Hydrogen is a part of all clean energy discussions at Instituto Superior Técnico in Lisbon. It also forms a sizable chunk of the coursework of my master’s with EIT InnoEnergy. Hydrogen is a subject particularly close to my heart. So, in this article, I have tried to simplify Hydrogen Energy and its role in the future of Clean Energy for everyone to understand.
Hydrogen classifications
Hydrogen is the most abundant element on earth. It produces no harmful emissions after combustion, just water vapor. So, using it for our energy needs is obviously a promising idea, isn’t it?
Ah, I only wish solving the climate crisis was this obvious. Let us dive into this seemingly easy but complex solution: hydrogen energy.
You see, Hydrogen is a “clingy” element. You will always find it bonded with other elements, like oxygen (H2O) or carbon (CH4). This is where the main challenge lies. To use it as a fuel, we need to separate it from other elements and form H2. And, to break those bonds, we need to supply energy. Basically, Hydrogen energy needs energy to be created.
So, this means, hydrogen is not an energy source, but an energy carrier. More like a prepaid sim card. To really determine how clean or emissions-free hydrogen is, we have to analyse the energy source that is used to produce the hydrogen.
Scientists have classified hydrogen in different colours based on the energy source used to produce it. The different colours of hydrogen and the associated primary fuel for generation. It is important to note that, hydrogen is a colourless and odorless gas. These colours are just a means for classification.
Green Hydrogen
One colour is the most sought-after among all of them today, green. In other words, hydrogen electrolysed from water using renewable energy is known as green hydrogen. Mind well, all hydrogen isn’t GREEN hydrogen. Most of the hydrogen produced today is grey hydrogen, which is extracted from natural gas in a process that requires a lot of energy and emits vast amounts of carbon dioxide. Though there are various ways to produce Hydrogen, the one above isn’t the most effective, but unfortunately the most used.
The most popular process used to produce green hydrogen is electrolysis. Electrolysers are used to split water into oxygen and hydrogen using electric energy. One specific characteristic that makes hydrogen energy so popular is the reversibility. Hydrogen can be used to produce electricity in a similar way that electricity can be used to produce hydrogen. This system is called fuel cells. As of today, the conversion process is not very efficient. It is about 60%, but it is improving rapidly.
Another crucial application of hydrogen energy is storage. Using surplus energy from renewables to produce green hydrogen is a genuine use case. For instance, during the parts of the year when the sun shines bright, or the wind blows strong, generating more power than the demand. We can use the surplus electricity to produce and store green hydrogen. The stored hydrogen then can be distributed for off-grid applications or used to convert back to electricity during peak demand. This offsets the seasonality of renewable sources and helps stabilise the grid.
With such exciting possibilities, isn’t green hydrogen the obvious way forward? In an ideal world, YES.
Should green hydrogen replace all conventional fuel applications?
Green hydrogen can be used to replace all conventional fuel applications, but that does not mean it should be. The fact is that hydrogen will be in direct competition with electric options, which are likely to be lower-cost, convenient, and safer. Storage, distribution infrastructure and efficiency are some challenges which require a lot of investment, engineering breakthrough and time to be carefully tackled.
At present, hydrogen makes a strong case for some hard to decarbonise use cases like cement and steel manufacturing, aviation, shipping, fertilisers and so on. In fact, EIT InnoEnergy is leading the way with European Green Hydrogen Acceleration Center (EGHAC) to support the decarbonisation of such hard to abate sectors. EGHAC focusses on early-stage green hydrogen projects, providing a safe environment to nurture the growth of technology. The access to such initiatives is one of the major highlights of my studies with EIT InnoEnergy.
Hydrogen has certainly wonderful possibility. The fate of its role in the clean energy future relies heavily on research, innovation and efficiency improvements that will strengthen its use case against the competition with green electricity. There is a lot of ground-breaking work happening and even more is yet to be done. Despite all these arguments, there is no denying the fact that hydrogen is an important piece of the clean energy future. How large that piece will be, is yet to be unraveled.
by Praneet Daspute, EIT InnoEnergy Master School student
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