Hydrogen car: operation, problems, advantages

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, with the first commercially available models beginning to appear in 2014. Hydrogen cars offer many advantages over traditional gasoline vehicles, including lower emissions, greater durability, and longer range. However, there are also some significant challenges to overcome before these vehicles can become mainstream. In this article, we’ll take a closer look at how hydrogen cars work and explore the pros and cons of this emerging technology.

Hydrogen is not renewable, it must be produced

On Earth, hydrogen is not naturally available. Therefore, this gas cannot be considered a renewable source, at least in its primary form. Rather, it is a carrier of energy. Today it is produced by the gasification of coal and the chemical treatment of hydrocarbons, both unsustainable practices given the high amount of carbon dioxide released into the atmosphere (or by steam reforming of natural gas), a process that consists of reacting methane and steam water at a temperature between 700 and 1,100°C to produce synthesis gas, a mixture of carbon monoxide and hydrogen, or even through two environmentally friendly systems.

In the first case, algae, but also sludge and sewage, are used 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 fluid and produces oxygen and hydrogen in gaseous form. In the past, the electricity consumed for this operation was worth more than the hydrogen produced; therefore, the energy balance was negative and unsustainable. At least 45 kWh were needed to produce one kilogram of hydrogen, while 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 increasingly comes from renewable sources (mainly wind and solar) and that, in some countries like Germany, is linked to the need to absorb production peaks, to optimize the entire system and to make hydrogen a literally “renewable”.

A positive energy balance is possible

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

However, for hydrogen to be affordable and thus economically sustainable, further developments are needed. In the first place, the spread of refueling points and fleets of cars and buses capable of ensuring an adequate charge for each season. A mode of operation, in short, that minimizes financial risks and takes the distribution of this fuel from a niche technology to a massive solution.

A horizon in which some manufacturers firmly believe, attracted by the goal of producing vehicles with zero emissions (as long as the hydrogen is not derived, as has been said, from fossil fuels) and characterized by a generous autonomy, renewable in minutes.

A Mirai is filled with hydrogen

The hydrogen car is based 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 making it react with oxygen in a fuel cell. to produce electricity.

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

Fuel cells produce energy but also water

Fuel cells, at the heart of modern hydrogen cars, are electrochemical devices that allow electricity to be obtained 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, provide an electric current proportional to the speed of the chemical reaction, which can be used for any purpose. This reaction produces a waste product, water, which can be rejected in nature because it is perfectly compatible with the environment and is not altered at all.

Hydrogen must be compressed

The technical problems related to the use of hydrogen for the automobile are essentially related to its low energy density in volumetric terms (particularly compared to hydrocarbons) which requires particularly high pressures for storage or, alternatively, cryogenic treatment. Currently there is no alternative in the automotive sector, since both the adoption of large tanks and storage in the form of ammonia, metal hydrides, synthetic hydrocarbons (such as methanol) or nanotubes, both carbon and silicon, are unsuitable for use in compact vehicles. Storage pressure therefore plays a central role in the use of hydrogen for locomotion, although it opens the door to questions not so much of safety as of the suitability and durability of the system, since the compression of hydrogen entails energy expenditure .

The hydrogen car shares the advantages of electric cars

A hydrogen car is an electric car, but equipped with fuel cells instead of normal batteries. From a driving point of view, nothing changes, because advantages such as instantaneous thrust, linear flow, the absence of jerks when starting and first class comfort are not questioned.

BMW iX5 Hydrogen


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