I read the story on the estimation of the fuel savings of an electric car. Can you apply similar logic to my case? I drive a new Hyundai Tucson PHEV. It is very suitable for carrying equipment to deal with my wife’s mobility issue. I do only about 4,500km per annum. Because of the mobility issue, we get a refund of VAT on all petrol used. No such refund is available for electricity used in charging a car.
Because of our circumstances, we spend a lot of time at home each day, using quite a bit of daytime electricity. When one avails of a discounted night rate for electricity, the daytime rate is increased to compensate. In such circumstances, availing of night rates for electricity would have the effect of increasing our overall cost of electricity. So in estimating any saving in our case, I think we must use a rate which is similar to the daytime rate.
I understand that the cost of installing a charging point at my house is typically €1,500. It seems to me that it would take quite a few years to recover that cost through savings. I also understand that the cost of installing an outdoor 13-amp plug is about €250. I could use it to charge the battery on my present Tucson to give me about 50km on each charging, but even that is difficult to justify. From TC, Co Dublin
Yes, this could well be one of the cases where going electric actually wouldn’t save you money. In fact, it could end up costing you, but it depends very much on the way in which you use your Hyundai Tucson.
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The Tucson plug-in hybrid (PHEV), as you note, has an electric range of up to 50km – actually that’s 60km on the official figures, and in our experience it’ll manage about 40km in day-to-day use, depending, of course, upon weather, driving conditions, and your driving style.
The average of 4,500km per year breaks down to just 12.3km per day, so on average you should only need to charge the Tucson up every three days, even in a worst-case scenario when it comes to electric consumption.
In terms of fuel use, this is hugely dependent on the way you drive and, crucially, charge your Tucson. According to the official WLTP fuel economy test, the Tucson uses only 1.2 litres of petrol per 100km. But of course that’s a bit of a fiction, and based on the way plug-in hybrids come off as far more efficient in the WLTP laboratory testing conditions than they do in real-world use.
You’d have to be charging up the hybrid battery every day and doing all but a tiny handful of your driving on electric power alone to match that figure.
If you could do that, then at current fuel prices (correct on the day of writing) you’d have to spend around €102 per year on fuel, assuming a pump price of €1.90 for unleaded.
Of course, as you point out, you can get the VAT back on your petrol which should reduce the price to around €1.55 per litre, which would give you an annual bill of €83.70.
So, could you save any money by switching to electric? Probably not, no, but let’s at least break down the figures.
To cover the same distance in an equivalent electric car, which we could take as being a Hyundai Ioniq 5, you’ll most likely see an average energy consumption of around 17kWh/100km. You might actually manage slightly better than that if you’re not doing much in the way of motorway miles, but let’s take 17kWh/100km as a reasonable assumption for average energy use.
The Ioniq 5 offers a claimed range of 570km on the WLTP test, and should be able to manage 500km in real-world use, there or thereabouts. Which means that you’d only need to fully charge the battery nine times each year, in theory.
As a benchmark, Electric Ireland’s current cheapest day rate for electricity is 32c per kWh, so nine full charges of an 84 kWh battery at 32c per kWh comes out at €242. So no, you wouldn’t save any money. In fact, you’d be spending three times as much compared to your Tucson at its most possibly economical.
But the Tucson can’t really manage to do that kind of fuel economy in real-world driving. Going by our experience, a PHEV of that sort, with minimal charging of its big hybrid battery, will burn fuel at around 8.0 litres per 100km. So that means your 4,500km each year are potentially costing you €558 a year, so there’s a potentially large saving to be made by going electric.
[ What can I do if I suspect the VRT applied to my camper van is wrong?Opens in new window ]
Of course, that saving is based purely on usage, which means we’re ignoring the cost of – as you pointed out – the installation of a charging point at home (€1,500) and the cost of trading in to buy an electric car of similar size to the Tucson, all of which are going to tip the balance back towards petrol power.
Possibly the best idea here is to actually get that €250 outdoor socket from which you can charge up your Tucson’s hybrid battery. As you say, a night rate is no good to you as that pushes up the pricing for your daytime rate, which is the one you use more, so let’s stick with the standard 32c per kWh rate.
The 13.8kWh battery will cost you €4 each time you need to fully charge it, and at an average of 50km per charge, you’ll need to charge it 90 times throughout the year, which adds up to €360. Which is potentially a significant saving over our (in fairness, assumed) 8.0 litres per 100km fuel consumption rate of driving the Tucson around without charging it. You’d just about make back the cost of the outdoor socket within a year in that case.
