Currently, 14 countries around the globe have proposed banning the sale of passenger vehicles powered by fossil fuels (petrol, gas and diesel) over the next few years.

Leading the pack is Norway, which has committed to clear their streets of all vehicles with internal combustion engines by 2025, replacing them with zero-emission vehicles. That’s less than 5 years away.

Following close behind are Sweden, Slovenia, the Netherlands and Ireland, promising to ban the sale and registration of new petrol and diesel cars by 2030.

In a spread-out, car centric country like Australia, no similar promises have been made, but a recent report by the Electric Vehicle Council showed an overwhelming increase in interest in electric vehicles.

According to the report, more than 6700 electric vehicles were sold in Australia last year. This number may not seem huge, but it’s up a whopping 203% from 2018, when just 2216 rolled out of showrooms.

While the future is looking overwhelmingly electric, a number of alternative fuels have been proposed, trialled and implemented over the years. Here’s a quick breakdown of some of the most influential.

Electricity

Electric vehicles fall into 3 categories – hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs) and battery electric vehicles (BEVs) – depending on the way they utilise electricity.

Hybrid electric vehicles

HEVs, or hybrids as most of us know them, have been available to the public since 1997, when Toyota released the first-generation Prius. Not to be confused with EVs, hybrids are powered by a conventional engine as well as an electric motor. The ‘regular’ engine does the majority of the work, while the electric motor assists, with the main goal of improving fuel economy. Hybrids can’t be plugged in and charged from the grid, so they still rely heavily on their petrol-powered engines.

Plug-in hybrid electric vehicles

PHEVs work in a similar way to hybrids, except their batteries are bigger and can be plugged in to charge. Also, their electric engines are more powerful than those in hybrids and can propel the car without the use of a conventional engine.

A somewhat mysterious vehicle called the BYD F3DM was the first mass-produced plug-in hybrid, launched exclusively in China in December 2008.

Battery electric vehicles

BEVs are also known as pure electric vehicles. Unlike the other EV types, they’re powered only by batteries. Though only available to purchase by a select few, the General Motors EV1 was the first mass-produced, electric vehicle, available from 1996–1999.

Hydrogen

Hydrogen cars are EVs, but their batteries don’t need to be recharged at a power outlet. The vehicle’s tank – made of carbon-fibre – is filled with hydrogen gas at a service station bowser, much the same as a petrol-powered vehicle.

The gas then mixes with oxygen from the air, in a fuel cell, to create electricity. This both drives the car and can charge the battery. As long as there’s hydrogen in the tank, the vehicle’s electric motor will continue to run.

They have a similar range to a regular car, and the only exhaust that leaves the tailpipe is water vapour.

While all of this sounds fantastic, the main roadblock for hydrogen vehicles is how energy and water-intensive they are. The cost to create the technology and develop supporting infrastructure is huge, plus, fossil fuels are currently needed to produce hydrogen fuel cells.

Hydrogen vehicles aren’t available in Australia, as a network of refuelling outlets will need to be established across the country. But this isn’t just a passing trend – there are already thousands of hydrogen cars on roads overseas, and plenty of filling stations to keep them going. In fact, before COVID-19 hit, the ACT government was planning to test a fleet of 20 hydrogen vehicles on public roads.

Toyota launched the world’s first mass-produced hydrogen fuel cell vehicle – the Mirai – in December 2014.

Ethanol

E10, available at select petrol stations, is a blend of ethanol and unleaded petrol, made from renewable sources such as sugar, starch and cellulose.

It’s usually slightly cheaper than 91 octane fuel and cars will emit around 7% less greenhouse gasses when using it. However, they’re not as fuel efficient.

Most cars built after the year 2000 can run on E10 fuel, but it’s important to do your research before opening your fuel cap. Filling up a car with E10 that isn’t compatible could result in damage to the fuel system and catalytic converters.

Compressed air

Peugeot, Citroen and Tata have all tried their hand at developing a compressed air-powered car with varying levels of success.

These engines are driven by extremely high pressurised air (up to 4500psi), stored in a tank. Instead of using an ignited fuel-air mixture to drive their pistons, these run on nothing but the expansion of compressed air.

While, on paper, air-fuelled engines have plenty of positives – some of the most obvious being that they don’t use fossil fuels and cost less to produce – there are a number of downfalls.

The main issue is that the air has to be extremely highly pressurised and there has to be a huge amount of it stored in the car. By the time the pressurised air has been transmitted to a compressor, fed into the car’s air tank, then converted to mechanical energy, the majority of its power is lost.

But wait, there’s more

Of course, these are just a few of the many alternate fuels that have been trialled and tested over the years. Others include kinetic energy, steam, nitrogen, heat, compressed natural gas and – of course – the sun. Unfortunately all have experienced their fair share of roadblocks.