by Dave Rhodes
As a bus driver in Wellington, New Zealand, I’ve observed the local authorities have been changing the way the bus services operate quite significantly over the past decade.
With the last remaining trolley bus service in Oceania, for some extraordinary reason, the local (very green) city council decided to terminate the trolley bus service to be replaced by diesel (initially) and then battery-electric buses.
The last trolley bus ran in late October 2017.
Andrew Surgenor, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons
Many questioned the logic behind the closure and it became a topic for the newly elected left-wing labour/green government to consider – who eventually refused to intervene.
Diesels, both single and double-decker dominated initially, but over these intervening years the various bus companies have invested in battery powered vehicles.
I drive both diesel and electric and must say that I still by far prefer the diesel version simply because of their versatility.
Range is an issue, and range anxiety is very real. Driving a diesel and setting out for the day with a full tank of fuel means never having to worry. With an EV, after 60Km (around 40 miles), a recharge is really needed. Having to recharge the bus takes time out of my rest break – I lose at least 10 minutes that I would otherwise spend relaxing with a cuppa and stretching my legs on a fine day.
Different EV’s have different charging characteristics. A good fast-charge vehicle takes around 500amps at 675volts. Around 10 minutes is all it takes to bring one of these up to full charge. Others can only slow charge at around 40amps and take hours!
Currently, the city fathers are busy creating a new charging facility in the centre of town at the railway/bus interchange. When it is completed, at least there will be a chance to top up a fast-charge EV. Not so lucky with the slower ones.
Queuing for a charge is inevitable, so again stress increases when you need to take a bus out on time to meet the rather tight schedules.
One thing I have noted over this time is the ageing of the batteries. Many of the EV buses are 4 years or older, and have already had battery replacements. Some are on their second replacement set. Heaven knows what the cost is for a bank of batteries – both fiscal and environmental. I drove a 2018 model the other day and it had far greater range than I was used to – asked a mechanic and “yes” new batteries!
Of course it’s not just a single battery module as in many EV cars, but rather battery modules stashed wherever they can be squeezed into
Very recently, a new “Airport Express” service has been introduced running exclusively EV single-deck buses. Built in China by Zhengzhou Yutong Bus Co., Ltd, these distinctive buses in pale blue livery operate every 20 minutes between Wellington Station and the Airport.
Apparently, this service is proving very popular with over 100,000 passengers carried since its inception on 1st July, but that’s not hard since the previous diesel-powered “Airport Flyer” was withdrawn 2 years ago. During the intervening period, no public transport serviced Wellington’s International Airport – passengers both to and from had to rely on taxis, shuttles or personal transport options. Not hard then for a bus with no meaningful competition.
photo courtesy of stuff.co.nz
Have EV buses been beneficial? Depends on your point of view. From a driver view-point I give them a thumbs down. The extra stress placed on drivers adds to an already stressful job.
Wellington has some unusual and rather unique driving conditions, with many roads designed solely for horse and cart winding their way up through very hilly suburbs. Squeezing a large bus through these streets is bad enough – keeping eyes glued on the state of charge at the same time does not help.
Sorry to any eco-conscious souls out there, but give me plain olde-fashioned diesel very time.
Don’t think EV busses make a lot of sense: weight, range, battery life, fire hazard…
But am very sure that full hybrid city busses make a lot of sense even with their hybrid price premium. Engine off at idle and regenerative braking, when city busses make a lot of stops. Downsize diesel to maintain 35-40mph plus AC w/o hybrid assist, so major fuel savings (about a third). Use the electric machine torque for acceleration from stop. City busses need a full brake job about every 25k miles, but with regen braking, the hybrid brake service interval is about 100k miles. Plus almost weight comparable as the downsized diesel offsets the extra traction battery weight. Plus, unlike EV battery going from full to mostly discharged during a bus ‘day’, hybrid bus battery floats between at worst about 45-55% charge and will easily last the life of a city bus, about 12 years.
Broward County Transit Authority (Fort Lauderdale, FL plus it’s suburbs and exurbs (like Weston, which was Everglades fringe once upon a time) started buying only hybrid city busses (made in Europe) about 5 years ago because the savings are compelling. Almost half the fleet now. No problems reported at all even tho some of the exurb highway bus routes are partly 55mph rather than 35 or 40.
Stop and go driving is where regenerative brakes are least effective.
Please provide some data for that assertion. The evidence I have is to the contrary, as is the logic. Regen braking means the electric machine is slowing the vehicle while placing charge back into the hybrid battery. So no brake pads are involved until near full stop.
Simple, the power generated by a generator goes down as the speed of the rotor goes down. IE, the slower the wheel turns, the less power generated. Less power generated, less breaking power,
You can compensate for this by increasing the current through the stator, however there is a limit to how much current can be pumped through a wire, and the increased power decreases the efficiency of the generator.
To put it another way, the power output from a generator is proportional to the current through the stator and the speed of the rotor. The slower the rotor turns, the less power is being generated. So as the car slows, the braking power of regen brakes goes down.
PS, why all the down votes. I’m stating a simple fact.
For a further example, if the rotor isn’t moving at all, you will get no power from your generator. If you start the rotor moving a very slow rate, you aren’t going to immediately jump to full power.
Furthermore, if the power being put into the stator exceeds the power being generated by the generator, you will have regen braking, but power will be coming out of the battery, not being put into it.
If you are slowing from 60 to zero, your regen brakes will be able to recover energy. If you are slowing from 5 to zero, then your regen brakes will actually cost you energy.
Regenerative braking is not all it’s cracked up to be. You probably only regain about 1/3 of power. Say you spend 6% SOC climbing a hill – typical in Wellington. Coming back you can expect to only regain 2% by regen braking….
I found this interesting electric hybrid add-on for single axle semi trucks:
https://youtu.be/XSB3WaeolcU
I have seen an article discussing hydraulic accumulators on Garbage trucks that can save up to the eighty percent of the stopping energy and they return it as the truck accelerates. Purely mechanical with no need for batteries and a one year pay back on Garbage trucks. I would think the same system would work on busses.
And it can be retrofitted to existing vehicles.
After driving a bus for 1 hour, how much time is needed for recharging?
Not needed really. After 4 or 5 hours, 10-15 minutes fast charge is all that’s required. Otherwise overnight slow charge,
I can only imagine a battery fire kn one of those busses.
Paris did not have to imagine. They lost several all at once, fortunately overnight charging while not in service. Rather spectacular next day internet images, since partly Google suppressed.
What suppression by google ? Its got multiple sites and reports
eg https://www.bloomberg.com/news/articles/2022-04-29/paris-suspends-use-of-bollore-electric-buses-after-second-fire
What part of the word partly are you having trouble with?
Wow , suspending the use of 150 electric buses. Maybe Bolloré is the french word for bollox.
Sorry for you mate,
Hard to beat the convenience, reliability and range of diesel. CNG is also a poor substitute. You are speaking from a driver’s perspective. The taxpayer gets stuck with the bills. Purchase price, maintenance, service life, etc. All of it outrageously expensive.
I drive both diesel and electric and must say that I still by far prefer the diesel version simply because of their versatility.
Range is an issue, and range anxiety is very real. Driving a diesel and setting out for the day with a full tank of fuel means never having to worry. With an EV, after 60Km (around 40 miles), a recharge is really needed. Having to recharge the bus takes time out of my rest break – I lose at least 10 minutes that I would otherwise spend relaxing with a cuppa and stretching my legs on a fine day.
greens create problems when none exist.
A slight modification to be more accurate.
Greens imagine problems where none exist. Then they imagine ‘solutions’ that then create real problems.
Adding color: Greens imagine AGW is a problem based on faulty climate models, when all observations say it isn’t. So they then imagine and incentivize green renewable solutions that create real problems because of intermittency and lack of grid inertia.
An addendum: Greens are really stupid, reality impaired Greta types.
A great article from an operator’s point of view. Too few of the pie-in-the-sky ideas from the greenies get to be truth tested in real life. Thanks Dave.
Even worse , the trolley bus fleet of 49 was relatively new ( from around 2008) and it was haphazardly thought they could be converted to full battery power ( they have smaller batteries for moving short distances)
Amoung the reasons was consultants wanted to redesign the routes to change the way passengers used the buses – more hubs and less traditional longer direct routes, which was a big failure as of course changing buses meant the schedules ‘didnt/couldnt’ align
“Bus schedule” has always been an oxymoron.
500 volts and 675 amps?????
That works out to 337,500 watts.
Forget active cooling, you’d have to imbed the bus in dry ice to keep those batteries cool.
Make that 500 amps and 675 volts. Doesn’t change the answer though.
I hope the author answers questions, because I have two of them.
Thanks in advance.
This suggests that the buses consume 3.5 kWh per mile. Would that be about right? 21 tonnes is a bit more than 46,000 pounds, or so say the internet calculators. Are you certain that this the weight with passengers? I’m drilling down because Tesla has said that its 82,000 pound semi truck will consume about 1.75 kWh per mile. I don’t believe Tesla, and am checking that claim this way.
True that hill climbing cuts fuel economy, so I have to find a way to factor that in.
21 Tonnes is the maximum weight allowed for these buses. The unladen weight is around 15 Tonnes. With Wellington being so hilly, I would have thought 3.5KWh was being very conservative. Regenerative braking is not very effective, and I note climbing a typical hill consumes around 250amps (at 650volts say), so that’s around 162.5KW. Using on average 20% SOC to travel 40Km return, 3 full return journeys is all that can be reasonably expected before needing a recharge (our allowance is 30% SOC)
There are some hybrids on the (free) loop bus I sometimes use. Back in the day there was a ‘Green’ bus (literally actually, it was green) that was apparently fully solar.
And by fully solar what they really meant was that the council who ran it calculated they had enough solar on enough buildings to cover the recharging.
It was a horrible bus. Couldn’t hold a charge. If you were waiting for a late bus it was an easy bet that it was the Green Bus that finally turned up. The 19 seat diesels that also supported that route ran on time. The internal layout was horrible with lots of dead space and minimal seats. The council purchased this with much press and then it quietly disappeared after a couple of years after the batteries packed up and there was no replacements.
Then it came back and was still rubbish.
The power available was so low after a couple of hours driving that when going uphill it was impossible to run the bus and the air con at the same time.
Horrible bus.
So the council had the bus moved into the management of the company who ran the other bus networks. We got hybrids on same route. The plus side they run on time. On the minus side they are very uncomfortable. The transmission kicks in and out of the hybrid modes, especially when breaking and as a passenger you are jerked around.
The only ‘real’ advantage is that they are not burning diesel in the urban areas, so all the nasty smells are Not In My Backyard.
That charge rate is a tough life for a battery. It will kill the cycle life. Life deteriorates on most chemistries when charged faster than 2 hour rate. 10 minutes is horrendous. It is a wonder the batteries do not burn up.
Also a few buses pulling 350kW each on recharge is industrial level power.
It is useful to get this sort of perspective on the coming revolution in transport. It appears more a dabble doomed to failure than a revolution.
Those were my thoughts..
.
OK, 350kW would work and be safe, for a Li-Ion battery with a capacity of 350kWh. That means a charge rate of 1C
That size of battery sort of stacks up with a 40 mile range – it means ~9kWh per mile or the equivalent of (roughly) one litre of diesel per mile.
Is that what you get with a heavy vehicle doing stop/start urban driving?
(I always understood that UK trucks (45 tonne artics) get about 2 miles out of one litre cruising at 50mph)
But the figure of “10 minutes to full” is, and has to be wrong – it’s implying a charge rate of 6C
Li-ions are the fastest chargers you’ll get presently and if you charge them faster than 2C they ***will*** blow up
Looking at the ‘charger display’ and where its talking about UnitMinVol and UnitMaxVol, those are the charge characteristics for Lithium Ion cells.
LiFePO4 figures would be around 3.3Volts, Lead acid around 2.1Volts per cell and NiCd around 1.3Volts while charging fairly hard
But the fastest chargers in that list are the LiFe cells, fastest safe charge rate for those being 0.5C
Wow!! A 700kWh LiFePO4 battery would be a beast – can I haz one please, for Christmas.
Pretty please. Pretty pretty pretty pls
(Shirley would find good use for it, she’s ‘like that’)
😀
Perhaps a little clarification,
1 We are not allowed to run a bus with less than 30% SOC
2 Before setting off, we have to ensure we have enough SOC to complete our route without dropping SOC below 30%
3 On the longer runs, we must ensure we have at least 68% SOC before we start
4 Typical charge is from around 40-50% up to full charge (98%) and takes around 10 minutes although the final few % can take too long to be bothered with so leaving with 95% is not unusual
And how many sudden and severe fires, and how many dead passengers, have to result before this worse-than-useless idea is shitcanned?
The charge starts very high, but is slowly reduced as SOC increases. The last 5% can take 5 minutes on its own as charge drops to around 50 amps. The charger stops at 98%.not 100%.
Only 1 fast charger is available currently (a new one is being constructed in the CBD) so there is only one bus pulling 350Kw at any one time.
The trolley bus service in Oceania was of course an electric service with the advantage of not dragging around a very heavy battery. The battery must weigh at least 3000 pounds, equal to carrying 20 passengers. Perhaps why they brought in diesel, hard to justify changing an electric trolley for one very expensive new one, carrying expensive to replace batteries, and using lots more electricity.
Trolley buses fed from grid far better option
Maybe not when the grid can’t keep the light on half the time because it has too much wind and sun input.
Trolley buses were mostly dropped by cities because of the easy potential failure of the transport system regarding the overhead electrical lines. The time required to plan and build the overhead lines meant very little flexibility for route changes, plus trolley power was always an issue for any street re-construction, sewer rework, and road closures for ANY reason…..ICE buses solved these logistics/planning/budgeting issues problems with diesel being the lowest cost per mile.
Theoretically battery driven buses solve these same issues too… except for battery cost and life, bus weight on roadways, and electrical infrastructure for charging at the bus barn….About 5 times the energy density and materials that cost the same per kg. as aluminum ICE engine blocks would solve the problem /s
Maybe it’s different where you are?
Around here, when you spot junction boxes carrying that kind of voltage and amperage, they’re securely locked, making it impossible for ordinary people to contact live circuits.
Worse, that voltage is in DC current and far more likely to kill.
Not to add stress to your job, but what kind of heavy insulative shoes and clothing do you wear to protect yourself when charging these vehicles? Are there days when the floor or you are wet when charging these vehicles?
The fast charge is via a pantograph system, so way out of reach. Slow charge is just the same style as say a Tesla. And yes, it rains a lot in Wellington
Other issues I’ve heard about: as mentioned, their weight make them useless as soon
as you have slanted terrain. Some cities had to dispatch them to lines where all the bus-stations were at the same level. The fire hazard is also something to worry about. I saw a video of one burning in Paris and it wasn’t pretty. Another one burning among other busses which it also set on fire. Someday, insurance companies won’t put up with this anymore.
Here in the states, most levels of government do not purchase insurance.
Damages caused by things under their jurisdiction are covered by the government; usually white washing the involved government officials.
Which disguises government inadequacy or incompetence.
Insurance companies may pay attention to damage caused, but do not include government losses in their accounts.
SNCF = French national railways => no insurance
I wish they were insured.
Well there’s not much point having treclic vehicles to save the planet if they’re rolling with coal power. So that means lots of grid firming batteries for all the planet saving unreliables and naturally the price of said batteries must be kept top secret for now-
https://reneweconomy.com.au/contract-for-worlds-most-powerful-battery-blacked-out-and-the-regulator-is-not-happy/
Otherwise the Chinese or Russians might find out what we’re up to eh lefties?
Replacing the battery on a Chevy Volt (once every ~4 years depending on usage) can run up to ~$20K USD. Given buses are used much more heavily, how long before the batteries need to be replaced and what is the approximate cost per replacement?
The answer is with technological/manufacturing advances and gigafactory economies of scale they’ve plumbed the bottom of lithium battery pricing some time ago and it’s all uphill from here with mandated/subsidised demand-
https://www.instituteforenergyresearch.org/renewable/electric-vehicle-battery-costs-soar/
In future solid state or sodium they must trust for affordable transport now..
They seem to spontaneously combust easily