2023-07-16 04:00:00
Posted at 12:00 a.m.
Currently, 99% of trains in North America run on diesel. If Canada is to meet its target of becoming carbon neutral by 2050, it is high time to consider alternatives.
To demonstrate that the answer lies in green hydrogen, the French multinational Alstom brought one of its trains from Germany to run on the Charlevoix rail network. Until September 30, its passengers travel using green hydrogen, a first in North America.
The beauty of this technology: it produces no carbon emissions, only water vapour.
A cable-free electric train
How is it possible ? We must first understand that a hydrogen train is an electric train. However, it is not directly connected to the Hydro-Québec network. No need either to connect the train to a terminal to recharge its batteries, like an electric car.
Instead, the electricity is generated through a hydrogen-powered fuel cell. Like a regular train, this train has a tank to fill, but this one is located on its roof, and contains hydrogen rather than diesel. With a single fill-up, the train obtains approximately 1000 km of autonomy.
PHOTO FROM WIKIPEDIA
Bruno G. Pollet, Director of the Canada Research Chair in Green Hydrogen Production and Professor at the University of Quebec at Trois-Rivières (UQTR)
This technology makes it possible to electrify the railway network without having to install power cables, also called catenaries. “It would be very expensive to build this infrastructure in Canada, because we have a huge territory to cover,” says Bruno G. Pollet, director of the Canada Research Chair in Green Hydrogen Production and professor at the University of Quebec at Trois-Rivières (UQTR).
This is one of the main reasons why North America lags so far behind in train electrification compared to the much smaller and densely populated continent of Europe.
The fuel cell
And now, how does the fuel cell generate electricity? In simple language, it transforms chemical energy into electrical energy.
This fuel cell, located on the roof of the train, combines oxygen from the air with hydrogen from the tank to create water molecules.
“This reaction releases electrons and this is what creates an electric current, explains Éric Rondeau, director of Alstom’s innovation center in America. We therefore obtain electricity and water vapour. »
PHOTO PROVIDED BY ALSTOM
The train’s fuel cell uses oxygen from the air and hydrogen from the tank to generate electricity and water vapour.
The term “fuel cell” can be confusing, because there is no combustion in the process. For those whose hydrogen is reminiscent of the Hindenburg zeppelin disaster, rest assured: the technology is completely safe, points out Éric Rondeau.
The molecule is very light and the tanks are on the roof, so if there were any leaks, the hydrogen would be dissipated into the atmosphere. We are not at all in risky conditions.
Éric Rondeau, director of Alstom’s innovation center in America
Where does hydrogen come from?
To produce green hydrogen, the reverse reaction is used: the electrolysis of water. By injecting an electric current into the water, the molecule can be separated into oxygen, which is released into the atmosphere, and hydrogen, which is stored in very high pressure reservoirs.
In the case of the Charlevoix train, production and supply are provided by Harnois Énergies. Since the company uses hydroelectricity, it is green hydrogen, meaning it does not emit any carbon emissions.
However, green hydrogen remains expensive, and the market is not yet developed in Quebec. “But it’s coming, that’s clear,” thinks Professor Bruno Pollet, who also sees green hydrogen as a way to decarbonize heavy industry such as cement works and aluminum smelters.
A good idea ?
This is not a magic bullet. Since we consume electricity to produce hydrogen, from which we generate electricity, there is necessarily a loss of efficiency. And for it to be “green”, it must use clean energy at the start.
PHOTO FROM THE UNIVERSITY OF SHERBROOKE WEBSITE
Mathieu Picard, professor in the mechanical engineering department at the Université de Sherbrooke
Hydrogen is not an energy source in itself. It should rather be seen as a battery.
Mathieu Picard, professor in the mechanical engineering department at the Université de Sherbrooke
Indeed, hydrogen makes it possible to store electricity, which is useful in transport to supply energy to a system without being connected to the network. But when compared to a battery, it is sometimes very advantageous… or not at all. It depends on how we use it.
Hydrogen is 10 to 20 times more energy dense than a battery, but half as efficient, explains Mathieu Picard. In other words, the hydrogen is lighter and stores more energy, but less is recovered compared to what was put in at the start. In both cases, there are trade-offs to be made.
The interest of hydrogen lies mainly in its lightness and its ability to cover longer distances without refueling. This is why it is considered to electrify heavy transport and the maritime industry.
For example, battery-powered freight trucks would never be profitable, believes Bruno Pollet. “The battery is about 50% of the weight of the load, so you couldn’t carry that much cargo. Also, it takes a long time to charge it. Hydrogen, which is light and whose tank fills up quickly, would be better suited.
But for personal cars, where battery weight is not a major issue, hydrogen is less desirable because its production consumes a lot of energy.
“We would like to have a single solution that solves all the problems, but this is not the case, nuance Mathieu Picard, from the University of Sherbrooke. There’s going to be a range of solutions, and green hydrogen is one of them. Especially when it comes to long distance heavy transport. »
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