The exciting field and growing era of renewables, as well as new developments around the field of energy, introduces a particular energy carrier, which rightly so has been gaining impressive traction: hydrogen. Its being talked about by scientists, engineers, politicians, news outlets and a large amount of professionals around the world. It might be that your country or a group of people you find interesting have made some investments or discussed the role hydrogen is playing now and in the future – but what different types of this energy carrier are there based on their production methods, and which one could help push us towards the green shift?
Figure 1: Hydrogen may provide a solution towards the green shift for eceonomies around the world.
Hydrogen has a long history, which is exciting, but also has some points that is tragic and difficult to talk about. The Hindenburg disaster in 1937 was a tragic event and in the aftermath, a lesson that safety around the use of hydrogen is important. But then again, improvements have been made and the fields of science and engineering as well as the society as a whole, have come a long way in strengthening security and regulate the work that is carried out around this extraordinary substance.
Overall, it can be said that with investments, infrastructure, scientific breakthroughs in technology and a focus towards the green shift to compliment electric vehicles, while at the same time extending a helping hand to renewable energy sources, can bring about a powerhouse that brings in income, development, jobs and much more. While electric vehicles and electrification of important industries around the world take an important role that provides electricity to households themselves, hydrogen might have an impact on the larger supply chain with ships, vessels and large trucks before taking on the greater household market.
Figure 2: Hydrogen may offer cleanliness to the environment as well as other benefits, that may also be remarkably profitable. Photo by jplenio from Pixabay.
Hydrogen and its use as an “energy carrier” means to say that the energy in simple terms can be stored – and at the same time having the ability to be carried, transported, conveyed or exchanged. The types of energy carriers vary on several dimensions, including density, ease of transport, ease of storage, cleanliness to the environment, their phases of gas, liquid and solid and more [1]. Storage and transportation are certainly some key factors to validate the viability of the energy carrier. Examples of energy carriers include hydrogen, electricity, biomass, ammonia and fossil fuels or hydrocarbons. Some energy carrier-types may be easier to transport and store, and some may introduce problems. Most of them require an infrastructure, where electricity and fossil fuels have one that is heavily utilized around the world. Hydrogen, ammonia and biomass on the other hand seem to require some further growth in the area of infrastructure. While discussing hydrogen, the mentioned energy carrier green ammonia will be another one of importance in the green shift.
To avoid confusion, hydrogen and ammonia can also be used as source of energy or fuel. Hydrogen can be used as fuel through fuel cells, where hydrogen and oxygen is converted into water. Respectively, ammonia can be used for long-haul shipping. However, this type of energy is not direct energy such as wind energy or solar energy, and it is has been attained in the form conversion from another type of energy. At the same time, hydrogen and ammonia can be used for energy storage, that can then be used later, in a similar wat that fossil fuels or batteries are used.
Types and Colours of Hydrogen Production
There are different types of hydrogen being produced today, coming in different so-called “colours” or “shades”. The ones that have been discussed in this article are four; grey hydrogen, turquoise hydrogen, blue hydrogen and green hydrogen. Depending on different shades and colours, you may also hear about black hydrogen, brown hydrogen and more. Grey, black and brown hydrogen are considered to be environmentally damaging through releases of CO and CO2. Another colour is pink hydrogen, which is produced using the electricity from nuclear energy to split water through electrolysis into hydrogen and oxygen [2]. There may be further differentiations of different shades and colours of hydrogen, depending on industries, locations around the world, availability as well as scarcity of certain resources and the different types of industries, companies and regulatory organs that are working on that particular infrastructure and technology.
Figure 3: A diagram showing four key colours or types of hydrogen, namely grey, turquoise, blue and green hydrogen.
The short answer to which one we need to thrust ourselves far into the green shift and in a stable manner, out of all these different types, includes all of the hydrogen colours that are carbon neutral if possible – we do need several of these, rather than relying on the one that could have the most positive impact on the environment, such as green hydrogen, or the one that could be the most practical in terms of infrastructure, such as blue hydrogen. In terms of the practical carbon neutral types, blue hydrogen finds itself at the top. This is due to the oil and gas industry, or industry that is somewhat related to this, having their available infrastructure to produce hydrogen using steam reforming making it cost less and take less time than other green energy carrier solutions.
Over 90% of the hydrogen that is produced around the world is prdouced as grey hydrogen as of 2021 [3], and for shifting this into blue hydrogen, takes less effort than building a different type of infrastructure. Green hydrogen is heading in the direction of the green shift with a very healthy and clean end product. With the help of companies, including those that have had a foothold in oil and gas, may act as so-called “cornerstone investors”, reliable investors that have become sizable or sometimes even multinational companies. Having these on the side of new or existing renewable energy companies, or other energy companies, may give green hydrogen the boost it needs to create and increase production of hydrogen in a green manner.
However, although there are different types of hydrogen colours, what stands apart from other energy carriers or solutions is hydrogen’s general scalability – through the use of tanks to hold hydrogen gas or sufficiently sized fuel cell batteries that can fit into fuel cell electric vehicles (FCEVs), these can be scaled in the the supply chain through gas stations for land-based vehicles and maritime vessels and ships, but also perhaps other transport areas as well.
Green Hydrogen
Green hydrogen, which is also called “clean hydrogen” on a wide basis, is produced using renewable sources wherein electricity from these sources split water into hydrogen and oxygen. The process is known as electrolysis, which has been around since the 1800s [5]. It is indeed a long way back, and it is broadly used in today’s industry and fields of technological and scientific expertise, being used all over the world for different applications: making products, refining metals, hydrogen production and more. Berlevåg municipality, situated North of the Arctic circle in Norway, is an example of a location where green hydrogen and green ammonia will be produced as part of a circular economy. It shows that even a small, not so populated area and society, can do great efforts to move itself into the green shift.
Electrolysis is the process in which a chemical reaction is started off through electricity – the flow of electrons. Direct current runs through water, where ions in the water gain and release charges at the electrodes. Cathode is the negative electrode that positive cations are attracted to and anode is the positive electrode that negative ions are attracted to, which is the opposite way of flow from the galvanic cell.
Figure 4: Green hydrogen is produced through water that is split using electrical current from electrolysis. Other by-products are oxygen and heat.
Turquoise Hydrogen
In the talk of turquoise hydrogen, it is seen as another method to work towards carbon neutrality. Turquoise hydrogen utilizes heat together with hydrocarbons, instead of using steam reforming like grey and blue hydrogen [6]. This in return creates carbon dioxide amongst other substances, as well as solid carbon. In the use of carbon from biomass, this method of hydrogen production could potentially be carbon negative as well.
Figure 5: Turquoise hydrogen is produced through heat produced with electricity and fossil fuels in a process which is known as pyrolysis, where carbon is stored in solid form.
Blue Hydrogen
Blue hydrogen has an existing infrastructure and uses steam reforming through water and hydrocarbons where carbon dioxide is captured, then stored, to create blue hydrogen. Although this method is pragmatic and has its benefits in its approach, it the blue hydrogen idea has fell to backlash over a study that mentions the unfortunate high risk in the release of CO2, which has to do with the capture and storage of CO2 in the carbon capture and storage (CCS) supply chain, where CO2 from wells and other equipment can leak into the atmosphere from the methane that is used [7]. The study comes from the US and details a greenhouse gas footprint that is 20% higher than compared to burning natural gas and coal on its own.
Nations and industries around the world have transitioned into blue hydrogen and green hydrogen, having in mind that blue hydrogen could be part of the transitionary phase into the green shift [6]. Expensive investments have been made around the world, both in public and private sectors, including, but not limited to US, UK, Netherlands, Norway, Australia and Japan. However, this study might be different for different industries, where some technologies could be ahead of others, or it could be that companies elsewhere may figure out a solution that reduces the release of such high amounts of CO2.
Figure 6: Blue hydrogen is produced through water and steam reforming of fossil fuels, where CO2 is captured and stored through.
Grey Hydrogen
Grey hydrogen is created using steam reforming to split hydrocarbons into carbon dioxide, which is released into the atmosphere, thereby not being environmentally friendly. It is, atleast for now, the most common method of producing hydrogen, but with more methods being developed, the grey hydrogen production around the world, might decrease drastically.
Figure 7: Grey hydrogen is produced through steam reforming of fossil fuels, where CO2 is released into.
Ammonia Together With Green Hydrogen
In addition to green hydrogen, there is ammonia, which can be an essential source of energy carrier in similar means. The reason that ammonia is gaining traction in this green shift or around green hydrogen is due to the transport and supply chain capabilities that comes from ammonia’s use around the world, where hydrogen for instance can be converted into ammonia [5]. Ammonia is in many instances being used as fertilizer or nutrient that can be added to the soil. In conjunction with this and other uses of ammonia, ammonia is a big part of water industry, and particularly biological or secondary treatment. The bacteria or bugs can then eat these and grow, which then results in a higher amount of ammonia that has to be removed from the waste water running to outfall.
Ammonia is stable, but reactive, and all in all a great source to make long-haul transport green by using it fuel [8]. If used based on the right safety measures, which is true in most instances, ammonia can be used as fuel and energy storage that potentially could bring a massive positive environmental and green impact into this world.
Figure 8: Green hydrogen and ammonia can be utilized as a source of energy or fuel, where another conversion from green hydrogen can produce ammonia.
Could Green Hydrogen and Ammonia Be The Ultimate Goal?
Green hydrogen is a very exciting form of energy carrier. It cuts out and does not involve polluting chemicals in its entirety, at least in terms of the ideal scenario. It requires water and electricity, which in return creates valuable hydrogen by utilizing the method of electrolysis. The green hydrogen infrastructure is unfortunately at the current time under-developed, but this development is ongoing and being brought forward around the world.
Sources
[1] ScienceDirect, 2021. Energy Carrier. Available [Online]: https://www.sciencedirect.com/topics/engineering/energy-carrier
[2] H2 Bulletin, 2021. Hydrogen colours codes. Available [Online]: https://www.h2bulletin.com/knowledge/hydrogen-colours-codes/
[3] CertiHy Canada inc., 2021. What is the difference between Grey, Blue and Green? Available [Online]: https://www.certifhy.ca/Green%20and%20Blue%20H2.html
[4] European University Institute, 2021. Between Green and Blue: a debate on Turquoise Hydrogen. Available [Online]: https://fsr.eui.eu/between-green-and-blue-a-debate-on-turquoise-hydrogen/
[5] Tinmar, 2017. Electrolysis – The Way of the Future. Owlcation. Available [Online]: https://owlcation.com/stem/Electrolysis-The-Way-of-the-Future
[6] Power Technology, 2021. What colour is your hydrogen? A Power Technology jargon-buster. Available [Online]: https://www.power-technology.com/features/hydrogen-power-blue-green-grey-brown-extraction-production-colour-renewable-energy-storage/
[7] Recharge News, 2021. Blue hydrogen ‘worse than gas for the climate’: landmark study’s damning verdict. Available [Online]: https://www.rechargenews.com/energy-transition/blue-hydrogen-worse-than-gas-for-the-climate-landmark-studys-damning-verdict/2-1-1051084
[8] Favresse et al, 2017. Preanalytics of ammonia: stability, transport and temperature of centrifugation. Available [Online]: https://www.degruyter.com/document/doi/10.1515/cclm-2017-0751/html
[9] Røkke, Nils Anders, 2020. Hva er egentlig grått, grønt, blått og turkis hydrogen? SINTEF. Available [Online]: https://www.sintef.no/siste-nytt/2020/hva-er-egentlig-gra-gronn-bla-og-turkis-hydrogen/
