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Renewable hydrogen, the future of mobility?


On December 13, the Climate Summit, COP28, which took place in the United Arab Emirates, ended with the signing of a historic agreement based on a joint transition away from fossil fuels worldwide, with the internationally agreed goal of limiting global warming to 1.5 degrees Celsius compared to pre-industrial times, as agreed in Paris 2015.


On the other hand, last October 23rd was the deadline, in Spain, for applications for the development of projects related to hybrid and electric hydrogen fuel cell vehicles, in which 40 million euros were approved and where a private investment of 160 million euros was foreseen. These are national public funds approved in a Royal Decree that regulated the direct granting of aid in 2023 for innovative projects encompassing: models, systems and components related to hybrid and electric hydrogen fuel cell vehicles.


Globally, the hydrogen push continues to accelerate with more than 1040 projects announced, requiring an investment of $320 billion. Of these projects, 795 will be commissioned before 2030. For its part, supply represents approximately two-thirds of the investments announced up to 2030, of which Europe and North America account for 60% of the total volumes.


The search for more sustainable energy solutions is an imminent requirement in the fight against climate change, and in this area, the efficient workability of hydrogen is a promising development. For its part, research and development of hydrogen projects continues to increase, both in terms of the number of projects, as well as in the maturity of the ongoing projects themselves, however; "What is renewable hydrogen?", "Why is it beneficial?", "Why is its use not currently implemented and widespread?", "When will we be able to employ this technology?"


These are some of the questions that we ask ourselves at Trem, as an engineering and strategic product design studio, and that we try to focus and answer in this blog, putting the focus on a point of view centered on the mobility that could be achieved with this type of fuel.



 

Green hydrogen


Green hydrogen is a form of green hydrogen, obtained from renewable energy sources: solar, wind, etc. Which, through a process of electrolysis of water, divides it (H2O) into its basic components: hydrogen (H2) and oxygen (O2). The resulting hydrogen can be stored and used to generate electricity through a transformer process, which results in the generation of oxygen, i.e. it emits non-polluting gases to the environment and the atmosphere: CO2, NOx or PM10 and PM2.5 particles.


For the transformation of hydrogen into electricity, it is necessary the application of a system called fuel cell, which is an electrochemical device that directly transforms chemical energy into electrical energy. To do so, it is based on a fuel, hydrogen, and a comburent, mainly oxygen, which are transformed to produce water and energy in the form of direct current and heat.



Graphical diagram of how a fuel cell functions
Fuel cell. Source: Centro Nacional del Hidrógeno

In this way, hydrogen acquires a myriad of applications in various sectors of industrial design and engineering, such as mobility and transportation, stationary applications such as electricity and heat generators in infrastructures, and even power in case of emergency, and portable applications such as small electrical devices.



 

Hydrogen in mobility


In this blog, we will focus on hydrogen applications in transportation. In this area, hydrogen vehicles can be classified as follows:


Fuel cell vehicles


Fuel cell vehicles or FCEV (Fuel Cell Electric Vehicle) are those that generate energy from the fuel cell, which is usually coupled to a small battery or supercapacitor. The hydrogen (H2) is stored compressed at high pressure in a tank on board the vehicle, so that the battery transforms the hydrogen into electricity by taking advantage of the oxygen in the air to generate water.



Graphic diagram of the operation of a fuel cell vehicle.
Fuel cell vehicle. Source: Centro Nacional del Hidrógeno


Hydrogen combustion vehicles


Hydrogen combustion vehicles (H2-ICE) use alternative internal combustion engines for propulsion. In this case, hydrogen or a hydrocarbon mixture is used as fuel, which greatly reduces CO2 levels with respect to current engines.

This option avoids the production of batteries or fuel cells, so that if the fuel is 100% hydrogen, the waste generated during combustion will be water.



Graphical diagram of the operation of a hydrogen combustion vehicle.
Hydrogen combustion vehicle. Source: Centro Nacional del Hidrógeno


Hydrogen-based extended-range vehicles


Extended-range vehicles, on the other hand, are hybrid vehicles that have a battery system and, additionally, a hydrogen storage system and a fuel cell, so that they can use either one energy source or the other, or both simultaneously. They are very versatile vehicles as they can be refueled with electricity or hydrogen.



Graphical diagram of the operation of a hydrogen-based extended range vehicle
Hydrogen-based extended-range vehicle. Source: Centro Nacional del Hidrógeno


From a theoretical and ideal point of view, hydrogen seems a promising solution to current emission problems, as well as an excellent answer to fight the climate crisis, however, like other energy sources and the generation of new technologies, hydrogen presents a number of benefits, challenges and weaknesses that are set out below.


Focusing on urban mobility, and taking as a reference the main competing energy sources, i.e. diesel, gasoline and electric batteries, let's see what benefits hydrogen offers and what challenges should be faced to get the most out of this material.


Emissions from hydrogen systems


On the one hand, hydrogen offers a clean and renewable energy source for different types of vehicles and means of transport, such as that achieved with electric batteries, reducing carbon emissions, such as those from diesel and gasoline, and contributing to more sustainable mobility. This is especially interesting in urban areas, which are becoming increasingly densified and generate more emissions.


Efficiency of hydrogen systems


In addition, hydrogen vehicles offer a longer range and faster refueling times compared to electric batteries, making them ideal for urban mobility and industrial applications.


At this point, a comparison of the autonomy of the vehicles is made by us, taking as a reference the different energy sources mentioned above and similar tank volumes in terms of capacity and typical in the market:


For a diesel and gasoline tank of about 50 liters volume, a range of between 750 km and 1000 km and between 500 km and 750 km, respectively, could be obtained. For a 50 kWh electric battery, a range of 200 to 300 km could be obtained. However, the range of hydrogen cell vehicles, with a 5-liter hydrogen tank, would allow a range of 500-600 km, with charging times of less than 5 minutes, and with a hydrogen price (from renewable sources) of between 5-6 €/kg.


Hydrogen production


On the other hand, the establishment of this energy source is still a long way off, as there are many challenges that engineers and designers must face in order to make the use of hydrogen profitable and optimize it in the current paradigm.


In terms of obtaining the raw material, hydrogen requires an energy input for the electrolysis of water and a secondary transformation of hydrogen into electricity. One of the main problems in obtaining this material is the low efficiency and high cost of photoelectrochemical technology to produce hydrogen. However, recent studies at Rice University, Houston (Texas), have obtained promising results in this area, with a conversion efficiency of 20.8% using cheaper semiconductors.


Compared to electric batteries that offer higher conversion efficiencies (approximately 90%), hydrogen has a long way to go.


Hydrogen storage and transportation. Refueling points


Hydrogen faces significant challenges in terms of storage and transport of the feedstock, such as compression and liquefaction. In this area, it should be noted that hydrogen is the smallest particle in the periodic table and is therefore highly complex to store and preserve.


This not only represents a challenge in technological innovation and an improvement in the precision of current systems, but also requires investment in infrastructure and the development of optimal systems for this purpose.


At this point, it is worth mentioning the establishment of charging points for vehicles, which will need to be solved to allow the storage of hydrogen, whether in gaseous or liquid form, its correct operation, usability and interaction with the user usability and user interaction.



 

Conclusions


Hydrogen can be a clean and versatile source of energy when produced from renewable sources, however, there are still several challenges to be overcome to establish itself competitively in the market, such as optimizing its efficiency and facing the high costs in technological innovation regarding the systems for obtaining hydrogen, its storage and transportation.


Gasoline and diesel are efficient for energy storage, but highly polluting, while electricity, when generated from clean sources, is highly efficient and has low carbon emissions, making it attractive for mobile and stationary applications.


Investment, both financial and temporal in project development, will be crucial in determining the feasibility of this technology. At this point, Trem's role as designers and engineers is crucial, since we have the ability to transform innovative resources into tangible and consumable elements for all users. This not only implies launching new products to the market, but also making efficient use of technology to generate favorable scenarios for the future of people.


What do you think? Do you have any projects in mind related to renewable hydrogen?







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