According to the International Energy Agency (IEA), as of 2018, there were 5 million electric cars already on public roads.
According to the International Energy Agency (IEA), as of 2018, there were 5 million electric cars already on public roads.
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Alternative Fuel Alternative fuels for cars: what does the future hold?

Author / Editor: Jamie Thomson / Erika Granath

Ever since the first gasoline internal combustion engine was created in 1884, petrol (and from the 1930s onwards, diesel) has dominated the automotive industry. However, as these fossil fuels continue to deplete, the days of petrol and diesel cars are numbered.

Governments the world over, are looking to cleaner, sustainable alternative fuels and many countries including Norway, France and the UK, have pledged to ban the sale of new petrol and diesel cars by 2040.

Some cities, including Paris, Rome and Los Angeles have also signed the Fossil Fuel Free Streets Declaration, promising to ban vehicles that emit harmful gases by 2030.

With this global collective effort to phase out petrol and diesel cars, many alternative fuels are being explored. Some are more viable than others, but they all have two things in common—they’re clean and they’re sustainable.

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Let’s take a closer look at these alternative fuels in more detail:

Liquefied Petroleum Gas (LPG)

LPG, or Autogas, as it’s also known, is a type of 'liquid gas' that currently fuels around 21 million cars globally. Whereas LPG was traditionally burnt off and wasted, it’s now recognised as a low-carbon fuel.

Some car manufacturers in the UK, such as Volvo and Vauxhall, also offer LPG as a bi-fuel that can be swapped with petrol when LPG runs out.

Globally, 21 million LPG-fuelled cars may sound like a lot, but it only accounts for around three percent of vehicle fuel. Although it’s more affordable than petrol and diesel, LPG systems require regular maintenance and MOTs are expensive.

LPG tanks also take up a lot of space within a vehicle, so it’s more common to find them in larger SUVs.


Electricity is regarded as one of the most viable alternative fuels and it’s already being used to power cars through lithium-ion batteries. The great thing about electricity as a fuel, is that it can be generated from a wide range of renewable sources, including solar and wind power.

According to the International Energy Agency (IEA), as of 2018, there were 5 million electric cars already on public roads. They do, however, vary in price, with Tesla’s Model S, being one of the more expensive vehicles on the market.

It’s still early days for electric vehicles and battery life is still limited to a range of around 100 miles in exchange for several hours of charging.


Biofuels like ethanol, are made from plants. They’re carbon neutral as the CO2 that’s absorbed is equal to that which is released when burned. Biofuels are also considered renewable, as plants regrow after they’ve been harvested.

Although there aren’t many 100 percent compatible biofuel cars on the road, most modern petrol and diesel car models can run on E10 fuel, which contains 90 percent regular unleaded and 10 percent ethanol.

The Association des Constructeurs Européens d'Automobiles (ACEA) has published a list of E10 compliant vehicles.

The biggest drawback to biofuel cars is their current cost. Although waste oil can be secured affordably, there’s no infrastructure to support it sustainably.


Hydrogen is often considered as a long-term fuel source for cars as it produces zero emissions and its only by-product is water. Compared to electric vehicles, hydrogen cars are quick to fill up and they give a good fuel range.

Hydrogen is used to power electrochemical fuel cells in a car by combining hydrogen from the tank with oxygen to produce electricity to run the motor.

There are some hydrogen cars already on the market, such as the Toyota Mirai but they’re few and far between. According to online publication, InsideEVs, there are only 6,500 hydrogen fuel cell cars in the world.

Some of the challenges that hydrogen cars face include a lack of infrastructure to support refuelling and the cost of manufacturing fuel cell technology.

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Nitrogen is the most abundant gas in our atmosphere. It accounts for around 78 percent of the air that we breathe. When liquid nitrogen is stored in a pressurised container and released, it’s transformed from liquid to gas and can be used to drive a rotary engine or piston. Nitrogen also produces few harmful emissions.

One example of a car that runs on hydrogen is the Hyundai Nexo. The car is powered by a second-generation hydrogen fuel cell system that only takes 5 minutes to fill and offers a range of 414 miles.

As a fluid, however, nitrogen is very dangerous and there’s currently no refuelling infrastructure in place to sustain it as an alternative fuel. As a result, it’s currently less efficient that fossil fuels and it still requires electricity to produce it.


Kinetic energy, or regenerative braking, as it’s also referred to in the automotive industry, is when brake energy is used to charge up a battery. When a car slows down, the energy is converted to electric charge, rather than it being lost through heat and noise. Many electric cars already have regenerative braking systems built-in, like the Toyota Prius Hybrid.

The use of kinetic energy as an alternative fuel is expected to increase in the future to make better use of the moving energy that a car possesses. This in turn, reduces the amount of fuel that’s required to run the car.

However, kinetic energy transfer isn’t 100 percent reliable, so an additional fuel is also required to store enough electricity in the battery.

Compressed Air

It may not be the first alternative fuel that comes to mind, but compressed air can be used to drive the pistons in a combustion engine in place of petrol.

Indian car manufacturer Tata have developed a concept car that runs on a tank of compressed air, which can be pumped in through a charging station, or via an electric engine.

The issue with compressed air is that the energy required to compress the air in the first place makes it unsustainable. A far more likely use of this fuel in the future would be as part of a hybrid petrol car, where air can be released as required, so the car can run on air power temporarily.


Steam cars aren’t a new concept and have been around since the 17th century. In fact, steam cars were replaced with the modern internal combustion engines that we know today. However, as we know, history has a habit of repeating itself and steam could become a viable alternative fuel in the near future.

When used as part of a closed loop system, any energy source can be used to heat water to turn it to steam. Steam engines themselves don’t produce any emissions, other than water and they deliver instant energy.

According to a company in Florida called Cyclone Power Technologies, their steam-powered Cyclone Engine is close to being tested in a commercial vehicle. Watch this space …