I’ve a four-year-old Renault Zoe. I’m getting 383km when charging at home. The car does short journeys. I charge once every eight days. I don’t yet have a smart meter so could you tell me roughly how much it costs per charge. I usually don’t let the battery go down below 25 per cent – two utility companies cannot answer this question. – A Hunston from Co Dublin
Well, first off, congratulations on an excellent choice of EV – in all the fuss and hubbub surrounding the new Renault 5, the Zoe seems to have been forgotten like yesterday’s milk. That’s an unfair fate for an EV with decent range (395km was the official WLTP figure), a decent driving experience, and, in the later versions, a high-quality cabin.
Anyway, we’re drifting from the point here, and working out how much you’re paying to run your Zoe is a pretty simple bit of maths, although as you haven’t told us precisely what electricity rate you’re paying, we’re going to have to make one or two educated guesses.
Let’s start with the battery. The Zoe, certainly a four-year-old one, came with a 52kWh battery, and that’s the usable capacity. If you say you’re charging it once it hits 25 per cent capacity, and topping it up to 100 per cent (I’m assuming you do as you say you’re getting 383km on a charge, which sounds like a full charge to me), then that means you’re charging the battery with 39kWh of energy each time.
RM Block
I’m going to use the current Electric Ireland tariffs as our baseline for how much each charge costs. If you’re with another electricity provider, then the cost may well be different, but it’ll be accurate within a certain bandwidth. If you want a precise, personalised figure, just get in touch with your full electricity tariff details.
So on the ‘Time Of Use Tariff’ day rate of 25.92c per kWh, that means that each 25-100 per cent top-up of your Zoe will cost you €10.10. Charging at night, though, slashes that cost, so if you can plug your Zoe in between the hours of 11pm and 8am (and you can set the car to charge specifically during those hours either by using the controller app for your charger, or through the Zoe’s own systems) then the rate falls to 13.62c per kWh, and so now each charge costs you just €5.31.
On that tariff, there is a Peak-Time cost of 27.65c per kWh, but that only lasts for two hours between 5pm and 7pm, so on a home charger the maximum you’d be able to charge in that time would be 14.8kWh worth, slightly more than one-quarter of your battery capacity, which would cost you €4.09.
So, let’s assume that you’re being smart and doing all your charging at night, which means that if you’re charging every eight days, then you’re charging just four times per month (it’s 3.8 times in 31 days to be exact, but let’s round up) which means that your Zoe is costing you just €21.24 in ‘fuel’ each month. Or €254.88 per year. Which is pretty staggeringly cheap, especially if you’re comparing it to even a very frugal petrol-engined car.
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The petrol-engined equivalent of the Zoe is, of course, the Clio, and even in basic form, with the 1-litre 90hp turbo petrol engine, you’d be doing very well to hit an average fuel economy of 5.0 litres per 100km.
So, how much would you have to spend on petrol to cover an equivalent mileage? Well, you say you’re getting 383km out of each charge, but charging up once the battery hits 25 per cent, which means on average you’re covering 288km between charges. At a rounded-up average of four charges per month, you’re covering 1,152km every month. Which means you’re covering a little less than the average daily mileage of 49km, incidentally – according to the Central Statistics Office.
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However, to do 1,152km each month in a notional Renault Clio, you’d have to use 57.6 litres of petrol, which would cost you €101.95 at the current average per-litre pump price of €1.77. That would equate to an average annual fuel bill of €1,223.40.
Which, even without breaking out my calculator watch, is a lot more than you’re paying to ‘fuel’ your Zoe. In fact, on the basis of these calculations, you’re saving €1,000 a year on fuel (although of course, you may well be facing higher repayment costs for the Zoe, depending on the deal you got, and it’s quite possible that your insurance may well be costing you more).
