Transportation currently accounts for 21% of global carbon dioxide emissions. Most vehicles and planes are powered by internal combustion engines, which burn fuel and oxygen together to create energy. Burning gasoline and diesel fuels produces a large amount of carbon dioxide, which contributes to global warming. However, there are various alternatives that can make transportation more sustainable, including using electric batteries, hydrogen fuel cells and electrofuels.
Electric vehicles are powered by batteries which can be plugged into an outlet to recharge. These vehicles do not emit carbon dioxide or pollutants into the atmosphere, making them more sustainable. Since electric vehicles have become popular recently, many car manufacturers now make electric or hybrid vehicles.
Other alternatives currently in development to make transportation more sustainable are based on hydrogen. The process of liquefying hydrogen was originally discovered at the Ri. In 1892, James Dewar invented the vacuum flask at the Ri as part of his research into cryogenics- the study of materials at very low temperatures. The flask minimizes heat transfer and maintains low temperatures and was used by Dewar in 1898 to create liquefied hydrogen by pre-cooling hydrogen gas and expanding it in the flask at temperatures low enough to be stable in liquid form.
Today, there are many ways to extract hydrogen so that it can be used in transportation. Hydrogen fuel cell vehicles do not have internal combustion engines and instead use fuel cells which power an electric motor. These fuel cells combine hydrogen and oxygen to produce electricity, which drives the motor. The only waste product of this process is water, and no carbon dioxide is emitted. Despite this, there are many limitations to using hydrogen in transportation. Since hydrogen has less energy by volume, the tanks needed to store liquid hydrogen are larger and heavier. Furthermore, liquid hydrogen is more expensive than traditional fuels, and there is currently no network of hydrogen filling stations.
Additionally, electrofuels can be used to power internal combustion engines in vehicles and planes and are a more sustainable alternative to traditional fuels. Electrofuels are produced through combining captured carbon dioxide emissions with hydrogen. Although these electrofuels also emit carbon dioxide when used in engines, the carbon dioxide emitted is equal to the carbon dioxide initially captured, making it a net zero carbon process. Using electrofuels does not require much change in infrastructure, since these fuels can be used to power existing internal combustion engines.
Overall, there are several technologies in development to make transportation more sustainable, many of which link back to James Dewar’s experiments at the Ri.