New Auckland harbour crossing

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#3459578 7-Feb-2026 19:41

If we look at what charging input's needed to add a 2 km of range to a bus...
The busway stops are 1-5 km apart and 7 km to get over the bridge.

I believe a sedan-sized EV needs about 100 kWh (of battery) to do 1000 km - so that's 0.1 kWh per km.
I'd assume a bus would need 10-20 times that - so maybe 2 kWh /km ?

At 350 kW transfer rate, 4 kWh (2 km x 2 kWh/km) would take about 40+ seconds - plus time to connect, ramp up & down and then to disconnect.
A minute wouldn't seem long - if passengers were getting on/off.

To get power for 7 km (eg: the bridge), would take about 2.5 minutes - that might feel a bit tedious.

Whereas 15 minutes at the end of a run would be good for 40+ km (only one set of overheads).
And the single charging site would be hugely easier to build & maintain.

RunningMan

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#3459583 7-Feb-2026 20:51

@pdh - Bjorn Nyland did a bus test. https://youtu.be/ovJVNSRAoWw?si=SPLI53V7VjWuhqIm&t=1260

Combination of urban and motorway it used 695 Wh/km, so roughly a 1/3 of what you estimated. Even for a larger bus, perhaps half of your estimate would be about right.

pdh

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#3459600 8-Feb-2026 02:41

> Even for a larger bus, perhaps half of your estimate would be about right.

Well, I'd like to see some real-world figures with passengers included.
I know that EV pickup trucks are not fond of towing trailers - it halves their range.
So adding in 6+ tons of passengers will be worse than an empty bus.

Anyone know how well Auckland EV buses do ?
You would think that AT would be praising their performance widely - if they are pleased...

RunningMan

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#3459606 8-Feb-2026 08:10

On stop start journeys like a bus, the weight will have less impact due to regen braking - what is used to accelerate is gained when braking at the next stop. A lot of the drag from towing is the trailer aerodynamics, which remain unchanged when the weight is within the bus.

pdh

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#3459749 8-Feb-2026 13:26

Regen breaking is nice - but there are significant losses.
Good point about trailer aero - but (PU+trailer) decreased mileage is seen in urban (ie: low-speed) use as well.

I believe Auckland's ev buses are 12 m (double-decker) and 13 or 13.5 m (single-decker).
I can find lots of data on their expected (hoped-for) range - but none on what they actually achieve.
Take that as you will.

OK - I fell back on the dreaded Ai to locate some real-world ev bus data:
(I like Perplexity because it gives me sources which I can verify.)

From a Dutch study (100 buses over 10 months), they got 1.15 kWh/km for 12m and 1.63 for 18m.
(www.sustainable-bus.com)

Given that Holland is a bit flatter than Auckland is, but probably gets a bit colder - I'd say swings and roundabouts.
Their data is likely quite attributable to us.
I's suggest that their 18m single-decker is closer to our 12m double-decker in weight if not aero.

Perplexity comes up with another dozen studies - from Bonn, Knoxville, etc.
All in a range of 1-2.5 - depending on length, load, temperature & hilliness.

So I don't think I was all that pessimistic in my guesstimate...

RunningMan

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#3459763 8-Feb-2026 15:44

pdh:[snip] Regen breaking is nice -

No, it's not. You'd be requesting a repair if it did.

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#3462691 18-Feb-2026 16:41

"“There’s a range of decisions to be made about the funding of that project. It is in theory a project that should be able to pay for itself.” Brown said today that big decisions about a second harbour crossing or tolling should be made together with Auckland, and not by government agencies working in secret."

https://www.nzherald.co.nz/nz/auckland/wayne-brown-says-9-auckland-harbour-bridge-toll-unacceptable-to-aucklanders/CHT2GM2OEZBPLDPNUCC3HGV7N4/

Auckland City and the government working together in secret instead? Edit: I'm just too irritated by the whole traffic cones tag team thing to be posting.

ezbee

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#3462698 18-Feb-2026 17:02

Weren't we all supposed to be driving these? How about a bus sized version.

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SaltyNZ

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#3462749 18-Feb-2026 17:50

RunningMan:

pdh:[snip] Regen breaking is nice -

No, it's not. You'd be requesting a repair if it did.

I see whatcha did there

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bfginger

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#3482289 19-Apr-2026 20:41

From looking at this problem, the entry to the south side of a new bridge from Point Chevalier could be solved by shaving about 5% off the top of the Chamberlain Golf Course, shifting the motorway slightly southward and running a tunnel from there under the suburb to the landing of the causeway at the top of Meola Reef Reserve.

The major problem however would be on the North Shore side where they'd have to dump as many as 100,000 cars a day onto a limited main road which is already not fit for purpose. I don't see how this is a feasibly resolvable problem.

Superficially, the option with the path of least resistance would be to do another crossing directly adjacent and parallel to the existing bridge and make use of the existing motorway lead-ins on both shores.

SaltyNZ

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#3482393 20-Apr-2026 10:00

bfginger:

From looking at this problem, the entry to the south side of a new bridge from Point Chevalier could be solved by shaving about 5% off the top of the Chamberlain Golf Course, shifting the motorway slightly southward and running a tunnel from there under the suburb to the landing of the causeway at the top of Meola Reef Reserve.

The major problem however would be on the North Shore side where they'd have to dump as many as 100,000 cars a day onto a limited main road which is already not fit for purpose. I don't see how this is a feasibly resolvable problem.

Superficially, the option with the path of least resistance would be to do another crossing directly adjacent and parallel to the existing bridge and make use of the existing motorway lead-ins on both shores.

The new crossing shouldn't be primarily for cars in the first place. It should be focused on PT. Preferably light rail.

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wellygary

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#3482398 20-Apr-2026 10:22

pdh:

Regen breaking is nice - but there are significant losses.
Good point about trailer aero - but (PU+trailer) decreased mileage is seen in urban (ie: low-speed) use as well.

I believe Auckland's ev buses are 12 m (double-decker) and 13 or 13.5 m (single-decker).
I can find lots of data on their expected (hoped-for) range - but none on what they actually achieve.
Take that as you will.

OK - I fell back on the dreaded Ai to locate some real-world ev bus data:
(I like Perplexity because it gives me sources which I can verify.)

From a Dutch study (100 buses over 10 months), they got 1.15 kWh/km for 12m and 1.63 for 18m.
(www.sustainable-bus.com)

Given that Holland is a bit flatter than Auckland is, but probably gets a bit colder - I'd say swings and roundabouts.
Their data is likely quite attributable to us.
I's suggest that their 18m single-decker is closer to our 12m double-decker in weight if not aero.

Perplexity comes up with another dozen studies - from Bonn, Knoxville, etc.
All in a range of 1-2.5 - depending on length, load, temperature & hilliness.

So I don't think I was all that pessimistic in my guesstimate...

AT estimate their overall EV bus fleet is 1.07kwh/km,

(Table 31 page 68)

https://environment.govt.nz/assets/publications/Measuring-Emissions-2024/Measuring-emissions_Detailed-guide_2024_ME1829.pdf

pdh

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Ultimate Geek
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#3482532 20-Apr-2026 14:11

Does anyone find it shocking that they use estimates of electricity consumption (1.07) to derive 'exact' figures for electricity consumption. In case in needs to be said, you are supposed to do it the other way round...
Measure the fuel in - and the distance travelled - then calculate the fuel per km.
If that's not a blatant book-cooking / get-the-answer-you'd-like process, then I've never seen one !

They also do it for the Diesel buses as well, with an equally straight face.
Do they not record how much fuel they put into their vehicles ?

gzt

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#3482544 20-Apr-2026 14:38

It's easy to agree with your statement. The purpose of the data was estimating emissions or calculation for emissions saved. The data underlying the example was provided by Auckland Transport. It's unclear what AT might have based that on. In any case, it is what they had to work with.

I see electric busses in Utrecht have heated seats. That might consume a few watts in wintertime ; ).

Edit: Anyway.. this is the wrong topic for a detailed discussion of electric busses..

quickymart

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#3491434 16-May-2026 11:02

https://www.nzherald.co.nz/nz/bridge-or-tunnel-aucklands-second-harbour-crossing-decision-looms-the-front-page/EHPNQ5SESVE6VOV3KQ7BRFDBWQ/

The Auckland Harbour Bridge turns 67 this month, and the need for the city to have a second harbour crossing is becoming even more glaringly obvious.

In-depth assessments on the bridge’s condition over the years have shaped the long-term maintenance programme currently in place.

But the need to intensify efforts is nigh. As the bridge continues to age, it requires more frequent and complex maintenance to keep it safe.

So no more kicking the can down the road, by the looks of it.

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