Infrastructure considerations

Guidance on battery electric bus charging infrastructure for both depot charging and opportunity charging. Covers a range of considerations to inform infrastructure development such as charging time, charging strategies, charger location, depot layout AC versus DC chargers and converters, connector type, grid capacity, DERMS, electricity supply resilience, types of charger connections, top-down vs bottom-up pantographs and a case study in Wellington.

Take care in procuring buses and charging infrastructure to ensure compatibility between batteries and charging equipment as there are different types of batteries suited to different charging strategies. For instance, not all batteries are designed for fast charging so ‘fast-charging compatibility’ may need to be explicitly specified in vehicle procurement if you plan to use fast charging infrastructure.

Note that Standards New Zealand PAS 6010:2021 provides a best practice guide for public and commercial electric vehicle charging with many of the same principles also applying to battery electric buses. We recommend that you read this in conjunction with this guidance.

Standards New Zealand PAS 6010:2021 – Electric vehicle (EV) chargers for commercial applications(external link)

Note that the Low Emission Bus Working Group CCS2 Plug Type Standard Recommendation report also identifies the following safety requirements:

1. Where a supply lead is intended to be used outdoors or in a damp location, it should be selected with a degree of protection of at least IPX4 in accordance with IEC 60529.
2. Vehicle supply adaptors (electrical vehicle adaptors) should only be used if specifically intended and supplied by the vehicle manufacturer or by the EVSE manufacturer for that purpose.
3. Electric vehicle adaptors should comply with the requirements of IEC 61851:2017. The adaptors shall be marked to indicate any specific conditions of use allowed by the manufacturer.

The report also notes specifications and standards which are captured in:

PTDG: Introduction

Pavement strength

Consider pavement strength when designing charging points for both depot and opportunity charging locations. This is because buses will need to park in these locations for periods of time to access the charger which, due to the weight of the vehicles, can cause high stress on the ground surface. If this stress is not adequately designed for, surface damage such as potholes and wheel ruts may form over time.

For further guidance on pavement design at high stress locations, see:  

PTDG: Corridor inspections and maintenance requirements