This blog post examines the technological advancements required for hydrogen fuel cell vehicles to establish themselves as eco-friendly energy and the challenges involved in realizing this.
Currently, humanity’s primary energy sources are hydrocarbons like coal and oil, and nuclear power derived from nuclear fission. Hydrocarbons pose problems of environmental pollution due to carbon dioxide emissions and resource depletion, while nuclear power has the drawback of potentially causing massive secondary environmental damage if facilities are destroyed. These problems with traditional energy sources represent one of the greatest challenges humanity faces today, urgently necessitating the search for new alternative energy sources from the perspectives of environmental and economic sustainability. In his book ‘The Third Industrial Revolution’, the renowned economist Jeremy Rifkin states the following:
“While the First and Second Industrial Revolutions relied on fossil fuels like coal, oil, and natural gas, the Third Industrial Revolution—already underway—is characterized by the production and utilization of clean energy such as hydrogen and electricity, harnessing renewable sources like solar, wind, and geothermal power.”
Interest in renewable clean energy sources is immense, enough to warrant calling it the Third Industrial Revolution. Particularly, as international discussions related to the climate change problem facing humanity intensify, the need for global cooperation to reduce carbon emissions is also growing. Among these, hydrogen energy, which can produce 2.75 times more energy than gasoline (122KJ per gram of hydrogen) and generates no greenhouse gases, is recognized as a clean energy source with immense potential as an alternative energy. Hydrogen energy can be utilized across various industrial sectors, particularly in transportation, where it is emerging as a key future power source. In materials engineering, diverse research on hydrogen production and storage is actively underway. The development of related technologies could lead to the creation of eco-friendly, renewable energy-powered vehicles, bringing immense public benefit to humanity.
Numerous leading automotive companies are currently racing to develop hydrogen vehicles for practical use. There are two main types: hydrogen engine vehicles, which use hydrogen directly as fuel in an internal combustion engine, and hydrogen fuel cell vehicles, which utilize fuel cells. Fuel cells generate electricity by reacting hydrogen with oxygen from the air. Hydrogen vehicles have been developed in various directions and have reached the stage of actual productization, with some already entering commercialization. They are therefore certain to become the driving force leading the hydrogen era. Furthermore, technological advances in the diverse applications of hydrogen as an energy source are not limited to hydrogen vehicles alone; they are expected to have a broad impact across the entire industrial sector.
Let us examine the technical elements to consider for the commercialization of hydrogen vehicles from a materials engineering perspective.
First, consider hydrogen engine vehicles. The fundamental technical challenge for hydrogen engine vehicles is backfiring under high load conditions. Backfiring, literally meaning the flame flowing backwards, occurs when the ignition timing is inconsistent during fuel combustion in an internal combustion engine or when the intake valve opening/closing timing is misaligned, causing the flame to reverse from the cylinder into the intake manifold. Therefore, hydrogen engine vehicles require both the establishment of backfire suppression technology and the development of high-power output technology. While hydrogen is a carbon-free fuel, its application in engines results in nitrogen oxide (NOx) emissions due to incomplete combustion. Unlike hydrogen fuel cells, the emission of nitrogen oxides is a major factor undermining the environmental friendliness of hydrogen engine vehicles. Reducing nitrogen oxides to non-polluting levels can be considered the most significant technical challenge for the practical application of hydrogen engine vehicles.
Furthermore, hydrogen fuel itself is expensive. Currently, most hydrogen is produced by separating it from fossil fuels, resulting in a higher production cost compared to conventional petroleum-based fuels. Hydrogen production via water electrolysis requires even more expensive electrical energy, so establishing technology to produce large quantities of hydrogen at low cost is essential. Currently, improving production process efficiency and developing alternative technologies to reduce hydrogen production costs are critical tasks.
Second is the hydrogen fuel cell vehicle. The core component of a hydrogen fuel cell vehicle is the stack, which is where fuel cells are stacked layer upon layer, analogous to the engine in a conventional vehicle. Various technical challenges exist in this area. Questions remain unresolved, such as whether performance holds up in cold winters, whether engine start-up vibrations are excessive, whether electricity supply is smooth, whether humidity within the stack is consistently maintained, and how to handle residual unreacted hydrogen after the reaction. Furthermore, since fuel cell manufacturers each propose different standards, guidelines for a unified, practical level of fuel cell are needed.
Furthermore, the most significant obstacle to the practical application of hydrogen fuel cell vehicles is the high cost of the stack, primarily due to the use of expensive precious metals as catalysts, which account for approximately 77% of the fuel cell system’s cost. While significant cost reductions have been achieved through advancements in catalyst technology and separator membrane technology that enhance fuel cell efficiency, the limited reserves of precious metals are absolutely insufficient even to partially replace current internal combustion engine vehicles with hydrogen fuel cell vehicles. Therefore, the development of low-cost catalysts that are stable at low temperatures and achieve high efficiency is essential for the practical implementation of hydrogen fuel cell vehicles. Research in this area holds the potential to bring significant changes to the global energy market, extending far beyond the automotive industry.
Extensive research is underway to utilize hydrogen energy, a clean, renewable energy source. Materials engineers are striving to solve numerous challenges: methods to produce hydrogen using electrolysis or water splitting instead of fossil fuels, ways to store this hydrogen, and techniques to regulate the amount of hydrogen generated. Ultimately, the core objective is to develop components like the internal combustion engine for hydrogen-powered vehicles and the fuel cell for hydrogen fuel cell vehicles. These technologies exemplify why materials engineering is essential for the automotive industry to address future environmental and energy challenges. If technical uncertainties are resolved soon, we will witness hydrogen vehicles—born from the splendid harmony of the automotive industry and materials engineering—running around us.
The successful commercialization of hydrogen energy will be a crucial turning point, contributing to environmental protection and sustainable development beyond simply providing a new form of transportation. Even at this very moment, laboratories are actively researching the efficiency, stability, and cost reduction of hydrogen fuel, which will play an essential role in solving humanity’s energy challenges.
