Hydrogen car: operation, problems, advantages

A hydrogen car is a type of car that uses fuel cells to power its engine. These cars have been in development for many years, and the first commercially available models began to appear in 2014. Hydrogen cars offer many advantages over traditional gasoline cars, including lower emissions, increased durability and greater autonomy. However, there are also some significant challenges to overcome before these vehicles can become mainstream. In this article, we will take a closer look at how hydrogen cars work and explore the pros and cons of this new technology.

Hydrogen is not renewable, it must be produced

On Earth, hydrogen is not available in natural form. This gas cannot therefore be considered a renewable source, at least in its primary form. It is rather an energy carrier. Today it is produced by gasification of coal and chemical treatment of hydrocarbons, both unsustainable methods, given the large amount of carbon dioxide released into the atmosphere (or by steam reforming of natural gas), a process consisting of reacting methane and water vapor at a temperature between 700 and 1,100°C to produce syngas, a mixture of carbon monoxide and hydrogen, or even, using two environmentally friendly systems, the environment.

In the first case, algae are used, but also sludge and waste water in special bioreactors. In the second, we rely on the electrolysis of water.

Wind or solar electrolysis is sustainable

During the electrolysis of water, a low-voltage current passes through the liquid, producing gaseous oxygen and hydrogen. In the past, the electricity consumed for this operation was worth more than the hydrogen produced; the energy balance was therefore negative and unsustainable. It took at least 45 kWh to produce one kilogram of hydrogen, whereas current technology, aided by the availability of aqueous solutions of renewable alcohols such as ethanol, glycerol and other biomass extracts, pegs the energy requirement at 18.5 kWh. The energy that is increasingly supplied by renewable sources (mainly wind and solar), and which in some countries such as Germany is associated with the need to absorb production peaks, to optimize the entire system and to make hydrogen a source that is literally “renewable”.

A positive energy balance is possible

The production of hydrogen from renewable sources enables a positive energy balance. This is the view of Toyota, for example, the first brand in the world to introduce a standard fuel cell car to the market, which is committed to creating a virtuous supply chain in Japanese cities. Yokohama and Kawasaki thanks to the Hama Wing high. -technological wind farm.

But in order for hydrogen to become affordable and thus economically sustainable, further development is needed. First, the proliferation of gas stations and fleets of cars and buses capable of ensuring an adequate load for each station. A mode of operation, in short, which minimizes the financial risks and takes the distribution of this fuel from a niche technology to a mass solution.

A horizon that some manufacturers are convinced, attracted by the goal of producing vehicles with zero emissions (provided that the hydrogen does not, as has been said, originate from fossil fuels) and characterized by a generous autonomy that can be renewed in a few minutes.

A Mirai is filled with hydrogen

The hydrogen car relies on electrochemistry

Hydrogen propulsion systems convert the chemical energy of this fuel into mechanical energy in two basic ways: by burning it in an internal combustion engine, as is the case with NASA rockets, the agency’s US spacecraft, or by reacting it with oxygen in a fuel cell to produce electricity .

Vehicles that follow the first strategy are called HICEV (Hydrogen Internal Combustion Engine Vehicle), while the second is called FCEV (Fuel Cell Electric Vehicle). The mobility of the future is definitely reserved for the latter, given the absence of emissions and the availability of the technology required to achieve remarkable mileage with a simple refueling.

Fuel cells produce energy, but also water

Fuel cells, which are at the heart of modern hydrogen cars, are electrochemical devices that make it possible to obtain electricity from the combination of hydrogen and oxygen without any thermal combustion process. The reaction required for this is based on the idea of ​​breaking down hydrogen molecules into positive ions and electrons; the latter, passing through an external circuit, provides an electric current proportional to the speed of the chemical reaction, which can be used for any purpose. This reaction produces a waste, water, which can be rejected in nature because it is perfectly compatible with the environment and does not change at all.

Hydrogen must be compressed

The technical problems associated with the use of hydrogen for cars are essentially related to its low energy density on a volumetric basis (especially compared to hydrocarbons), which requires either particularly high pressures for storage or, alternatively, cryogenic treatment. At present, there is no alternative in the automotive sector, as both the introduction of large tanks and storage in the form of ammonia, metal hydrides, synthetic hydrocarbons (such as methanol) or nanotubes, both carbon and silicon, are hardly suitable for use in compact vehicles. Storage pressure therefore plays a central role in the use of hydrogen for movement, although it opens the door to questions not so much about safety as the suitability and durability of the system, since the compression hydrogen implies an energy consumption.

The hydrogen car shares the advantages of electric cars

A hydrogen car is an electric car, but equipped with fuel cells instead of ordinary batteries. From a driving point of view, nothing changes, because the advantages such as immediate propulsion, linear flow, the absence of jerks when picking up and first-class comfort are not in doubt.

BMW iX5 Hydrogen

Leave a Comment