Hydrogen is an important energy source that can substitute fossil fuels in future. It is unlimited, accounting for over 90% of the molecules existent in outer space and eco-friendly, producing only pure water in the process of generating energy by combining with oxygen. Actually, global efforts have already continued to move into a hydrogen society. Electricity generation systems and cooling and heating systems using hydrogen have already been commercialized across the globe, and hydrogen electric cars powered by hydrogen are also running on the road.
Hydrogen vehicles that have a wide potential in a hydrogen society vary from trains to vessels and drones, besides cars. Among them, hydrogen electric trams are gaining attention as an eco-friendly public transport for travel in complex cities. Here are characteristics of hydrogen trams that will be the backbone of a hydrogen society, as shown from Hyundai Rotem’s hydrogen electric tram under development.
Hydrogen that fuels hydrogen electric trams
Hydrogen electric trams move using electric energy generated by hydrogen fuel cell loaded inside the trams, unlike the general existing trams. Hydrogen fuel cells that produce electricity directly through electrochemical reaction between hydrogen and oxygen are the core technology of hydrogen vehicles.
The mechanism is that it splits hydrogen supplied to the hydrogen pole into a hydrogen ion and electron, sending the hydrogen ion to the oxygen pole through the electrolyte membrane and the electron to the oxygen pole through an external circuit. During the process, the electron produces electric energy, while the hydrogen ion meets an oxygen ion at the oxygen pole, producing water and heat. Simply put, it is an electricity generator that generates electric energy using hydrogen.
Hyundai Rotem’s hydrogen electric tram under development uses a hybrid method that combines a hydrogen fuel cell with a battery. The hydrogen fuel cell produces electricity using hydrogen supplied from a hydrogen tank and saves secondary power in an energy storage system (ESS), namely, the battery. The power saved in the battery is used when much energy is required such as starting the engine or speeding up, while the energy from the fuel cell is used for running at constant speed or speeding down. According to the concept car recently unveiled, Hyundai Rotem’s hydrogen electric tram can run at a speed of 70km for about 150km.
Zero carbon emissions, plus air purification effect
Trams, powered by electricity, are regarded as an eco-friendly transport that produces no carbon. Hydrogen electric trams, also powered by electric energy produced by fuel cell, do not produce carbon and even purify the surrounding air while running, which is different from the existing trams.
The fuel cell installed in the hydrogen electric trams collect outside oxygen to make electric energy. When the collected oxygen has impurities, it is purified through the filter and membrane humidifier for normal chemical reactions. Then, the used air is emitted as purified. Consequently, the trams can purify fine dusts or ultrafine dusts while simply running.
Air purification effect of hydrogen electric tram
Hyundai Rotem’s hydrogen electric tram can produce clean air at 107.6kg for an hour of operation, which 107 adults can use for an hour. 1,000 Hydrogen electric trams can purify fine dust emitted from 4,000 diesel cars while running. It is the same carbon reduction effect as 20,000 trees.
As above, hydrogen electric trams are the eco-friendliest transport that not just contributes to de-carbonization and reduction of green-house gas emissions, but also reduction of social expenses by reducing fine dust with air purification function.
Economic transport, hydrogen electric trams
Trains that move along the fixed tracks are economically feasible in operation. They require less energies than cars or airplanes. Basically, it is due to the train system designed to roll several carriages over metal rails. The driving condition of trains is a smaller frictional coefficient than cars (road-tire) and a smaller running resistance as many cars run at the same time. High-efficiency propulsion control using electricity energy is also an advantage. Trams are the result from applying the advantages of the railway system to general roads. In addition, they do not require electricity or power rails, which is more economic in building the initial infrastructure than other urban railway systems such as subway and light rail.
Hydrogen electric trams are more economic in infrastructure construction than general trams. This is because they produce power on their own, while wired trams receive electricity through the pantograph with facilities such as tram lines on the road. In particular, wire works are not easy in cities, which increases the utility of hydrogen electric trams.
ESS trams are also wireless as hydrogen electric trams and rather more economic in short-distance services. However, hydrogen electric trams that are light and use less energy are more appropriate for long-distance services as the consumption rate of vehicle is important. To minimize the economic feasibility, hydrogen electric trams may be operated in complement with ESS trams in a section where short-distance and long-distance services are both required.
Economic feasibility comparison between ESS trams and hydrogen electric trams
Mobility good for mega cities and convenient for the transportation vulnerable
One tram can carry people as many as three buses and 174 cars. Trams are good for carrying over 3,000 passengers an hour (up to 12,000 passengers) and tend to require less costs when the driving distance increases. In particular, as stated earlier, hydrogen electric trams that do not require wire works can be easily installed in complex cities. The introduction of hydrogen electric trams is expected to improve the mobility in cities, thereby solving the endemic problems of mega cities such as air pollution and traffic congestion.
Hydrogen electric trams run a fixed route at a fixed hour the same as the existing trams, reducing the uncertainty in travel time. Also, unlike metro, they are installed directly on the ground, which provides an increased convenience in transferring to other public transports in cities. In addition, Hyundai Rotem’s hydrogen electric tram is designed to have a low floor by modularizing all units from the fuel cell to the hydrogen tank and cooling system and housing them on the rooftop. The design is very convenient for people with mobility difficulties to board and unboard, as well as provide an extensive indoor space.
When will the hydrogen electric trams be commercialized?
Unlike in other countries, there is no city where trams are introduced yet in Korea. However, amid a growing national consensus on the need of eco-friendly mobility, many local governments are recently planning to introduce trams, including Seongnam, Busan, Daejeon, Incheon, Daegu, Ulsan, Suwon, Goyang, Changwon, Bucheon, Shiheung, Cheongju and Gumi, so it will be soon that we can see trams in our cities.
Hydrogen electric tram demonstration national research and development project
Actually, the Ministry of Trade, Industry and Energy is carrying out a “hydrogen electric tram demonstration national research and development project” for introduction of hydrogen electric trams. Hyundai Rotem, selected as the implementer of the project, together with the Metropolitan City of Ulsan last July 2021, undertook the development of hydrogen electric trams. For the project, Hyundai Rotem develops the fuel cell systems and main components of hydrogen electric trams for export, along with a test vehicle made with the said components and demonstrates and verifies the performance of the test vehicle, participated by Korea Automobile Research Center, Korea Railroad Research Institute, and Ulsan Techno Park.
Hyundai Rotem that has know-how on developing a test platform using its own element technologies and hydrogen fuel cells plans to develop the key components of hydrogen fuel cell jointly with the central and local governments, companies, research institutions through this demonstration project by 2023 and secure a new technology by verifying the performance and stability of the components. If the project goes successfully, early commercialization of hydrogen electric trams is possible.
The global demand for hydrogen electric trams is expected to increase by technical advances in hydrogen fuel cells and expanding tram market. Hyundai Rotem is predicted to become a game changer by obtaining a technical competitive edge against other train manufacturers through the project. Moreover, it plans to early introduce more eco-friendly hydrogen electric trams as part of continued efforts to reduce environmental contamination.
