Decarbonisation
Decarbonisation refers to a transition from the current fossil fuel power sources (predominantly diesel) to zero-emission vehicles or vehicles using zero-emission power sources.
For example, decarbonisation could be achieved through the deployment of buses powered by electricity, hydrogen or other power sources that result in an equivalent reduction in greenhouse gas emissions such as bio-diesel or bio-methane.
Zero-emission vehicles refers to vehicles that emit no emissions at their tailpipe.
The Government’s commitment
The Government will:
- require only zero-emission public transport buses to be purchased by 2025
- target the decarbonisation of the public transport bus fleet by 2035, and
- support regional councils to achieve these outcomes through a $50 million fund over four years.
The Government will engage with the sector about how the $50 million fund is spent, and how barriers to decarbonisation can be overcome in the fastest, most economically efficient way.
The Government has no plans currently to require school buses contracted by the Ministry of Education, InterCity buses or private coach operators to use zero-emission buses, although all transport operators and vehicle owners are encouraged to look at ways they can reduce their own transport-related carbon footprint.
Contribution to cutting greenhouse gas emissions
The projected annual emission reduction from a zero emission bus fleet by 2035 is estimated to be between 150 thousand and 189 thousand tonnes of carbon dioxide equivalent (CO2-e).
The cumulative impact of decarbonising the fleet by 2035 is estimated to be a 3.0 to 4.5 million tonnes CO2-e reduction in emissions by 2050.
Public transport buses in the New Zealand fleet and 2035 estimates
The majority of public transport services are provided in our towns and cities. There were just over 2,600 public transport buses in operation in 2018/19 financial year. Most of these (around 80% or 2,100 buses) are operated in the three main centres of Auckland, Wellington and Christchurch.
It is estimated that there will be between 3,500 and 4,000 public transport buses by 2035.
We are confident that advances in technology over the next 15 years will enable the Government to fulfil its commitment to target the decarbonisation of the public transport bus fleet by 2035.
e-buses in the fleet
There are fewer than 40 active electric buses in the public transport fleet, although this number is set to increase rapidly throughout this year. Around 150 additional zero emission buses are expected to come into service between now and early 2023.
Zero-emission buses
Costs
The purchase price of an equivalent-size electric bus is around twice that of a diesel bus, however electric buses are cheaper to operate and maintain. The purchase price of electric buses is expected to fall significantly as the technology matures.
Where zero-emission buses are made
Zero-emission buses are manufactured or assembled in a number of countries, including in New Zealand, and a growing number of bus manufacturers are adding them to their product ranges.
Range of zero-emission buses
Public transport buses average between 100km and 150km each day. Existing battery technology is more than sufficient to support this travel distance and is only set to improve.
The electric double decker buses operating on the Number 1 route in Wellington use a fast charger at Island Bay to top up the batteries during use.
This allows these buses to have a smaller battery than would otherwise be required, reducing weight and road damage and future RUC (road user charges).
Hydrogen offers much faster recharging times than electric buses (minutes rather than hours) and offer a greater range than diesel buses.
Hydrogen buses are currently more expensive than electric buses and require new infrastructure to create and distribute the hydrogen fuel.
Operating life compared to diesel buses
There is limited experience with operating electric buses in public transport fleets and technology is improving rapidly. However, we estimate the operating life of an electric bus in the public transport fleet to be between 16 and 20 years.
According to Waka Kotahi NZ Transport Agency’s Requirements for Urban Buses, diesel buses are expected to operate in the public transport fleet for 20 years.
Type of infrastructure needed
Electric buses require charging infrastructure and extra space may be required at depots to enable the installation of chargers. New cabling to bring the power from a nearby substation to the depot may also be required.
Some e-bus designs may also incorporate in-service battery top ups (such as that used for buses on the Island Bay route in Wellington). This is not expected to be common, though it may be necessary on some longer routes.
At present, electric buses have heavier axle loads than diesel versions largely due to the additional weight of the batteries and their axle configuration.
Although the market for e-buses is developing quickly, most e-buses only have a standard two-axle format while most large buses in New Zealand incorporate a third axle at the rear to reduce road damage. As demand for zero-emission buses grow, we anticipate the supply of three-axle e-buses to increase, which will lessen the wear on our roads.
Safety and environmental concerns
Zero-emission buses contribute to improved air quality and lower noise pollution. That benefits passengers, other road users and those who live in urban areas, especially those who live close to bus routes.
Although they are significantly quieter than diesel buses, they are not silent. We will continue to monitor the safety of electric buses.
Old batteries from electric buses
Several New Zealand businesses are already accepting batteries from electric vehicles for recycling and re-purposing.
Batteries still have a residual value once they can no longer be used to run electric vehicles. Work is taking place in New Zealand (including by the Energy Efficiency and Conservation Authority) and internationally to consider all the ways that batteries can be refurbished, repurposed or recycled.
Retiring diesel buses
Some diesel buses may be retired early, but there may also be options to decarbonise these vehicles by running them on zero-emission fuel sources. However, most will be replaced with zero-emission buses when they come to the end of their life in the public transport fleet.
At present most retired public transport buses are used as dedicated school buses, and the expectation is that this will still happen. But school buses generally travel far less than public transport buses, so their carbon footprint is lower.
Other low emissions options, such as biofuels, are expected to be available to assist in reducing carbon emissions from these older diesel buses.
Road User Charges (RUC) exemption for e-buses
E-buses are currently exempt from paying RUC. The RUC exemption can only be extended if legislation is changed.
Government is considering a range of changes to the road user charging legislation to address low carbon fuels, including the possibility of extending the current RUC exemption. Announcements on this will be made separately.
Reducing transport emissions
This is just one part of the Government’s plans to decarbonise the transport sector.
Officials are currently developing a Transport Emissions Action Plan. This will be our plan for how New Zealand could reduce its transport emissions and will be the basis of the transport section in the Government’s Emissions Reduction Plan for the 2022–25 emissions budget.
Climate change — emissions work programme