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Electric vs Petrol vs Diesel: Which Should You Buy?

Despite what some critics may tell you, electric cars are now very much a realistic transport option for some drivers.

Several car manufacturers now sell electric vehicles, and that choice is only set to expand in the coming years – even companies like BMW and Mercedes-Benz are getting in on the game.

But it’s the Renault Zoe causing the biggest stir right now. With the government’s 5,000 plug-in car grant included, pricing starts at only 13,650.

For comparison, that’s not dissimilar to Renault’s own Clio, and enough to make the Zoe a realistic option for some. If virtually all of your driving is around town, wouldn’t it make more sense to buy the electric car, rather than a petrol or diesel?

There’s only one way to find out – by comparing each in detail. We’re taking three Renaults, a Zoe Expression, a Clio Expression+ TCe ECO, and a Clio Expression+ dCi ECO, and looking at the costs you might face over each year of ownership.

Renault Clio yellow


It might sound obvious, but the first thing you’ll be doing is buying the car. Most manufacturers offer finance these days, and some banks do even more competitive rates – so monthly hire-purchase costs will be similar for all. But what are you paying overall? Let’s look at the list price of each car.

Renault Zoe Expression: 13,650 on-the-road (after 5,000 government grant)

Renault Clio Expression+ TCe ECO: 13,245 on-the-road

Renault Clio Expression+ dCi ECO: 14,345

It’s a good start for the Zoe. After the government grant, it’s only a few hundred quid more expensive than the turbocharged petrol Clio, and 695 cheaper than the diesel. If price was the only thing putting you off electric cars before, then that barrier has effectively been removed.

Renault Zoe side

Tax and congestion charging

All vehicles ace this section. The Zoe, as an electric vehicle and therefore zero local emissions, is a zero-rated Vehicle Excise Duty car, and exempt from London’s congestion charging scheme.

And with CO2 of 99 g/km and 83 g/km for the petrol and diesel Clios respectively, both also offer free road tax and zero congestion charging.

Points all round then? For the time being, at least. If you live in London, you’ll have heard of Mayor Boris Johnson’s plans to lower the CO2 threshold for free C-charge to 75 g/km. If that goes ahead, then neither Clio will be exempt and owners will pay 10 per day to enter the zone. The Zoe however will remain free for the forseeable future.

Renault Clio side


More good news for all three cars. At the moment, both Clios and the Zoe all come with Renault’s 4+ package.

4+ includes four years and up to 100,000 miles warranty, free servicing for four years and up to 48,000 miles, four years roadside assistance, and if required, four-year finance packages. It’s free for all three cars, so that takes another cost away.

Renault Zoe interior


All three cars are relatively inexpensive to insure – great safety ratings, relatively low-powered engines, good protection against theft and relatively inexpensive parts costs all look good on the insurer’s balance sheet.

There are small differences, though. Using this author’s details, which include ten years experience, nine years no claims, 28 years old, living at a safe postcode, with the car parked at an office during the day and driveway at night, we got three equivalent figures from a popular comparison website.

The petrol Clio proved cheapest, with a premium of 180 for the year. Next up was the Zoe, at 194 for the year, and finally the diesel at 204.

There’s only 24 between cheapest and most expensive, which is unlikely to put anyone off any particular car.

Renault Clio interior

Fuel costs

This is the big one. How much will each car actually cost you to run on a daily, or monthly basis?

Let’s lay some ground rules. Firstly, mileage of 7,500 miles per year. Why 7,500? Partly because we’re assuming the driver is sticking mostly to city driving, so won’t cover the UK average of between 10,000-12,000 miles per year.

And partly because that’s what the basic Zoe’s battery leasing cost of 70 per month is based on. That price rather dictates the Zoe’s running costs, as we’ll find out below.

Electricity pricing is another constant: We’re assuming that the average electric car owner will do their best to get cheap electricity rates, so we’ve picked an Economy 7 tariff at 9.08 pence per kilowatt-hour (source: Energy Saving Trust).

At the time of writing, petrol cost an average of 137.9 pence per litre (6.21 per gallon – which we’re converting to, to make the sums simpler) and diesel 146.4 ppl (6.59 per gallon).

Renault Zoe charging

The maths

Renault quotes three range estimates for the Zoe – 130 miles on the EU cycle, 90 miles as a likelihood, and 60 miles as a worst-case scenario.

We’ll save you the tedious calculations, but that works out at 115, 166 or 245 per year in electricity depending on how many miles you get on a charge.

That looks pretty good next to the petrol and diesel Clios. The petrol’s 53.3 mpg urban rating would mean costs of around 873 per year, the diesel’s 78.5 mpg urban rating 629 per year.

Ah, but we’ve not yet included that 70 monthly battery rental yet. Now it adds up to a surprisingly expensive 955, 1,006 or 1,085 depending on whether you manage 130, 90 or 60 miles of range. In other words, much more than the petrol or diesel Clios.

Well, possibly.

You see, 60 and 90 miles are Renault’s realistic estimates for Zoe range, compared to the official 130 miles. If we’re realistic with the petrol and diesel too and knock 15 percent off each urban figure – 45.3 mpg for the petrol, 66.7 for the diesel – then their respective annual fuel costs rise to 1,028 and 740.

The diesel is still a fair bit cheaper then (if you still think you can do 66 mpg around town…) and the petrol surprisingly close to the electric car.

Renault Clio driving


With so many variables, it’s hard to come up with definitive numbers. Drivers with magical footwork skills might be able to get close to the Zoe’s 130-mile range around town, hugely improving the overall running costs. And potentially, both petrol and diesel cars will do worse than even our 15 percent-reduced urban figures.

Then there’s the matter of the Zoe’s other rental schemes, all of which are more expensive per month.

Mileage varies too – both Clios would get better mpg on the open road than around town, and the higher the annual mileage, the less realistic a Zoe would be as everyday transport.

Back in the Zoe’s favour, what might the price of fuel do over the next few years? It’s unlikely to go down, and while electricity prices are rising too, the tiny volume electric cars use means the price gap between filling an electric car and filling an internal combustion vehicle will forever widen.

And depreciation? We’ve been unable to gather figures for any of the cars. Depreciation on the Zoe is a complete unknown – it may hold value well thanks to the battery rental alleviating the fears of used buyers, or it might drop like a stone if sales are poor.

Renault Zoe rear


All three cars cost similar money to buy. All three are currently free to tax and free to drive into London. All three get a four-year servicing, warranty and roadside assistance package from Renault. And all are similarly affordable to insure.

However, the diesel has cheapest fuel costs here, saving 266 over the Zoe – if you can match that 66 mpg estimate. With only marginally more expensive insurance and all other things being equal, it wins on costs.

Whether it wins as the best city car is open to interpretation. The Zoe is completely silent, easier to drive thanks to its auto gearbox (well, lack of a gearbox entirely), and lacks many of the expensive service components of regular vehicles.

You’ll never have to visit a fuel station again, nor handle a gloopy diesel pump. You won’t be caught out if Boris drops the C-charge threshold to 75 g/km, or even 50 or 25 g/km.

Some drivers will forever be put off by the lack of outright range, so the Zoe isn’t perfect. But it’s made electric cars a realistic option.

We just wish Renault would knock another ten or twenty quid from the cost of the battery lease – it’d make the Zoe a no-brainer for city drivers.

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