The basics of hydrogen – an introduction
The climate crisis is the greatest challenge of our time. Meeting the goals set by the Paris Agreement will require net zero CO2 emissions globally around mid-century and net zero emissions of all greenhouse gases shortly thereafter. In the near term, global greenhouse gas emissions need to be halved by 2030. [1] This will require a massive transformation in how we run our economy and develop our societies.
Hydrogen has for decades been highlighted as a source of clean energy that could enable the abandonment of fossil fuels. Thanks to technological innovation, the time when the abundant gas can aid in the fight against climate change could finally be here. All types of hydrogen are not, however, sufficient for powering a sustainable society. To maximize the environmental gains, it must be produced with low, if any, greenhouse gas (GHG) emissions, resulting in the type of hydrogen often referred to as green hydrogen or low-carbon hydrogen.Green Hydrogen has several properties that makes it highly attractive as a substitute for fossil fuels, but it needs to overcome several hurdles before becoming an integral feature in our everyday lives. Not least, it needs to be shown that it could be produced at an industrial scale at a competitive cost. In addition, questions regarding distribution, storage, and industrial use remain.But with hydrogen’s promising future as a backdrop, finding solutions to these challenges offer huge opportunities for companies striving to come out on top in the race to conquer hydrogen.
What is hydrogen?
Making up roughly 75 percent of all normal matter in the universe, hydrogen (H) is by far the most abundant chemical element. In normal conditions, isolated hydrogen is a gas of molecules that consists of two hydrogen atoms (H2) that are colorless, odorless, tasteless, and non-toxic. Because of its reactive nature, hydrogen is not found free in nature, but rather as a part of a molecule, such as water (H2O). Hydrogen has very high energy for its weight, but very low energy for its volume. During the later stages of the 18th century, it was found that hydrogen produces water when burned, the property for which it was later named: in Greek, hydrogen means “water-former”.What is hydrogen used for?
In 2019, approximately 70 million tonnes of hydrogen were produced through dedicated production, 76 percent from natural gas, and 23 percent from coal. Its primary use was for oil refining (33 percent), ammonia production (27 percent), methanol production (11 percent), and steel production through direct reduction of iron ore (3 percent) [2]. While representing only a small share of all hydrogen used, NASA has for decades relied on hydrogen gas as rocket fuel to deliver crew and cargo to and back from space.As virtually all hydrogen used today is supplied by fossil fuels, switching to low-carbon production technologies offers significant decarbonization opportunities. In addition, as many of the sectors that account for the largest hydrogen demand today are growing, the opportunity to make use of low-carbon hydrogen further increases. For example, hydrogen demand in the chemical sector is expected to grow by 31 percent between 2019 and 2030 [3].For hydrogen to make a significant contribution to clean transitions, it needs to be adopted in sectors – including transport, industrial applications, buildings, and power generation – where it's currently almost absent.Heavy transport, such as aviation and shipping, have limited low-carbon fuel options available, representing an attractive opportunity for hydrogen-based fuels. For lighter vehicles, such as passenger cars, hydrogen is facing the challenge of having to compete with other low-carbon options, such as battery-driven electric vehicles. The competitiveness of hydrogen fuel cell electric vehicles depends largely on fuel cell system costs, the construction and build-up of refueling stations, and accessibility to affordable green hydrogen.One of the many promising industrial uses of hydrogen going forward is as a reduction agent in the iron and steel industry. Hydrogen is expected to enable these industries, which collectively account for about 7 percent of global CO2 emissions [4], to significantly reduce their emissions. Green hydrogen could be used to replace traditional blast furnaces that use coal to reduce iron, replacing CO2 emissions with water and reusable heat. The International Energy Agency highlights that it would be technically possible to primarily produce all steel with hydrogen, but it would require vast amounts of renewable electricity and overcoming challenges related to scaling the production.Hydrogen also presents an opportunity to reduce emissions in power generation. In the near term, hydrogen could be used to produce ammonia which in turn could be co-fired with coal-fired power plants. In the longer term, hydrogen could play a role in large-scale and long-term storage to balance seasonal variations in energy demand and supply.Why would you use hydrogen instead of other solutions?
Hydrogen has several properties that makes it an attractive source of power. Low-carbon hydrogen is currently the only feasible option for cleaning up some of the world’s largest polluters, including steel and fertilizer industries. These industries are essential to our way of life, both today and in the future, but decarbonization is a must. Even in industries with other low-carbon fuel options, hydrogen can be an attractive alternative due to it being abundant, non-toxic to the environment, dissipating easily, and storage possibilities, which in the future could enable clean energy to be shipped across oceans and for large distances.Is hydrogen dangerous?
There are decades of experience using hydrogen for industrial purposes, including distribution networks and storage able to manage any safety challenges. But with increased production, distribution, and use of hydrogen, new challenges arise that need to be addressed to mitigate risks associated with the power source. Like other energy carriers, hydrogen present certain health and safety risks when used in a large scale. As a light gas of small molecules, its storage requires special considerations to prevent leakages. However, there is considerable potential in blending hydrogen into the natural gas infrastructure for storage and distribution despite these issues.Hydrogen is non-toxic but highly flammable. Its flame is not visible to the naked eye, and it is both odorless and colorless – making it difficult to detect fires and leakages. It has a high flame velocity, broad ignition range, and low ignition energy – attributes partly offset by the fact that hydrogen dissipates quickly. Still, these risks are addressed in current and future hydrogen infrastructure to prevent leakages and fires.Is hydrogen sustainable?
Whether hydrogen is sustainable or not depends on the method of production. As many current methods use fossil fuels to produce hydrogen, they are also causing greenhouse gas emissions. But – using ”non-green” hydrogen could still be a better alternative than other sources of fuel, even if it is not sustainable in itself. If hydrogen is produced with inputs that are sustainable, such as renewable electricity, it is considered a sustainable fuel as it gives rise to no, or very limited quantities of greenhouse gas emissions.How is hydrogen produced?
There are several different methods for producing hydrogen. What the hydrogen is called is largely dependent on the technique used for producing it. For example, black hydrogen (or brown, depending on the type of coal used) is produced using coal, causing large amounts of carbon dioxide. Grey hydrogen, which today is the most common in the market, is produced from natural gas in a process that produces 10 kilograms of CO2 for every kilogram of hydrogen [5].The production method for blue hydrogen is like grey hydrogen, but uses carbon capture, utilization, and storage (commonly called CCUS) to decrease its emissions. There is currently no technology to capture and store all the CO2 resulting from the production of blue hydrogen. Another way to produce hydrogen is by using electricity to split water into hydrogen (H2) and oxygen (O2) through electrolysis. The emission from the process depends on the source of electricity. For electricity sources that do not emit greenhouse gases, it’s possible to create hydrogen without greenhouse gases. This is the technology that H2 Green Steel will use in its hydrogen production.