Last updated on 29 January 2019
Hydrogen is cheap and its combustion produces only water (no CO2). It produces 3 times as much energy as an equivalent quantity of petrol. So, why don’t all we drive on hydrogen?
Simply because there is a flip side of the coin. Besides all these advantages, hydrogen has a series of disadvantages for running a car.
Hydrogen is the most abundant chemical component in the universe. Contrary to petrol, gas or coal, hydrogen cannot be found in its raw form in nature. It is not extracted by mining but manufactured by a chemical process.
To obtain hydrogen, two processes are possible:
At present, 4% of the hydrogen produced worldwide is made by electrolysis and 96% by chemical transformation of fossil fuels, mainly natural gas (48%).
If hydrogen were produced solely from renewable electricity, it would be the ideal fuel: unlike petrol, diesel and natural gas, its combustion with oxygen from the air produces only pure water, no CO2 and no particulates whatsoever. It is also non-toxic.
Hydrogen contains three times more energy per kilogram than petrol and can be used in different ways, which is not the case for all other fuels:
Hydrogen can be used to store excess electrical energy produced by renewable energy generation systems that depend on weather conditions:
Hydrogen is very useful in the chemical industry. Moreover, there is a European network of more than 900 km of hydrogen pipelines connecting the north of France, Belgium, the Netherlands, and the German industrial basin of the Ruhr.
Here are some more examples:
Oil companies and electricity producers also have projects related to hydrogen. And others are even thinking of reviving hydrogen-filled airships to replace aircraft in the transport of non-urgent goods.
On the automotive side, however, the offering remains very limited: Hyundai and Toyota are the only manufacturers to offer a model priced at around 65,000 to 80,000 euros. Mercedes, BMW and Honda also have hydrogen car projects in the pipeline.
The classic combustion engine which equips petrol cars is not suitable for using hydrogen. We have to use an electric motor powered by a fuel cell, which transforms hydrogen into electricity.
This process raises questions about efficiency as it involves 2 electrochemical processes. First, the up-front manufacturing of the hydrogen and second, the conversion into electricity. At best, the fuel cell has an efficiency of 40%, and therefore an energy loss of 60%.
Furthermore, the fuel cell is very expensive (although some car manufacturers announce considerable price cuts) and is delicate and complex to operate. It also requires the use of precious metals, such as platinum, to manufacture it.
However, fuel cells can be useful for heavier technologies such as the space industry.
One kilogramme of hydrogen releases as much energy as three litres of petrol. However, hydrogen is the smallest and lightest element in the universe, and its energy density (energy per unit of volume) is very low. That means we need to store a lot of it under high pressure (700 bar) to obtain the amount needed to operate a car.
Specifically, a tank filled with 60 l of hydrogen (i.e. 5kg) equals only 13 litres of petrol.
Price full fuel tank
|Hydrogen car||15 €/kg||5 kg||€ 75||0,8 kg/100 km||625 km|
|Petrol car||1,45 €/l||60 l||€ 87||5-6 l/100 km||1090 km|
This high-pressure tank presents an additional risk if the vehicle is in a crash, especially as hydrogen is very volatile and highly inflammable.
Another solution consists of liquefying the hydrogen to store it in large quantities in a suitable tank, but that consumes a lot of energy and raises efficiency questions once again.
To complete the picture, there are only a few hundred service stations in the world offering hydrogen (of which one is in Zaventem and another in Hal). Four more Belgian service stations are already planned. By 2020 the Benelux should count 8 hydrogen service stations in total. That means filling up is not easy!
With regard to mobility, hydrogen is one of the avenues being explored to replace petrol and combustion engines. While not everyone believes in the future of hydrogen for this particular use, everyone agrees that we will need multiple solutions to meet the energy challenge.
In the field of alternative vehicles, cars powered by natural gas are another very interesting concept and easier to implement technically. Just like the electric car. Take a look at our dossier to find out everything about electric and natural gas vehicles.
At the European level, the Hytrec project aims to develop the hydrogen pipeline network as an energy carrier across northern Europe, from Scotland to Denmark, Belgium and Germany.
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