Vector has 10 rapid chargers and several more slow chargers spread out across Auckland. These have been growing since 2016 as a way for Vector to assess grid demand and take several learnings. As EVs have grown in New Zealand, Vector's free EV chargers have become very popular - especially with EV Rideshares, Taxis, and bargain hunters. There's almost always queues at most times of the day at "rapid chargers", resulting in constant usage and free power being delivered.
The shareholders of Vector end up footing this bill, and given Entrust is the primary shareholder, that means the households of Central Auckland are subsidising the cost of providing free charging. I wanted to understand how big of a cost this could be, so did some back of the napkin maths with some assumptions:
Assumptions:
- The chargers are used non-stop between 6am and 12am, which seems to be about accurate given the popularity of these chargers, the queues, and the very short interval between disconnection and reconnection of EVs. This is essentially a 75% utilisation rate over a 24hr period.
- Each charging station has 2 chargers, so with 10 locations, there's 20 chargers.
- We use the cost of power, rather than the typical 80c per kw rate charged. This is approximately 4c per kw at the wholesale cost of power. However, typical residental power rates will be about 20c give or take. For this, I will use 15c per kw, as this considers the scale of Vector while acknowledging operating cost. This also indicates the "opportunity cost".
- Each port can deliver 50kwh of power, though realistically is around 46kwh, which is what we'll use.
- kilowatt per hour * cost per kilowatt gives us the running cost per hour. 46 * 0.15 = $6.9
- Number of chargers * running cost per hour gives us the total running cost per hour for all the chargers. 20 * $6.9 = $138.00
- Utilisation hours * total running cost. 18 * $138 = $2,484.00