BYD ADL partnership delivers the Enviro400EV

The long-awaited battery electric BYD ADL Enviro400EV double-decker will enter service in London soon. It’s the latest product from a partnership that has growth in mind – both in the UK and beyond

Partners BYD and Alexander Dennis (ADL) have revealed the Enviro400EV battery electric double-decker, which they say will deliver a range of 150 miles on a single charge and an overall passenger capacity of 83.

The first 37 Enviro400EVs are for London operator Metroline. It will place them into service on route 43 within the coming months.

Several have already been delivered from ADL’s Scarborough factory on chassis produced by BYD in China, although underframe production will later move to Hungary.

Following them will be 32 Enviro400EVs for Stagecoach Manchester. They will differ from the Metroline examples in being low height, the first time that the Enviro400 City body will be assembled in such form. They will be single door; additionally, they will lack a glazed staircase.

BYD’s chassis utilises technology developed for the Enviro200EV single-decker.

The Enviro400EV platform is significantly different to that utilised beneath five all-BYD proof of concept electric double-deckers that entered service with Metroline in 2015, having a more advanced driveline and better weight distribution.

The BYD ADL partnership has taken orders for 276 zero-emission buses. 160 of them are in service, including two in New Zealand. The Enviro200EV range will grow soon with the first 10.2m examples about to enter service, and they will be followed by a 9.6m variant.

That is further evidence of the joint venture’s growing dominance of the UK electric bus market. The two manufacturers claim already to have over 70% of it, with an aspiration to increase that share in the future despite strong competition. The double-decker segment will be key to that.

Advanced technology

In the Enviro400EV, 382kW/h of energy is stored at the rear and in two separate areas within the wheelbase. Positioning the batteries to optimise weight distribution was important. On the earlier BYD double-deckers that was not done so effectively, impacting their capacity. The Enviro400EV has 47kW/h more stored energy than the earlier buses while weighing significantly less.

BYD’s standard electric bus drive axle is used in the Enviro400EV, albeit with twin 150kW hub motors. They represent a significant uplift in power over the Enviro200EV, which comes with a dual 90kW rating. ADL says that increase is because of the Enviro400EV’s greater weight. To Transport for London specification, it tips the scales at 13,294kg unladen and has an GVW of 19,200kg.

The latter will increase in due course, says Project Manager Phil Kershaw. The front axle is designed for a maximum weight of 8,000kg, but it is currently certified to bear 7,700kg. ADL is working to take advantage of the full permitted tolerance, which will allow the Enviro400EV to achieve the maximum 19,500kg GVW permitted on two axles. The electric double-decker is standardised at a length of 10.88m and, in full-height form, at 4.32m tall.

Passenger pleaser

To keep the saloons at a comfortable temperature, heat pump technology has been adopted.

The Hispacold system’s efficiency accounts for an additional 20 miles of range over a comparable bus with conventional electric heating, and it also delivers up to 21kW of interior cooling capacity.

ADL and BYD have committed to zero-emission heating in the Enviro400EV.

Some variants of the Enviro200EV are available with a diesel-fired unit, and a hybrid diesel-electric heater that includes geofencing capability is an option, although none are yet in service with geofencing enabled.

ADL is proud of its work to maximise the seating capacity on the lower deck of the Enviro400EV. Immediately behind the driver is a double seat, while on the nearside a European style ‘mother and baby’ pair is behind the front door.

Further back, the arrangement differs from conventional double-deckers in that all seats are forward facing; there are no backwards-facing pairs over the wheel arches. That is likely because the rear axle is set further back than on a diesel bus.

Legroom in the rear row is cramped as a result, although that is the only area of criticism from a passenger’s perspective. Because of the set-back drive axle, single-door Enviro400EVs will have an emergency exit at the centre on the offside.

Upstairs, there are no such legroom issues. ADL’s signature glazed rear dome is fitted, although the pillars are more solid than on a diesel bus. That’s because they act as part of the ducting for blown air that vents via the coving panel throughout the length of the saloon. The glazing still admits a tremendous amount of natural light, however.

The bus shown last week does not have USB charging points, but they will be retrofitted prior to delivery. Other members of the batch for Metroline will receive them on the production line.

Although to do so would introduce a range consideration because of increased weight, it will be possible to fit ADL’s SmartSeat, with its amenity console. Coupled with other options – which include “pretty much everything” that is available on a diesel – that opens the door to corporate duties where environmental considerations ride high on the agenda.

32 Enviro400EVs to be supplied to Stagecoach Manchester later this year

Smart energy

The Enviro400EV uses BYD’s second-generation battery system with liquid cooling. The package comes with a five-year warranty as standard that can be extended to 10 years at extra cost.

Both manufacturers are reluctant to publish energy consumption per mile figures, but BYD will work with customers to ensure that route schedules are analysed to provide estimates of both usage and charging requirements when battery degradation, heating and necessary reserves as considered.

Even so, when the amount of energy storage onboard and the claimed range are considered, the resulting calculation suggests a more conservative view of consumption than those made by some other manufacturers.

That tallies with the two parties’ view of under-promising and over-delivering.

Charging is undertaken using a BYD-supplied free-standing unit. It is compact and allows up to three rows of buses to be charged from a single ‘island’; that is an important consideration for operators whose depots are cramped.

The three-phase unit delivers a maximum of 80kW of charging power, allowing a full replenishment to take place within four-and-a-half hours. ‘Smart charging’ is available, which minimises the peak load on the grid connection and allows cost efficiencies in the associated infrastructure.

Short overhang behind BYD drive axle on the Enviro400EV is noticeable

Electric future?

Although ADL is spending a lot of time working with BYD on its collaborative electric bus range, zero emission is not seen by ADL as the answer to everything. Far from it, says CEO Colin Robertson. “I don’t see 100% of the bus market going that way by 2030, or even 2040,” he explains.

Even so, ADL offers an alternative emission-free double-decker in the hydrogen fuel cell Enviro400FC. It or the biogas-fuelled Enviro400CBG, built in partnership with Scania, could be better suited to some duty cycles.

“I believe that electric buses could come to represent around 25% of the UK market by 2025, and 50% within ten years, but it is difficult to make an accurate prediction.”

On fuel cell technology, he acknowledges that major progress has been made. The availability of charging infrastructure is likely to be what influences hydrogen’s uptake more than anything else.

Additionally, like more than one other leading industry figure, he points out that air quality issues could be mitigated significantly by greater adoption of Euro 6 diesel.

But those considerations are for another day. The Enviro400EV will, where the finances stack up, form a highly-acceptable product for intensive urban services. With BYD already having said that it is engaged in a programme of constant improvement for its driveline package, the newcomer undoubtedly has a bright future ahead of it.

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Colin Robertson is correct to be pragmatic about the potential for electric buses to dominate the UK market. They still cannot satisfy higher-mileage applications without a mid-day charge, which is not something that most operators have the slack to accommodate.

Where they have great merit is on urban services with a low average speed and where passenger volumes are high. On all but the most extreme of those duty cycles, 150 miles’ capacity is likely to be enough for a full day.

The reveal of the Enviro400EV is a significant moment for ADL, just as it is for the Plaxton factory at Scarborough. 69 orders from two customers have already been confirmed and it is impossible that many more will not follow.

Most notably, the second batch of Enviro400EVs will go to a provincial operator. Stagecoach Manchester received government funding towards them, but they could represent a real turning point that finally signals a serious assault on the market outside London by electric buses.