Green hydrogen has become one of the basic pillars of the EU Recovery Fund. Some funds will be the largest stimulus package ever financed through the EU budget, with a total economic injection of 1.8 trillion euros used to rebuild Europe after COVID-19. The energy transition is one of the axes of this recovery, of which 30% of the budget is allocated to climate change. This is where the hydrogen Verde begins to gain status, attracting more and more interest and placing it in the public debate as one of the basic pillars of economic decarbonization. But what exactly is green hydrogen?
In this article we are going to tell you what green hydrogen is, what are its characteristics and importance.
What is green hydrogen
Hydrogen is the most abundant chemical element on earth, but it has a problem: it is not freely available in the environment (for example, in reservoirs), but it always combines with other elements (for example, in water, H2O or methane , CH4). ThereforeIn order to be used in energy applications, it must first be released, that is, separated from the rest of the elements.
To carry out this separation and obtain free hydrogen, it is necessary to carry out some processes and energy is spent on them. This defines hydrogen as an energy carrier, rather than the primary energy or fuel that many people consider. Green hydrogen is an energy carrier, not the main source of energy. In other words, hydrogen is a substance that can store energy, which can then be released in a controlled manner elsewhere. Thus, can be comparable to lithium batteries that store electricity, rather than fossil fuels like natural gas.
Hydrogen's potential to combat climate change lies in its ability to replace fossil fuels in applications where decarbonization is more complex, such as maritime and air transport or certain industrial processes. What's more, has great potential as a seasonal energy storage system (long-term), which can accumulate energy for a long time, and then use it on demand.
Origin and types of hydrogen
As a colorless gas, the truth is that when we talk about hydrogen, we usually use very colorful terms to express it. Many of you will have heard of hydrogen green, gray, blue, etc. The color assigned to hydrogen is nothing more than a label that is used to classify it according to its origin and the amount of carbon dioxide released during its production. In other words, an easy way to understand how "clean" it is:
- Brown hydrogen: It is obtained through the gasification of coal, and during the production process carbon dioxide is released. It is sometimes called black hydrogen.
- Gray hydrogen: obtained from reforming natural gas. It is currently the most abundant and cheapest production, although the cost is expected to increase due to the price of carbon dioxide emission rights. The production of 1 ton of H2 ash will emit 9 to 12 tons of CO2.
- Blue hydrogen: It is also produced by reforming natural gas, the difference is that part or all CO2 emissions are avoided through the carbon capture system. Later, this carbon dioxide can be used to make synthetic fuels, for example.
- Green hydrogen: It is obtained by electrolyzing water using electricity from renewable energy sources. It is the most expensive, but as the cost of renewable energy and electrolyzers decreases, its price is expected to gradually decrease. Another type of green hydrogen is produced from biogas using livestock, agricultural and / or municipal waste.
In fact, the green hydrogen production process is not complicated at all: electrolysis simply uses electrical current to break down water (H2O) into oxygen (O2) and hydrogen (H2). The real challenge is being competitive, which requires a lot of cheap renewable electricity (which is more or less fixed), and efficient and scalable electrolysis cell technology.
Uses of green hydrogen
In theory, one of the most effective ways to decarbonize the economy is to try to electrify the entire energy system. However, for now, battery and electrical technologies are not feasible, depending on the application. In many of them, green hydrogen can replace fossil fuels, although not all are so mature or simple:
Instead, use brown and gray hydrogen. The first step should be to replace all the fossil hydrogen currently used in industry, use developed technologies and reduce costs. The challenge is not small: the global demand for hydrogen from electricity production will consume 3.600 TWh, more than the total annual electricity generation of the EU. These are the main uses of green hydrogen:
- Heavy industry. Large consumers of steel, cement, chemical companies and other fossil fuels are not easily accessible or directly feasible.
- Energy store. This is undoubtedly one of the most promising applications for hydrogen: as a seasonal energy storage system. With the growing popularity of renewable energy, we will find that the cost of electricity is really cheap, and there will even be a surplus because there is no place to consume it. This is where hydrogen will come into play, which can be produced cheaply and then used on demand for any application, be it power generation or any other application.
- Transportation. Transport is undoubtedly another of the most promising applications of hydrogen. In today's light transport, batteries are winning the competition, but some manufacturers (especially Japan) continue to develop their fuel cell models and the results are increasingly promising.
- Heating. Domestic and industrial heating is a sector that cannot always be electrified (heat pumps are not always an option), and hydrogen can be a partial solution. Additionally, existing infrastructure (such as natural gas networks) can be used to increase demand. In fact, mixing up to 20% by volume hydrogen in an existing natural gas network requires minimal modifications to the end-user network or appliances.
I hope that with this information you can learn more about green hydrogen and its applications.