Diesel, Petrol, Electric - Which One is Right for Me?

by Dave Humphreys | 6 min read     July 23rd, 2018

These days there is no shortage of choice in the car market, but choosing the right car isn’t just about the one you like, or how many seats it has. Buyers now face more significant decisions as to what will power their car, and each of these variants offer different pros and cons depending on your driving habits. So how do you best decide which type of engine and fuel type is right for you? We’re going to run through the various choices to help you decide which might be the most suitable based on typical experiences and traits of each type of power source.


There is an ongoing debate as to the future of diesel engines in passenger cars, and while its market share is decreasing, it remains the dominant fuel type. This popularity is mostly for economic reasons including running costs and taxation. That said, diesel cars typically do cost more to purchase, and they can also incur higher servicing and repair costs. Traditionally, diesel cars have also enjoyed stronger residual values, but with growing uncertainty as to the future popularity of diesel cars, this may be something that changes in time.

For some people, diesel still makes the most economic sense. The technology focuses around being as fuel efficient as possible over very long distances. If you’re the type of driver that typically does above average annual mileage, mostly on motorways, then diesel is still likely to be the best solution for you. It’s not uncommon for family-sized cars to be capable of covering well over 1,000 kilometres between fill-ups.

Larger capacity diesel engines, from 2.0-litres and upwards, tend to offer higher torque outputs or pulling power, in other words. This increased power lower down in the rev range makes them ideal for towing, with many larger SUVs capable of pulling up to 3.5 tonnes. It’s one of the same reasons why most commercial vehicles are diesel-powered. If you’re running a company car, you will most likely be limited to using a diesel engine for accounting and financial reasons.

However, if you’re a private user and tend to mostly do only urban commutes that don’t exceed a couple of hundred kilometres per week, a diesel car may not serve you best in the longer term. It is in these types of scenarios that diesel engines can run into problems down the line, as the complex exhausts systems can become clogged leading to a variety of issues. On longer motorway journeys those exhausts systems get the opportunity to heat up sufficiently and burn off those particles, hence why these cars are more suited to drivers covering greater distances.


Man fueling car

Modern petrol engines have made a lot of improvements in both reducing emissions and fuel consumption in recent years. Another trend with petrol engines has been downsizing. Smaller capacity engines are more frequently now turbocharged to provide the necessary boost in performance. In some cases, this can see larger cars using engines with a capacity as small as 1.0-litre without seeming underpowered.

For the most part, opting for a petrol engine these days is most suited to people who are typically doing low to average weekly distances and generally in urban areas. The increased use of start-stop technology, which momentarily shuts off the engine at a standstill helps conserve fuel in traffic. More engines are also now employing cylinder deactivation, which can turn off one or two of the engine’s cylinders to further lower fuel consumption when the car is cruising along. All of these things combine to make petrol cars travel further between refills.

You might associate petrol engines of old with having higher annual motor tax rates, but nowadays many of the newest and cleanest petrol engines fall into almost the same taxation bands that made diesel so prevalent after 2008 when the bandings changed in Ireland. Another improvement comes with automatic transmissions. Nowadays, these can be more efficient than the regular manual gearbox, contributing to lower fuel consumption and emissions. Unless you frequently undertake long-distance driving, you may want to take a second look at what petrol offerings are now available.


We’ve had hybrid cars for more than two decades, but only now they are becoming more widespread thanks to reductions in production costs. Simply put, a hybrid comes with a small battery that is capable of propelling the car for very short distances at low speed. For the most part, it is the petrol or diesel combustion engine that does most of the driving, and these types of cars are almost always automatic.

Having the battery and electric motor supplement the performance of the regular engine can help to reduce fuel consumption, especially when being driven in urban settings where speeds are lower and with frequent stop-starts.

Unlike both plug-in hybrids and electric vehicles, hybrid cars do not require you to do anything other than refuelling them in the same way you would with a diesel or petrol car. The car’s onboard systems manage how the drivetrain works in every scenario.

Plug-in Hybrid

If you like the idea of owning an electric vehicle, but you’re worried about running out of battery power, a plug-in hybrid serves as an ideal middle ground. It works in much the same way as a regular hybrid car but gains a larger capacity battery that usually lies in the rear, below the boot. With a larger battery, the vehicle can travel solely on electric power for extended distances, in some cases up to 50 kilometres, before the combustion engine restarts. In general, PHEVs (plug-in hybrid electric vehicles) drive in the same way as hybrids, with both motors activating according to the driving scenario.

You do still need to plug it in to charge that battery, just like an electric vehicle. This recharging can be done via a home wallbox charger or public charge point. With some models, it is possible to use the car’s combustion engine to recharge the battery although this is a less efficient method. Most PHEVs also offer drivers the ability to hold or maintain the car’s current state of charge. This option is there so that you can reserve your electric driving for another point in the journey, such as entering a city’s low emission zone.

If you happen only to take very short journeys, and can plug the car in when you get to work, for example, the likelihood is that you will spend a good proportion of your time driving with only the battery powering the car. The benefit of a PHEV is that you don’t need to suffer range anxiety, as once the battery is depleted the combustion engine immediately starts without you having to do anything as you continue your journey.


Woman holding charger for car

The choice of battery electric vehicles (BEVs) is growing each year as an increasing number of mainstream car brands begin to introduce more models. There is a widespread consensus that the long-term future of mobility lies in electric power, though the exact timeline for this remains the topic of much discussion. At present, driving ranges with BEVs are just starting to creep into the 300-kilometre zone, with others offering more but at a higher cost.

Unlike most other types of propulsion, with an electric vehicle, you need to consider your situation carefully including what purpose you intend to use the car. At present, most buyers need to meet the car’s criteria rather than the other way around. Working out what your typical usage and driving distance covered daily and weekly is vital. It’s also important to factor in that electric driving ranges reduce in winter months as the colder temperatures can lower the efficiency of the battery and you’re likely to use heating more which also has an impact on driving range.

It is highly advisable that BEV owners have a method of charging the vehicle at home, ideally in a garage or with a driveway in which you can install an external wallbox charger. You will need to factor in the costs of having this work carried out into your budget. Presently there are grants available towards the installation costs, but you should investigate this before committing to the installation. Those living in rented accommodation, apartment developments or with only on-street parking will likely find a charging solution more difficult to achieve. There is still a public charging network, but it isn’t advisable to solely rely on this as your only means of recharging the car.

There are many advantages to driving a BEV, namely the significant reduction in running costs after the initial purchase. A full charge of 300 kilometres can cost as little as a few euros, in comparison to much more for the petrol or diesel equivalent. Maintenance costs can also fall as electric vehicles have fewer moving parts that require servicing.

One of the first things people notice about electric vehicles is just how quiet they are when on the move. This quieter operation does help to reduce stress during the daily commute. Electric drivetrains are automatic with many offering ‘one pedal driving’, whereby it is possible to drive using just the throttle pedal and lifting off initiates enough energy regeneration to sufficiently slow the car.


Information correct as of date of publishing. This blog will not be updated or edited so the information may become outdated.

Dave Humphreys
Motoring journalist on 2 & 4 wheels. Road Test Editor @CompleteCar, Editor @50to70 & @EngineRoomShow. Writer for @CE_editorial & more. AUTOBEST Jury member