While diesel and gasoline are the current heavyweights for fueling the automotive industry, this won’t be the case forever. The world is looking toward its energy needs, emphasizing alternative fuel sources with a minimal carbon footprint and an optimal fuel economy.

It’s no wonder that electric vehicles (EVs) and hydrogen-powered cars have sky-rocketed in popularity over the last few years. However, these are not the only options we have. Other fuel options include ethanol, natural gas, propane, and biodiesel, to keep our cars on the roads. Scientists have gone a step further in bringing a sustainable future within our sights by finding a way to convert waste coffee into biodiesel.

A history of alternative automotive fuels

We’ve been using conventional fuel sources — diesel, gasoline, and aviation fuel — for a long time. It wasn’t until the late 1970s that the term ‘alternative fuels‘ found its way into energy-related literature. This post-modern fuel excludes all petroleum products that are liquid under normal ambient conditions.

According to Encyclopedia, alternative fuels comprise highly volatile fractions of petroleum, like compressed natural gas, liquefied natural gas, and propane; chemically-obtainable fuels like hydrogen and methanol; and biofuels from plant material. Electric vehicles hold the mantle of alternative-fuel vehicles as only around 3% of their electricity comes from the combustion of petroleum.

Napa Know How acknowledges three alternative fuel vehicles. These future-oriented automobiles include:

1. Battery-electric vehicles — These cars use electricity as the main power source. They use rechargeable batteries to contain the power that is transduced into rotational motion thanks to the vehicle’s electric motor.
2. Fuel cell electric vehicles — These vehicles are hydrogen-powered. The combustible gas is stored in a tank. Hydrogen from the tank is converted into electricity thanks to the car’s fuel cell.
3. Hybrid vehicles — As you may have guessed from the name, these cars use both electricity and gas for power. The result is a motor vehicle with reduced tail-pipe emissions but improved fuel efficiency.

Can cars run on coffee?

Most of us are familiar with the fable, Rumpelstiltskin, where a poor miller’s daughter spins gold from straw. Looking for the next viable alternative fuel, British scientists decided to convert leftover coffee grounds into car fuel. Their ambition had the whole world watching the British TV series Bang Goes the Theory to test their project out.

We got to see a 1988 Volkswagen Scirocco transform into the heavily-modified one-of-a-kind automobile aptly dubbed the Car-puccino. The Coffee Car Mark 1 ran on gasification — a powertrain that converted carbon-laden coffee grounds into energy.

It has what appears to be a moonshine still on the back of the car, containing a charcoal stove filled with coffee ground pellets. These dregs of caffeine are broken down, releasing hydrogen and carbon monoxide. The hydrogen goes through a cooling and filtration process that removes tar. The gas then powers the engine’s pistons, causing motion.

This coffee-guzzler was driven from London to Manchester, spanning 210 miles. As reported by PC World, the Car-puccino clocked a top speed of 60 miles per hour during its pleasant-smelling maiden journey. It was a trip punctuated with several rest stops. As the entire journey required 150 pounds of coffee grounds, the car ran for about 30–45 miles before it needed a refill. The 1988 Volkswagen Scirocco’s original gas mileage stood at 22 miles per gallon.

A few years later, these scientists wanted to prove that a coffee-powered vehicle can zoom as fast as a gas-powered car. Thus, the Coffee Car Mark 2 came to be. It was tested out at an airfield bordering Manchester. This modified Ford pickup was able to record a top speed of 65 mph.

Viability of coffee as a fuel source

To be a viable and economical alternative to gasoline or diesel, the coffee-powered car had to have more pros than cons, therefore, proving its worth. It showed its potential by achieving maximum speeds of 65 mph. Not only did it accomplish this, but it was also able to go for long distances provided it was periodically refilled. Additionally, it crossed this milestone by using waste. It used a kind of combustion akin to wood-burning and could reuse coffee dregs previously thought of as garbage.  

However, the scales aren’t in favor of the Car-puccino, as ultimately, the negatives outweigh the positive aspects. Firstly, in an automotive world that favors a quick and powerful start on the car’s ignition, the coffee-fueled car struggles to keep up. It needs some time to burn fuel, so a slow start-up is expected with this vehicle.

Secondly, it’s space-intensive. Visually reports that you’ll need a huge boiler to facilitate the gasification process. Lastly, this biodiesel is pricier than gas. In the U.K., where this concept was tested, coffee per pound goes for between $9 and $20. This means to make the 210-mile journey from London to Manchester, you’ll have to spend 50 times more than the gas you’d require for a conventional internal combustion engine-powered car.