On celebrating International Hydrogen and Fuel Cells Day, we debunk 3 myths about hydrogen that still raise doubts about its attractiveness as a new fuel in the global economy.
For several years, we have celebrated International Hydrogen and Fuel Cells Day on 8 October. With good reason. In international nomenclature, the date aptly refers to the atomic mass of this unique element (1,008). Year after year, the popularity of hydrogen as the fuel of the future is growing. Despite growing public and industry awareness, myths are still perpetuated in the public debate, intensifying fears about its widespread use. Today, we want to take up some of them and convince you that hydrogen is not as scary as they portray it to be.
Myth 1. Hydrogen is too explosive and dangerous to be widely used
This is the most frequently repeated myth about hydrogen. We make no secret of the fact that we have addressed the subject of its explosiveness more than once. After all, the safety of the technology is a key aspect for us (you can read more about it here). But from the beginning…
We have long stressed that hydrogen is neither more nor less dangerous than the hydrocarbon fuels that have been widely used for years. However, it differs from them in certain characteristics. It is their in-depth understanding that will enable the fuel to be used widely in an informed and safe manner.
It is an undeniable fact that when it comes to design and safety, hydrogen remains a challenging fuel. Under standard conditions (temperature and pressure), it takes the form of an odorless, colorless gas and is approx. 14 times lighter than air, which makes it float quickly in open space. On the one hand, this is a challenge for designers, as leaks from the system are not easily detectable by the human senses and the small size of hydrogen molecules contributes to its penetration through materials and the formation of the so-called hydrogen embrittlement phenomenon. On the other hand, we can consider the diffusivity of hydrogen as a significant advantage of the new fuel. In the event of a malfunction and release, it will quickly rise and disperse in open space, so that it will be diluted in the air relatively quickly.
This is particularly important from the perspective of the flammability range of hydrogen. Its ignition occurs if its content in the air is below the Upper Flammability Limit (UFL) and above the Lower Flammability Limit (LFL) and if, in addition, there is a catalyst as an ignition source, e.g. in the form of a spark. Undoubtedly, the flammability range for hydrogen is much wider than for other fuels and is about 4-77% in a mixture with air, with an even wider range in a mixture with pure oxygen. One form of protection against uncontrolled fuel combustion is the elimination of potential ignition sources (catalysts). It is the proper design of the installation and the selection of components, as well as careful management of hydrogen, that ensures that it does not present a higher risk than other hydrocarbon fuels, the use of which, as is often forgotten, also requires compliance with certain safety standards and norms.
Myth 2. Hydrogen is a green and renewable fuel
This is a particularly tricky myth. Not because it is untrue, but because it is often wrongly used in debates as a promotion of hydrogen from conventional fuels. While the combustion of hydrogen itself can be seen as environmentally friendly (it contains no carbon or sulfur, and CO, CO2, SOx, soot, and other particulates are not produced during combustion), the source of the fuel remains a key issue in terms of its designation as green. Currently, about 96% of global hydrogen production is based on conventional fuels, mainly natural gas, and coal, and is dominated by a method called Steam Methane Reforming. According to estimates, hydrogen produced in this way (grey) could be responsible for global emissions of up to 830 million t CO2e per year, thereby worsening environmental problems.
Solutions to this problem include the use of carbon capture and utilization (CCUS) methods, the application of which in the production of hydrogen from fossil fuels (in this case referred to as blue) is expected to significantly reduce emissions – depending on the technology by 50-90%. However, in 2021, in the “How green is blue hydrogen?” report, researchers at Stanford and Cornell Universities documented that when the full lifecycle of the fuel is considered, blue hydrogen production can generate up to a 20% higher greenhouse gas footprint than production without considering CO2 capture. One of the reasons for this is the need for additional energy to drive the capture apparatus.
Renewable hydrogen will therefore only be hydrogen that has been produced using energy from RES. In colloquial nomenclature, it is referred to as green hydrogen. It is produced by the electrolysis of water in special devices called hydrogen generators or simply electrolyzers. If energy from renewable sources – solar, wind, or hydro – is used in the process, the result is an emission-free fuel throughout its production and operation chain.
Myth 3. The production of renewable hydrogen requires too much energy and financial input to call it an efficient and attractive fuel
Energy can be converted from one form to another, with the conversion always being associated with the creation of certain energy losses. This applies not only to the conversion of electrical energy into chemical energy of hydrogen by electrolysis and vice versa but even to conventional fuels.
On average, about 9l of water and about 55-65 kWh of electricity are needed to produce 1kg of hydrogen by electrolysis, with the efficiency strictly dependent on the technology used. Currently, the most promising electrolyzer types include alkaline electrolyzers, polymer electrolyte membrane electrolyzers (PEMs), solid oxide electrolyzers (SOECs), and anion membrane electrolyzers (AEMs). The former is characterized by the highest technological maturity and relatively low purchase and operating costs due to the absence of the need to use noble materials. PEM electrolyzers are at a stage of rapid development and commercialization. They have a simple design and faster dynamic response compared to alkaline electrolyzers, as well as a wide control range. They use platinum and iridium, making them much more expensive in terms of investment and shorter lifespan. Solid oxide electrolyzers are currently in the research and development phase, but already show particularly high efficiencies of around 80-90%.
In terms of production, the barrier to the attractiveness of hydrogen from electrolysis remains the potentially high cost of electricity (with an emphasis on renewable energy) and equipment procurement (relatively few manufacturers), and component life. It is a myth, however, that the technologies will remain too expensive to be widely deployed by the end of the decade. As forecasts prove, with market growth and economies of scale, the cost of purchasing and operating electrolyzers will decrease significantly, making carbon-free production more viable. This is all the more so as the price of renewable energy is also set to fall. One reason for this will be an increase in the number of installations related to the need to meet the 45% RES target in the total EU energy mix.
Declining prices will directly affect the cost of production and thus the price of hydrogen. For example, analyses by the Green Hydrogen Catapult coalition suggest that the price of hydrogen could be reduced to USD 2/kg by 2026, and under the ‘Earth shot’ plan, President Biden’s administration is targeting a price of USD 1/kg hydrogen by 2030*. In Europe, on the other hand, Hydrogen Europe forecasts the possibility of reaching a hydrogen price of 2 EUR/kg as early as 2030.
We make no secret of the fact that converting hydrogen back into electricity using fuel cells is fraught with significant losses, as 1 kg of hydrogen yields an average of around 16 kWh of electricity. However, as with electrolyzers, the technology used in the process is also significant. This is because different types of fuel cells are available on the market, with specific efficiencies:
- alkaline (60-70%)
- proton membrane (40-60%)
- proton membrane methanol fuelled (20-30%)
- phosphoric acid (55%)
- with molten carbonate (65%)
- solid oxide (60-65%)**.
It is worth noting that work is continually underway and entirely new projects are being announced on fuel cell technology to increase their efficiency and thus the conversion efficiency and cost-effectiveness of using hydrogen as an energy carrier and storage in various sectors and applications.
End-use hydrogen is highly efficient due to its energy density, which is 20 times that of lignite and more than 3 times that of petroleum. In addition, heat is released during hydrogen exploitation, which can also be utilized. Given the indicated fuel efficiency, which is an added value for users, it may be able to compensate for losses and conversion costs. This is all the more so because, although direct electrification would be more efficient, it is not possible in some sectors. This is particularly difficult in long-distance transport and heavy industry (metallurgy), which requires high temperatures and is energy intensive. This in turn, at current market prices for conventional energy, is no longer cost-effective.
*sciencefocus.com
**P. Grygiel, H. Sodolski, Laboratorium Konwersji Energii, 2014
