When deciding which fuel – or power type – type is best for you, you shoulder consider several factors including:
• How much it will cost you in fuel or electricity
• Other running costs, including tax and depreciation
• The type of driving you do
• Environmental concerns
• How easily you can live with the car
Those advantages have to be offset against the fact that petrol cars have higher fuel consumption (worse mpg) than diesels, so you’ll have to fill your tank more often. As such, petrol cars are at their most cost-effective for those that cover less miles.
In terms of environmental impact, petrol cars generally have lower nitrogen oxide (NOx) and particulate emissions than diesels but they do emit more CO2.
They’ve developed something of a bad reputation for pollution, and do tend to produce more nitrogen oxide (NOx) and particulate emissions than petrol, but the latest diesels meet Euro 6 regulations, which set a strict limit on harmful exhaust emissions.
Modern diesel engines have a diesel particulate filter (DPF) to reduce emissions. These filters need regular long journeys at higher speeds to keep them working properly – if you generally only make short trips there is a risk that the DPF can clog up and fail.
Many diesel cars also need to be regularly topped up with AdBlue – a chemical that helps reduce the NOx emissions produced by the engines. If you cover a lot of miles you may have to top up with AdBlue yourself between services.
Overall, diesel cars still make sense for drivers who do a lot of miles, particularly on motorways. If you want to buy a diesel car, just make sure it meets the latest Euro 6 regulations.
Technology has developed rapidly over the past few years, easing concerns over battery range.
Running an electric car is often cheaper than petrol or diesel, because the cost to charge them is much lower than the cost of fuel for the same mileage. There are also major tax incentives, whether you are a private or business user.
Electric cars are generally more expensive to buy than a diesel or petrol equivalent, though, and the choice of brands and body styles available is limited. The number of options is increasing, however, with many car brands set to release new full-electric models over the coming months.
Your lifestyle and driving habits may well decide whether an electric car is right for you. While the number of public charging points has increased, finding one isn’t always easy, depending on where you are in the country. Home charging points are available, but not everyone is able to park directly outside their house or flat.
Electric cars are a great option for drivers who don’t often make long journeys and have easy access to charging points. As the technology and infrastructure for electric cars improves, they’ll become more and more viable.
Hybrid vehicles offer incredibly low emissions and combine a standard engine with at least one electric motor. They generate their electricity whilst you drive using two main techniques - regenerative braking, and an electrical generator.
Regenerative braking harvests heat and kinetic energy usually wasted during braking and converts it into electrical energy to be stored in the battery whereas an electrical generator runs directly off the combustion engine.
When cruising, particularly at low speeds, a hybrid will draw its power from the vehicle's fitted electric motor. When this speed starts to increase, the hybrid will seamlessly integratee the standard combustion engine in order to accommodate the greater demand. In particular testing cicrumstances such as driving over rough terrain or up a hill the behicle will use both systems alongside each other to gain extra power and torque.
One of the biggest benefits of a hybrid vehicle is that while its main fuel source is still gasoline it requires a lot less of this than a standard combustion engine vehicle and therefore running costs are often minimal.
Plug-in hybrids (PHEVs)
Generally, PHEVs drive on electric power first and swap to petrol (or, rarely, diesel), or a mix, once the full-electric range is used up. As such, they use significantly less fuel and have far lower emissions than HEVs.
While the official fuel economy and emissions figures mean there are currently big tax benefits for PHEVs compared with petrol or diesel cars it’s worth noting that real-world fuel economy will depend on how and where you drive and whether you keep the battery topped up. PHEVs are also more expensive than equivalent HEVs and petrol and diesel cars.
As a half-way house between internal combustion engines and full electric power, PHEVs are a fine option, but they do need to be regularly plugged in to get the best from them.
Mild hybrids (MHEVs)
It gives a small improvement in fuel economy and emissions over a conventional petrol or diesel engine, but not as much as an HEV or PHEV. Mild hybrid technology is becoming increasingly common in many petrol and diesel models, where it is included as standard.
MHEVs can’t run on electric power alone and most car brands don’t offer them as standalone models – it’s best to think of them simply as the next generation of petrol and diesel cars as we move towards increasing electrification.