Electric vehicles - impacts on the power system

 

The Commission is currently working on the demand forecast of a high electric vehicle uptake in New Zealand and the impact that this could have on generation development. The electric vehicle demand forecast is intended to be incorporated in the Generation Expansion Model (GEM)

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In order to estimate the electricity demand of EVs, we first looked at the number of electric vehicle uptake from 2007 to 2040. (This analysis focused on personally owned light vehicles and did not include commercial light vehiclse, buses, trucks or motorcycles.) Plug-in hybrid EV specifications, i.e. range (km) and efficiency (Wh/km), were applied to calculate total demand and a regional allocation.

 

We considered two (somewhat extreme) options for recharging these vehicles; either they can only be charged during the night (the “smart” scenario) or the load can be spread over the entire 24 hours of the day (the “unregulated” scenario). Evidently the unregulated scenario will increase the morning and evening peak demand on the national grid, resulting in a need for extra generation capacity. The results are then expressed in terms of Load Duration Curves (LDC) and finally split in load blocks for use in GEM.

 

Figure 1. PHEVs forecast demand (red) and national total electricity demand at grid exit point (blue) for the “smart” scenario.	Figure 2. Load Duration Curves (LDC) of the demand on the national grid + PHEVs demand (dash red) and the demand on the national grid only (solid blue) for the “smart” scenario.

 

This model is still in development and requires further work. For instance the Ministry of Transport is going to provide more accurate data on trip durations, which will be used to refine the estimated distribution of the number of kilometres travelled in electrical mode. We also intend to do further work on recharging scenarios.

 

Presentation on plug-in hybrid electric vehicles pdf [630 KB]

for the Ministry of Transport. 

 

Contact Erwan Hemery

for any further information on the Commission's work on electric vehicles.