How our cars are powered isn’t as straightforward as it used to be. These days, there are a variety of ways in which a car could be ‘pushed’ forward, giving many options to drivers.

But how do these powertrains work and what are the positives and negatives of each? Here, we’re going to take a closer look at some of the main types of fuel and what they could mean for you.

Petrol

Petrol power remains one of the key ways to power our cars. Even with the increasing number of alternatives, petrol is still one of the most popular forms of propulsion, bringing reliable performance and the ease of filling up in a matter of minutes. There is also a great variety of petrol-powered engines out there, from compact, small-capacity units focused on efficiency to large, performance-orientated setups that you’ll find in the very latest supercars.

Essentially, a petrol engine mixes the fuel with air, ignites this mixture and uses the compression that you get from the ‘bang’ to drive the pistons up and down, moving connecting rods which are then turned into a rotating motion via the crankshaft. Hey presto, you’ve got propulsion and though this system has become more complex in recent times - and become controlled by electronic systems - it’s still the same basic setup that has been powering cars for decades.

Petrol is still one of the most popular engine fuels with it being widespread and easy to get hold of. A negative of it is that its price is often dictated by global oil costs - and if they go up, so does the price of petrol.

Diesel

Diesel may have fallen out of favour with buyers lately, but for many drivers, it remains a key fuel type. Particularly for motorists who do long distances at higher speeds - such as when you’re on the motorway - diesel can deliver far better efficiency and a more refined overall experience than petrol in these situations.

Diesel works in a similar way to petrol, but there are a few key differences. One of the key ones is the lack of a ‘spark’. Instead, an engine’s piston compresses the air in the system until its gets hot and at this point, diesel is sent into the chamber. At this point, it ignites and causes an explosion which, like petrol, drives the piston and provides to power for a rotational force to move the wheels.

The fuel from the black pump was hammered by the famous Volkswagen ‘dieselgate’ scandal and since then it has struggled to recover. However, modern diesel engines are some of the most efficient ever made, producing very little in the way of CO2 and returning excellent consumption figures, particularly over long distances. Diesel continues to be the choice of heavy goods vehicles - or HGVs - too.

Hybrid

Hybrids have grown in popularity lately as they bring an added level of electrification without the need to make the jump to fully electric vehicles. Today, there is a variety of hybrid engine setups, with ‘mild’ ‘regular’ and plug-in hybrids all bringing something different. Mild hybrids, for instance, bring a very basic level of electrification and work to take some strain off the engine but cannot be driven on electric power along, whereas plug-in hybrids bring far larger electric batteries which allows them to drive on solely battery power for a decent stretch.

Hybrid engines combine a petrol or diesel engine with an electric motor and battery. In self-charging or regular hybrids, the engine provides some power to the battery and motor so that the petrol motor acts more like a generator. Plus, most self-charging hybrids can harvest energy that would otherwise be lost when slowing down through something called ‘regenerative braking’ which essentially feeds energy back into the batteries when you hit the brakes. Self-charging hybrids can only run on electric power for short periods of time and at slow speeds, but they’re easy to use because they don’t need plugging in. However, they don’t offer the same level of electric range as a plug-in hybrid.

A plug-in hybrid, meanwhile, has a far larger battery and electric motor setup. Because of this, they can be charged up - like an electric car - and you’ll be able to drive one for longer distances on electric power alone. However, like a regular hybrid then too can be charged by the petrol or diesel engine - though it’s more efficient to plug them in. Plug-in hybrids are often more expensive to purchase than regular hybrids, but they do offer far lower running costs and can be significantly cheaper to tax because of low emissions, too.

Electric

Electric vehicles are a hot topic at the moment. There’s a big push towards electrification in the wider industry as manufacturers look to lower their global environmental impact, while legislation in the vast majority of countries means that electric power is what a lot of drivers are heading towards.

Electric vehicles store energy in their batteries, which are often mounted underneath the main floor of the car or occasionally under the boot. Through complex wiring, this electrical power stored in the batteries is transferred to a motor - or motors, on some cars - which then drives the wheels. You can charge the batteries up in a variety of ways, including a home wall box or a faster public charger and there are varying speeds at which you can top-up an EV. Some of the most powerful public chargers are now capable of taking an EV from 10 to 80 per cent in under 20 minutes, in fact.

The positives for EVs are their lack of tailpipe emissions and while there are, of course, aspects of the manufacturing process which create CO2, electric vehicles can have an immediate impact on lowering localised emissions. Plus, they provide a lot of performance and can often out-pace an equivalent petrol or diesel car. Naturally, their drawbacks lie in the charging process; those with home chargers can find owning an EV a breeze, but those who rely on the public network can often find themselves paying a lot for energy and having a less streamlined experience. In addition, EVs often cost more than their equivalent petrol and diesel cars.

Hydrogen

Hydrogen is, technically, another form of electric vehicle but it’s one which is seen by many as a true alternative to ‘traditional’ combustion-engined cars. Sometimes known as fuel-cell vehicles, hydrogen cars have a closer ‘refill’ time to petrol and diesel cars and can bring very long ranges between the need to top-up the tank.

It’s that tank which is topped up with compressed hydrogen. This is then mixed with dioxygen from the environment around the vehicle and fired at the ‘fuel cell’ onboard the vehicle. Doing so kickstarts an electrochemical reaction which helps to produce electricity, heat and water vapour - with the second two being the only by-products of the process. The electricity created is then channelled to the electric motors and these then power the car forward.

Hydrogen is a clean-running alternative and, because of the gases’ abundance, could prove to be a genuine front-runner in the market. However, there is currently just a handful of hydrogen filling stations in the UK, while only two production hydrogen vehicles remain on sale and neither are all that popular.