Electric vehicles are getting more and more popular as an alternative to internal combustion engines. Instead of stopping at the petrol/gas station the EV owner has a range of options in which to choose and effectively there are 3 x modes of charging:
*( electric vehicle supply equipment)
Most of the portable chargers available are single phase with varying outputs and there are some that can use three phase AC.
The single phase units have capacities up to 15A plug with a larger than normal earth pin but there are heavier duty options around. Some have a screw fitting, the more industrial ones but you will have a socket that matches.
The 15A units are versatile in that they fit into standard power points but you will need a 15A to 10A converter. The issue is that the charge time on these units is long with a max of 3.5 kW output.
Same as portable units except they are housed in a purpose built enclosure mounted on a wall and is wired directly to the house switchboard.
Come in single and three phase from 7.2 kW and 22 kW. Cables can be built in or portable with pros and cons with both approaches.
For more information I thoroughly recommend an article in Renew issue 156 by Lance Turner that goes into great detail concerning the different methods of charging, the pros and cons, potential network interference in the future and great buyers guide
All energy usage should be looked at from the perspective of a T.E.M.S approach ( Total Energy Management Strategy) and in the examples presented we make certain assumptions concerning the EV’s battery capacity, the owner’s drive profile, domestic charging access, solar contribution and more.
Will be looking a a range of options from full peak grid charging to a solar off peak charging strategy
So before getting stuck into it we have to make certain assumptions which are:
In this situation the customers tops up over a few nights after solar production hours and turns off charging before the off peak tariff kicks in:
*never full discharges all the battery capacity
In this situation the customers tops up just during off peak periods, either after 10 pm and before 7 am Monday - Friday, on the weekend or a combination of both:
In this situation the customers tops up just during peak and off peak with a 50:50 split:
Now the only time the customer can utilise his domestic solar system is on the weekends but there are few assumptions that have to be made to make this example realistic:
So, per week is $9.24, per year $ 480.48, after 10 years assuming 2% increase in electricity per year will cost $5,261.12
Now the ideal scenario is for the EV’s battery to be charged completely from a renewable energy source but, unless the owner has access to onsite charging, which indeed may be the case, the direct contribution from solar will be limited to the weekends and this assumes that they won't be driving the car at all!
There is another option and that is a correctly sized solar system in conjunction with an energy storage solution. Let’s assume that the customer has a larger solar system and a Tesla Powerwall and intends to charge from it.
In this option the customer’s EV will be charged directly from three sources and in no particular order:
So we will have to make some assumptions in regards to the contribution of each.
We know that we can directly charge on the weekend and contribute 6 hours/week to the EV battery load. This leaves 19 hours of contribution from the other two sources:
Total cost per week is $1.45, per year this is $76 and after 10 years assuming 2% increase in electricity per year will cost $825
As more and more consumers start purchasing EV’s strategies will need to be developed in regards to usage and also charging regimes. Relying on purely peak grid power will not only cost the owner but put undue stress on a power system that is already fatigued.
Using a combination of solar, cheap grid power and storage results in the cheapest yearly costs but we haven’t factored in the purchase price of these renewable energy systems.
A prudent approach involves a cost benefit analysis of all approaches tempered by financial realities, drive profiles and access to off peak grid and renewable energy sources and storage options.
Be warned; EV’s are here and they are not going away!
If you’d like to see more of what Greenwood Solutions get up to in the real world of renewable energy, solar, battery storage and grid protection check out the following pages:
https://www.greenwoodsolutions.com.au/industry
https://www.greenwoodsolutions.com.au/commercial
https://www.greenwoodsolutions.com.au/commercial/customer-stories
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