from Illuminate, Autumn 2021
Hydrogen fuel is a practical and sustainable fuel that has the power to revolutionise energy transition. Recently, it has been successfully trialled, with 24 buses in London working on hydrogen as an alternative to petrol. However, hydrogen has some drawbacks, such as lack of infrastructure and its high cost.
Hydrogen is the most common element in the universe, but it makes up only 0.14 percent of the Earth’s weight. The vast majority of this ubiquitous element is locked in compounds such as water, which makes up at least 70 percent of Earth. Liquid hydrogen, the main hydrogen fuel, is also relatively easy to produce, as a byproduct of electrolysis or running an electric current through water. This splits the molecules into separated hydrogen gas and oxygen gas, both of which can be easily extracted; the gas is then cooled to become liquid.
Hydrogen fuel cells work similarly to a battery: H2 is passed through an anode, which splits it from its electrons. This turns it into H+, which passes through an electrolytic membrane. The separated electrons are passed through a wire, creating a current. On the other side, air is let through to allow oxygen particles in the air to interact with the ionised hydrogen particles. The ensuing reaction forms water, which can be released through an exhaust pipe along with the other gases in the air.
Benefits include that it is a completely green fuel due to an absence of burning. Hydrogen fuel cells do not produce harmful CO2, CO or even worse chlorofluorocarbons; the only byproduct of a fuel cell is water. This means that no emissions are released and thus air quality is improved. Furthermore, hydrogen is efficient since its fuel economy is twice as efficient than that of oil or gas and it has the highest energy content of any fuel by weight. Unlike an electric car, hydrogen has a very short charging time, but has the same range as that of a fossil fuelled car. Hydrogen does not require large areas of land to generate, unlike hydroelectricity and wind power, which can potentially ruin ecosystems and damage the natural environment. From a political perspective, hydrogen fuel would decrease reliance on fossil fuels and countries with oil-economies, which could help the economic stability of places with fewer natural resources.
Unfortunately, hydrogen is not perfect. Although theoretically better for the planet than crude oil and gas, hydrogen needs large amounts of electricity to produce, since the only way to separate it from oxygen is electrolysis. Besides, electrolysis itself and fuel cells sometimes require precious metals such as platinum, which means that the cost of these appliances can be high. For hydrogen to be fully green, the electricity needed to produce it would have to be from a renewable source, which takes longer to produce than fossil fuelled electricity. It also needs a lot of energy to store as a liquid, since it has the incredibly low melting point of - 259 C; this energy would again have to be renewable. Finally, hydrogen is expensive and there are very few vehicles and appliances adapted to use it as a fuel. Most refuelling stops are gas and petrol, and although hydrogen is twice as efficient as either of these, it is still very difficult to source. Additionally, no infrastructure is currently in place, with hydrogen needing possibly hundreds of miles of high-pressure pipelines, hydrogen refuelling stations along roads and highways and the capacity to store hydrogen underground. Refuelling stations not connected to pipelines need to have hydrogen transported by trucks or trailers, and besides, there is a lack of power plants that can actually produce the hydrogen.
Is hydrogen fuel a sustainable alternative to fossil fuels in the future? Ultimately, it has the potential to be. Hydrogen is abundant, sustainable, and efficient to use, however, it is difficult to produce and needs new infrastructure to be mass-produced effectively.
Written by Grace