Green hydrogen is perhaps the most widely talked about energy source today, owing to its immense possibilities to revolutionise both the power and transport sectors. This growing popularity stems from its potential for deployment to serve multiple applications ranging from industrial processes, process heat, power generation and energy storage to clean mobility and many other uses. Moreover, it can completely decarbonise the energy ecosystem right from its generation to consumption. For these reasons, interest in the low-cost production of green hydrogen has skyrocketed amongst large industries such as steel and ammonia production, governments, renewable energy developers, power utilities and even major oil and gas firms. While its production is currently limited to a few pilot and research projects, it is soon expected to scale up as companies race to find the most scalable and affordable business model for producing and transporting green hydrogen.
Market size and applications
According to the World Bank’s report, “Green Hydrogen in Developing Countries”, the global hydrogen market was worth $135 billion in 2019, with over 70 million tonnes produced in that year. Further, the total hydrogen market is expected to grow at a compound annual growth rate of 8 per cent until 2023. At present, around 96 per cent of the global hydrogen comes from fossil fuels, with only 4 per cent from electrolysis. Thus, there is a huge potential for transitioning from fossil fuel-based blue or brown hydrogen to renewable energy-powered electrolyser-based green hydrogen. Rightly, the first and foremost application of green hydrogen is to replace the existing conventional hydrogen feedstocks, especially in industrial uses. For instance, green hydrogen can be put to use in oil refining, ammonia production and in steel making for removing oxygen from the iron ore. In addition, green hydrogen can be used instead of natural gas or blended with it in colder countries for decarbonising residential and commercial heating systems. However, using hydrogen will make commercial sense only at places where natural gas prices are high.
So far, power systems find the most keenly explored applications of green hydrogen. It can be burnt and used in existing coal or gas power plants as a lower-impact substitute. However, the more popular use case for green hydrogen is as a substitute for battery-based energy storage or natural gas to maintain grid stability. With solar and wind power penetration increasing worldwide, green hydrogen can help in addressing the intermittency issues of these renewable sources by providing power when solar and wind are unavailable. Further, when there is excess solar or wind power, which cannot be integrated into the grid, it can be used to generate green hydrogen. Thus, this curtailed wind or solar power can be used to make green hydrogen at virtually no additional cost.
The advantage of hydrogen is that it is suitable for long-term storage of renewable electricity, for instance, in salt caverns or even seabeds. This can be then put to use when solar and wind generation is low, especially in winters. In addition, to achieve economies of scale, the use of offshore wind power to produce green hydrogen is being explored with great interest by many energy majors in Europe. The growth in offshore wind power has been quite significant in the continent resulting in the low cost of abundant renewable power that can be used for the production of green hydrogen through electrolysis.
Another broad application of green hydrogen is for powering fuel cell vehicles and replacing gas as an automotive fuel in many parts of the world. The efficiency of fuel cells is much higher than that of the internal combustion engines, which means the same quantity of hydrogen can transport over longer distances than gas and the only emission in the process is water. Thus, hydrogen is particularly well suited for heavy transport options like buses and trucks than cars, which are already moving towards battery-based electric vehicles. Moreover, hydrogen filling stations can be set up in a similar manner as conventional gasoline stations. Green hydrogen is also being tested for use in shipping and aviation, two other fuel-intensive transport segments. Moreover, hydrogen fuel cells are grid independent, and can be used for powering various critical load functions like data centres, telecommunications towers, hospitals, emergency response systems and even military applications for national defence.
While green hydrogen has benefits across the energy value chain, there are still many challenges in its commercial-scale production. The biggest issue is related to the cost as electrolysers are quite expensive compared to the steam methane reforming method of producing blue hydrogen using natural gas. However, it is expected that in due course of time technological innovations and research will make electrolysers more affordable, as in the case of solar panels and battery energy storage.
Meanwhile, another key challenge for hydrogen to replace conventional fuels in existing power plants is that various aspects of these plants including turbines, pipes and steel containers will have to be redesigned. Carbon fibre coatings will have to be applied on existing gas pipelines and containers for storage and transportation to prevent leakage or brittleness of metals. Moreover, hydrogen gas is highly flammable and needs to be handled carefully to prevent explosions. The current American Institute of Aeronautics and Astronautics’ (AIAA) standard for hydrogen safety guidelines is AIAA G-095-2004, the Guide to Safety of Hydrogen and Hydrogen Systems, which cover both the risks and methods to ameliorate them.
Despite the current high costs and handling problems, the potential of green hydrogen in the decarbonisation of energy systems cannot be ignored. Its wide variety of applications, combined with the knowledge that it can be transported over long distances, can be stored for a longer time and that it is a clean fuel have made it the fuel of choice for the near future. Moreover, with renewable power prices becoming cost-competitive in most geographies, the case for green hydrogen becomes even stronger.
By Khushboo Goyal