level, which is likely to be what will be used by bus depots. compared to the typical Low Tension supplies used by households.

middle column = existing charge, right column = existing charge with GST (source SP Services)

What this means is that it can be cheaper to run a bus throughout the day and charge only at night; compared to running in peak hours and charging during the midday. Consequently, one may find that night periods are best for charging electric vehicles, intensifying the competition for charging facilities. Dedicated night shifts may even be needed just to drive buses around the depot to maximise the use of charging facilities during the cheaper off peak. Reducing charging facility demand may also be possible by scheduling peak-hour use buses in a way that they may only need to be charged every other day or something.

Singapore also doesn’t have the treacherous terrain of Hong Kong, where additional power is needed to haul heavy double deckers up mountain roads and viaduct/tunnel ramps. That is, unless you count South Buona Vista Road, though judging by the current announced locations of electric bus charging facilities, it is unlikely that electric buses will be plying South Buona Vista Road anytime soon.

The 2027 problem

There is also another reason to tread carefully and wait for technology development.

The LTA may be able to take heart in the fact that Hong Kong-spec Enviro500EVs appear to be able to deliver higher battery capacity without compromising on cabin space, with the same 82 seats as our MAN A95 diesel vehicles. That means it’s possible, and it’s a matter of time that other companies catch up. But if the future for Singapore is three door vehicles, including double deckers, that may not be enough.

This blog has said repeatedly that we must ask ourselves just what we value out of our bus network. As double deckers come up for replacement from 2027 onwards, starting with the Volvo B9TL, will it be possible to purchase replacement electric double deckers with three doors and two staircases? Or will it be possible to obtain competitive bids even just for regular electric double deckers, if more than Alexander Dennis have the battery density to enable the use of more cabin space? This is a big number — 1 in 2 buses here are high capacity, compared to other jurisdictions which may have much more 12m buses than high capacity ones.

Or might they be forced to reconsider articulated vehicles, allowing the batteries to go on the roof? Articulated buses achieve their high passenger capacities by packing standing passengers in. Traffic Police regulations for vehicles calculates licensed standing capacity at a whopping 0.15 square metres per passenger = ~6.7 passengers per square metre. Even trains aren’t specified to such densities, with typical datasheets only going up to 6 passengers per square metre.

We don’t even use that in planning — at 250 passengers per MRT train car, numbers used by planners are closer to 4.5 passengers per square metre. More comfortable bus rides may mean 30% less standing passengers. This gap may be unacceptable with today’s diesel technology (thus the risk of passengers not moving to the upper deck being worth taking), but the gap may close as electric batteries take up more cabin space inside a double decker, eating up passenger capacity.

More realistic passenger counts

We could also end up waiting it out even more. Should battery technology not mature sufficiently and quickly enough to provide a good enough option for high capacity buses by 2027, we may end up replacing double deckers with single deckers, creating a net decrease in capacity for the bus network. With the amount of money thrown into rail expansion, the MRT must then step up to provide the journeys long distance bus travel used to.

Of course, it always comes down to this, and we can’t run away from this fact. The expansion of the rail network, if played well, can allow for double deckers to be reshuffled around, which can buy us more time, provided of course the rail lines open on time. This is within the LTA’s control as integrated planner and manager for all public transport operations.

Apart from things that can be done with remaining TEL and CCL6 openings, the JRL also provides extra capacity to take on long-distance passengers from key trunk routes in the west like 179, 180, 199, and 249. Further down the road, the CRL will also be a replacement for some of the major north-to-east TPE routes, as well as the excessively high bus demand to the Clementi Road academic belt.

The long and short of it is, this is only the end of the beginning. We will have a lot more problems as we start to scale. They are not without solutions, but the only obstacles are political — not funding, but that money cannot solve every problem. The music will stop, and tradeoffs will need to be made.

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From the Red Line

Sometimes I am who I am, but sometimes I am not who I am not.