Posted by: Paul Bruce cyclechallenge | April 28, 2016

Trolleys are part of the solution

Infratil has signed a US$30m deal with Wrightspeed to supply an electric powertrain technology for its public transport business through NZ Bus.

NZ Bus recently announced that their Wellington trolley buses were going to be converted to “electric powered” vehicles. Green supporters will be out Morris dancing to celebrate…. You would think! However, all is not as it seems.

SSL Trolley Bus (a) 050216The electric “Wrightspeed” motors being installed in individual wheels, will be powered through the day by a gas turbine. What does this mean? This means we would no longer have zero emission trolleys, but a hybrid bus using a fossil fuel battery charger. European transport planners who are reconfiguring diesel and hybrids buses to zero emission trolleys or light rail would be scratching their heads.

New Zealand has traditionally been regarded as a leader in green technology, but this step backwards with respect to converting trolleys to hybrid buses, is not what we want.

We can understand NZ Bus trialing the power-train technology on a trolley bus chassis, but in order to continue to be zero emission, they should still utilize grid electricity through overhead lines and rapid charging technologies. It certainly would be great to see a NZBus trial as a test-bed for a range of associated technologies – such as auto pantograph fast charging systems, or bus stop in-ground induction charging systems

However, NZ Bus and Greater Wellington Regional Council (GWRC) needs to understand that Trolleys are absolutely part of the solution, and not be party to the destruction of the electric power supply, and the recently renewed overhead wiring. The current fleet of 57 dual rear axle trolley buses, owned by NZBus, started work in 2007/2008 with new low floor chassis. So they have at least 10 to 15 years of service life remaining, and this is confirmed by NZ Bus’s decision to utilise some chassis for the Wrightspeed powertrain.

There are many technical aspects still to be explained if the NZBus story is not just a PR sham. Gas turbine generators generally emit more CO2 emissions than comparatively sized diesel engines, but emission savings can be achieved by having a smaller power turbine running against a constant load – the battery-charging generator. I hope the vehicle design facilitates the turbine being stopped to allow battery-only operating through the centre of the city. Also we need to maximise the ‘plug-in’ charging opportunities from New Zealand’s renewable electricity network – this will be essential to achieve our greenhouse gas reduction targets.

The use of self contained bus electric routes in Wellington will also depend on Greater Wellington Regional Council requiring hybrid electric and/or battery electric vehicles in the bus network as an outcome of its contractual framework. New bus route tender documents are to be approved by GWRC on June 29th, with the decision on successful tenders expected sometime before the end of this year. The tender documents are based on the already approved Public Transport Plan, but must now be modified to ensure continued operation of the existing trolley “all-electric” trolleybus fleet.

If trolleys were removed completely, it would be the biggest setback for public transport since the light rail system was taken out fifty years ago. Three independent German universities have completed studies that predict that trolleys and light rail will remain the most cost effective form of electric public transport for 30 or 40 years.

European cities are steadily converting bus routes to trolleybus public transport. Transport authorities have found that complete public transport systems cannot easily convert to fully battery-operated systems, and there is a significant problem with battery life and consequential waste disposal.

Seattle, San Francisco, Mexico, and west European cities Salzburg, Linz, Luzern, Arnhem, Eberswalde and Bratislava are all purchasing new trolley buses.

Turkey has mandated trolley bus systems for smaller cities under 100,000 inhabitants, and modern light rail in the bigger cities. The Chinese Government has also mandated “all-electric” vehicles in major cities. Trolley buses are a part of the process and cities such as Beijing are replacing diesel and experimental battery buses with new trolleys. Guangzhou is undertaking trolleybus continuous network expansion. Shanghai, after deciding to remove trolleys, realised their error and are re-opening trolleybus lines.

Other electric transport modes fit well alongside trolleys – light rail, rapid transit, suburban rail, battery buses – sharing power supply infrastructure and facilities. Zurich, Lyon, San Francisco and Seattle use light rail as the ‘spine’ of their public transport systems, and then use trolleybuses for the heavy secondary routes.   Battery bus systems are being developed for the shorter suburban feeder routes.

Oxford University Head of the Energy and Power Group, Professor Malcolm McCulloch, has looked at the Wellington trolleybus network and sees it as having excellent potential. He says that they are a valuable public asset and dismisses criticism of them as being subject to political interpretation as obsolete technology. His advice is to validate the alternatives (i.e. hybrids-electric and battery-electric), while continuing to operate the trolley buses. When reconfigured with modern (lithium ion) batteries, trolleys would be able to run longer distances “off line”, providing more flexibility. Automatic re-attachment devices would further minimise delays.

An urgent review of the GWRC business case is needed. A new business case should concentrate on the east/west route as a base case for trolleys, then explore add-on options, and include the cost of modifications to increase the reliability of the power supply network.

Wellington has big renewable electricity resources within its boundaries, and can easily aim for a 100% electric transport system, which is not only the smart choice, but an ethical one, because of the reduction of greenhouse emissions.

300 cities around the world manage trolley bus networks successfully and there is no reason why Wellington should not re-emerge to operate its system as well as other cities.

The trolleys have good capacity and would be ideal for the proposed Karori/Seatoun trunk route. Keeping the all-electric trolleys and the overhead wires on that route, at least, would be a step towards a fully “all-electric” fleet in the future. Hybrid electric buses can only be as good as trolleys in terms of CO2 elimination if there is frequent recharging at stops, not using on-board fossil-fuelled ‘top-ups’. The trolleybus power supply provides that – but that infrastructure is exactly what the GWRC has decided to remove.

I call on NZ Bus to confirm that they will operate the Wrightspeed powertrain “fuel agnostic gas turbines” on CNG, as this will avoid the major source of cancer-causing airborne soot particles and noxious gases from diesel fuels, which are so dangerous to health. The diesel particulates are associated with lung cancer and other lung disease, and contribute to heart disease and strokes.   If NZ Bus then converts diesels to the Wrightspeed power-train technology, Wellington city does indeed move forward.

Cr Paul Bruce is a Greater Wellington Regional Councillor

Paul Bruce

Greater Wellington Regional Councillor

Note that this article is the opinion of the writer, and does not represent the view of GWRC




  1. […] Source: Trolleys are part of the solution […]

  2. Faced with a fleet of newish buses that GWRC is determined will become unoperable next year, Infratil has been innovative and identified a way of reusing those assets, and good on them. (I suspect that losing all their South Auckland business has helped to concentrate the mind, too – they won’t want a repeat of that.) Their PR is carefully phrased to maximise it’s greenness, exactly as you’d expect a savvy company to do, with a hi-tech Kiwi connection as an added bonus. And converting diesels to hybrids is actually a move in the right direction. So in the circumstances it’s all good on the Infratil front.

    But it’s particularly good news for GWRC and its trolley removal plans, getting rid of any concern about the wastefulness of scrapping newish trolleys, and ensuring that there will be no trolleys left to operate the Karori-Seatoun route (which, of course, they have already allocated to Infratil), effectively removing the only credible trolley retention scenario.

    So Wellington’s transport planning continues to stagger on…

  3. Hi Mike, I don’t think we should give up! The electric powertrain can be used together with the overhead power supply, probably with a cost saving.

    • As Winston Churchill is reputed to have said, never, ever, give up.

      But it always pays to have a devil’s advocate lurking somewhere, because that helps give an appreciation of what has to be overcome.

      Part of my submission to WCC’s low-carbon plan is that the trolleybus infrastructure (not mentioned by WCC!) should be retained until we’re in more sensible times (after the local body elections, perhaps…).

      As an aside, other low-carbon WCC transport assets not worthy of a mention in the plan were the cable car and the pedestrian network (much of which is concealed behind WCC “no exit” signs) – no mention of encouraging walking.

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