Introduction
Hydrogen makes up about 90% of all atoms [1] in the universe. It holds the top spot on the periodic table as the lightest known element, and is colourless, odourless and tasteless. A gas at room temperature, hydrogen manifests only as a liquid in the extreme chill of minus 253 degrees Celsius [2].
Despite being the most abundant element in the universe, it is not readily available in large quantities on Earth. Here, it is primarily found bonded with other elements, such as in water (H2O), ammonia (NH3) and hydrocarbons like coal, natural gas and oil [3]. The fact that it takes energy to separate hydrogen from those other compounds highlights a key challenge in making hydrogen a viable energy source [4].
Currently, hydrogen plays a big role in the decarbonisation of the energy sector and achieving net-zero emissions. Because energy efficiency, electrification and renewables can achieve 70% of the mitigation needed, hydrogen will be needed to fully decarbonise the remaining, hard-to-abate sectors. These include heavy industry, long-haul transport or seasonal energy storage, which find it difficult to lower their greenhouse gas emissions due to the high quantities of energy required, making electrification a non-viable option.
However, the environmental impact of hydrogen hinges on its production method. By the end of 2021, the majority of global hydrogen production relied on fossil fuels: approximately 47% from natural gas, 27% from coal, and 22% from oil (as a by-product), all of which contributes to emissions and pollution. In stark contrast, only around 4% was generated through electrolysis, which can be powered by renewable energy sources. This distribution highlights a critical challenge: to find renewable ways to produce this necessary hydrogen, which, as talked in the previous, qualifies as sustainable energy. [5]
The main use of hydrogen is as an alternative fuel used in transport to power cells in vehicles, domestic production and in the industrial sector as fuel for thermal processes. One major advantage of this fuel is that when used in a fuel cell coupled with an electric motor; hydrogen is two to three times more efficient than an internal combustion engine running on gasoline and, in addition, only generating water vapour as emission, making it a zero-emission alternative [6].
Types of hydrogen based on their production method and sources
There are different ways to produce hydrogen. Depending on its source and process, Hydrogen is categorized in a broad colour range but three are the most frequent: grey, blue and green.
Grey hydrogen is referred to as the one that is produced by fossil fuels like natural gas or coal. It accounts for 95% of the hydrogen produced in the world. The two main production methods are steam methane reforming and coal gasification. In the production of this type of hydrogen, carbon dioxide is released into the atmosphere, which leads to global heating.
Another colour, blue hydrogen, is also produced from fossil fuels and with the same methods but most of the CO2 emissions are sequestered using carbon capture and storage, so the climate change impact is reduced [7].
Green hydrogen is produced from electricity from renewable sources, which results in very few or no greenhouse gas emissions. For this reason, green hydrogen is a major focus of energy transition policy. The main method used to produce this type of hydrogen is electrolysis, where water is split into oxygen and hydrogen.[1] Other less established methods that can be used to produce clean hydrogen include biomass gasification, biomass-derived liquid reforming, solar thermochemical hydrogen, photoelectrochemical, photobiological and microbial biomass conversion [8].
What hinders green hydrogen?
Among the three main types of hydrogen, it is clear that green hydrogen is preferred due to its minimal emissions and its production from renewable, clean, and abundant sources. However, why hasn’t green hydrogen yet replaced grey or blue hydrogen?
Various obstacles hinder green hydrogen from fully benefiting the industrial sector, such as high costs, technical challenges, policy issues, low demand, and the risk of carbon leakage. Policymakers can implement industrial policies to tackle these barriers and encourage or mandate a shift away from fossil fuel reliance in sectors that are difficult to decarbonize [9].
Future of green hydrogen
In 2030, annual production of low-emission hydrogen could reach 38 million tonnes (Mt) if all announced projects are realized. However, 17 Mt of this total comes from projects in early stages of development. Notably, the potential production from announced projects is 50% larger than what was projected in the IEA’s Global Hydrogen Review 2022. Only 4% of this potential production has received a final investment decision, representing a doubling since last year (reaching nearly 2 Mt). Of the total, 27 Mt will be produced through electrolysis and low-emission electricity (Green hydrogen), while 10 Mt will rely on fossil fuels with carbon capture (blue hydrogen) [10].
Relevant policies
The EU knows the importance of green hydrogen as a key energy to achieve the green deal targets. That is why the European Commission has also created a few policies to promote the use of green hydrogen, here’s a brief summary:
- The hydrogen strategy plan was adopted in 2020 to support investment, production and demand, create a market and infrastructure and promote research and international and national cooperation of hydrogen [11].
- The REPowerEU is a response to the hardships and global energy market disruption caused by Russia’s invasion of Ukraine with the main objectives of saving energy, diversifying energy supplies and producing clean energy, where hydrogen is a big part in achieving these goals. [12]
- Furthermore, the Fit-for-55 package, introduced in July 2021, includes legislative proposals that operationalize the European hydrogen strategy, creating a tangible framework for European hydrogen policy [6].
Hydrogen and HYIELD
HYIELD, thanks to the support of the European Commission and the previous policies, is offering a solution to accelerate low-carbon hydrogen production by addressing an opportunity to convert waste into clean H2. Unlike most green hydrogen production methods that use electrolysis, HYIELD utilizes biomass gasification. This involves producing clean hydrogen from the gasification of waste and organic material. This approach addresses two significant challenges: clean waste disposal as the population grows and the difficulty of decarbonising certain sectors.
The project will deploy a robust multi-stage steam gasification and gas separation process offering advantages like having feedstock flexibility, lowering the cost of production, scalable design, improving the efficiency and having an H2 purity output.
To continue the conversation on sustainable energy, upcoming articles will cover advances in hydrogen production methods and explore the utilization of waste for helping to decarbonize hard to abate sectors decreasing not only the impacts during hydrogen production but also promoting clean waste management.
References
[1] Grochala, W. First there was hydrogen. Nature Chem 7, 264 (2015). https://doi.org/10.1038/nchem.2186
[2] https://www.ehs.harvard.edu/sites/default/files/hydrogen_gas_fact_sheet.pdf
[3] https://www.nrel.gov/docs/fy22osti/82554.pdf
[4] https://www.fchea.org/hydrogen
[5] https://www.irena.org/Energy-Transition/Technology/Hydrogen
[6] https://afdc.energy.gov/fuels/hydrogen-basics
[7] https://energyeducation.ca/encyclopedia/Types_of_hydrogen_fuel
[8] https://www.energy.gov/eere/fuelcells/hydrogen-production-processes
[9] https://www.irena.org/Energy-Transition/Policy/Policies-for-green-hydrogen
[10] https://www.iea.org/reports/global-hydrogen-review-2023/executive-summary
[11] https://energy.ec.europa.eu/topics/energy-systems-integration/hydrogen_en#investing-in-hydrogen
[12] https://commission.europa.eu/strategy-and-policy/priorities-2019-2024/european-green-deal/repowereu-affordable-secure-and-sustainable-energy-europe_en
Writer: Zoe Cardell
Editorial: Lucía Salinas
October, 2024