I’ve been told that if you buy an electric vehicle (EV) and plug it into the grid to charge it you’re only reducing your vehicle emissions by about 5%. The problem being that most of our grid energy still comes from coal. If you really want your EV to mean something you either need to purchase Green Power or charge it with solar panels.
I’m currently in the market for a solar system for home, so I’m keen to know what I should do if I also want to charge an EV? I know I can either buy the additional panels with the original installation, or size the inverter / micro-inverters to allow plug-ons later. But what size should I get and how long will it take to pay back?
By my table-cloth calculations I should allow for a 1.5kW solar system which, when running my EV from the solar energy, will pay itself off in 2.5 years and give me surplus energy. Nice. [I’ve included my calcs below in case you’re curious].
So, what we really need to see when buying an electric vehicle is a packaged deal including solar panels and charging kit for the home and even for the office. The road price of EVs in Australia is still high but also still falling, and I’d hope the $2,500 cost of a PV system is something the car dealer could even throw in as a sweetener… that’s what I’ll be asking for : )
Calculations [I didn’t fail maths at school, but I didn’t top the charts either, so feel free to check]
- A Nissan Leaf runs at roughly 18kWh/100km – equivalent to approx. 1.8-2.3L/100km
- Current electricity cost daytime =25.0c/kWh [I’m saying daytime because I want to charge the car directly from my solar panels a couple of days a week]
- I currently drive about 150km/week in total and spend around $30/week on fuel
- So to run the Leaf I need 27kWh of electricity to charge [18kWh/100 x 150]; let’s say 30kWh. 30kWh costs me $7.50/week to run the car [30kWh x $0.25].
- This saves me $23/week or $1196/annum on petrol, based on today’s petrol price of $1.49/L. do you think that will rise or fall in the future?!
- My solar panel/s need to give the car around 4.28kWh/day [30kWh/7]. To deliver 4.28kWh/day I’ll need say a 1.1kW system, but typical packages come in 1.0kW or 1.5kW.
- A 1.5kW system is currently averaging around $2,500 installed [good quality and warranties], including RECs. If I’m simply upsizing the system I’m buying for the house then the return for the EV panels is even better, given that the inverter and install costs are shared.