Green hydrogen is one of the great promises of the energy transition, as it offers a way to store and use energy without carbon emissions. This type of hydrogen is produced through a process called electrolysis of water, which separates hydrogen and oxygen using electricity generated by renewable sources such as solar and wind. Despite its benefits, green hydrogen faces a series of challenges that we must be aware of in order to assess its potential as a genuine alternative to Fossil fuels.
In this article, we explore the key issues affecting the development of green hydrogen, along with its features, advantages and drawbacks, to get a complete overview of what this technology really offers.
green hydrogen production
Hydrogen is not usually found in isolation in nature, but is often associated with other molecules, such as water. In electrolysis, we apply an electric current to break up water molecules (H2O) into hydrogen (H2) and oxygen (O2). This process is only sustainable if the electricity used comes from clean sources, such as solar or wind energy. This is why the hydrogen produced using this technique is called green hydrogen.
In contrast, most of the hydrogen currently produced comes from Fossil fuels, such as natural gas or oil. This type, known as grey hydrogen, is widely used in the chemical industry and in refineries. However, its production generates large amounts of carbon dioxide (CO2), which makes it environmentally unsustainable.
Although much progress has been made in the production of green hydrogen, it is still a relatively new technology and is far from scalable. Worldwide, 99% of hydrogen used still comes from fossil fuels, resulting in annual global emissions of 900 million tonnes of CO2.
energy storage
One of the most important characteristics of green hydrogen is its ability to store energy. Renewable energies, such as solar and wind, are Intermittent, which means that sometimes they generate more energy than can be consumed and other times they do not generate enough.
Hydrogen can solve this problem by acting as a storage device. When there is a surplus of renewable electricity, it can be used to produce hydrogen through electrolysis. This hydrogen can then be used as fuel in engines, machinery or even as a raw material in industrial processes. In this way, green hydrogen can help store surplus renewable energy and use it when renewable resources are scarce.
In addition to acting as an energy accumulator, green hydrogen does not produce greenhouse gas emissions when used, making it a key piece for the decarbonization industrial, transport and energy sectors.
Green hydrogen problems
The main drawback of green hydrogen is its high production cost. Although hydrogen is the most abundant element in the universe, the process of obtaining it from water is expensive due to the energy consumption required for electrolysis. Even with electricity from renewable sources, the cost remains high.
Another problem facing green hydrogen is the low energy efficiency current production and transportation methods. According to studies, approximately 80% of the energy used in the green hydrogen production process is wasted. This energy inefficiency is a major barrier to its large-scale adoption.
In addition, the transportation and storage of hydrogen are also complicated. This gas has a low energy density compared to other fuels, meaning that much larger tanks and pipelines are needed to store and transport the same amount of energy. It is also highly flammable, increasing safety risks.
Another important challenge is the risk of escapesHydrogen molecules are extremely small, much smaller than methane or natural gas, making them harder to contain. If hydrogen leaks into the atmosphere, it could affect the climate in a similar way to greenhouse gases, as it could influence levels of methane and other atmospheric compounds.
How much does it cost to produce hydrogen?
One of the most prominent barriers to the expansion of green hydrogen is its cost. A recent study estimates that green hydrogen production through electrolysis can be cost-effective from €3,23 per kilogram if renewable energy sources are used. Some optimistic forecasts suggest that within a few years costs could be reduced to €2,5 per kilogram.
However, these figures are highly dependent on several factors, such as the price of electricity and the cost of electrolysers, which for now remains considerable. Currently, producing green hydrogen is significantly more expensive than producing grey or blue hydrogen, which is why many industries continue to choose these alternatives.
El gray hydrogen is the most common and cheapest, but its production involves the burning of fossil fuels, making it an environmentally unsustainable option. On the other hand, blue hydrogen, which is obtained from natural gas but captures and stores CO2 emitted, it is an option that reduces emissions, although it is still less sustainable than green hydrogen.
Advantages
Green hydrogen has several and advantages key factors that make it a very attractive alternative for decarbonizing sectors that are difficult to electrify:
- Emission reduction: Its production and use do not emit polluting or greenhouse gases. It is a completely clean fuel when obtained through renewable energy.
- Energy storage: It acts as a solution to store surplus energy from renewable sources and release it when demand requires it, expanding the capacity of renewables.
- Wide applications: It functions as fuel in transportation, as an intermediary in energy generation and as a raw material in the chemical industry.
- Decarbonization of industrial sectorsSectors such as air transport, maritime transport and heavy industry depend on high energy density fuels that only hydrogen can offer.
Disadvantages
Despite the advantages of green hydrogen, we must also take into account the disadvantages that shows:
- High cost of production:The electrolysis process remains expensive, especially compared to grey hydrogen.
- Difficulty of transportation and storage:Hydrogen requires specific infrastructure to be stored and transported safely, which adds additional costs.
- Security risksHydrogen is highly flammable and its transportation can pose risks if not handled properly.
- Low energy efficiency: A large part of the energy invested in the production of green hydrogen is lost in the production and transportation processes.
In short, green hydrogen represents one of the most promising technologies for the energy transition and the decarbonisation of sectors that do not have a clear alternative through direct electrification. However, its success will largely depend on reducing its production cost, improving its efficiency and developing the infrastructure necessary for its storage and transport.