Why is the world still using so much petrol? There are more than a dozen alternative fuels currently under development or in production to power the vehicles of the future, and some are available today.

The United States government produced a data centre for the six most common alternatives available, outlining their advantages and the challenges that still exist to bring them to a larger market.

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Biodiesel

Biodiesel is a renewable fuel which can be made from vegetable oils, animal fats, or recycled restaurant grease. Believe it or not, this can then be used in diesel vehicles already on the road because its physical makeup is similar enough to petroleum diesel, but it burns much more cleanly. Biodiesel is also much safer. Not only is it easier on the environment if spilled, but it has a flashpoint of over 130 degrees celsius, compared to 52 for normal diesel. Pure biodiesel, known as B100,  reduces carbon dioxide emissions by more than 75% compared with normal diesel.

Electricity

Electric cars have been around a while but so far have struggled to enter the mass market. Many hybrid vehicles now use electricity to reduce fuel consumption and thus reduce fuel costs. While the power grid might be readily available in the west, charging stations for these vehicles remains limited. In the United States, for example, there were only roughly 8,800 charging stations in 2014.

Ethanol

Ethanol is an alcoholic renewable that is made of the same kind of alcohol you find in alcoholic beverages. Ethanol is then mixed in various degrees with traditional petrol. The production and use of ethanol could reduce greenhouse gas emissions anywhere between 52 and 86 percent. Additionally, the infrastructure already exists to deal with ethanol, because it is the equipment used to store and dispense gasoline, just with modifications to some materials. The drawback, however, is that ethanol has less energy than petrol, meaning you need more of it to get the same results.

Hydrogen

Hydrogen has virtually no greenhouse gas emissions. Power is generated in a hydrogen fuel cell, which will only emit water vapor and warm air. The difficulty is that hydrogen fuel must be extracted from water, hydrocarbons or other organic matter. The process of doing this involves either natural gas or high levels of energy which, of course, come from power plants. Storing hydrogen is also a challenge, because it requires high pressures, low temperatures, or chemical processes to be stored compactly.

Natural Gas

Natural Gas is already widely used for a number of purposes around the world. It is an odorless mixture of hydrocarbons, most of which are methane. Natural gas is considered a fossil fuel, but an alternative known as renewable natural gas does exist. Biomethane is produced from waste, either from livestock or even landfills through a process called anaerobic digestion. In this series of processes, microorganisms break down biodegradable material. A major advantage to renewable natural gas is that it is chemically identical to its fossil fuel brother, meaning the existing infrastructure is perfectly useable.

Propane

Propane, or liquefied petroleum gas, is clean-burning and high-energy, making it a tempting alternative. Propane vehicles are typically more expensive than those running on petrol, though inversely propane is often cheaper than petrol. Nevertheless, propane’s reduction of greenhouse gasses is only about 10%.

Author: Donald Armbrecht is a freelance writer and social media producer.

Image: A staff member plugs a charger cable into Toyota’s i-Road electric vehicle in Tokyo. REUTERS/Thomas Peter