Wednesday, November 30

Why your next car won’t be hydrogen (yet)


The electric cars they have become an object of desire, but they are also a way of showing off a certain virtue: a car that does not pollute or make noise. The problem is that, although the car is clean, the electricity it consumes is not.

Lithium is running out: what alternatives do we have for our batteries?

Know more

According to the World Energy Council, the average percentage of electricity generated from renewable sources worldwide was 15.3% in 2016. In the United States, it was only 10.1%, and in China the 5.7%.

The European Union on average produces 27.5% of its energy from renewable sourcesa percentage that in Spain is 46.68% in 2022 only behind Germany.

This means that, unless you recharge your car with solar panels, the energy that recharges the vast majority of current electric cars is not green. In addition, there is the problem of lithium batteries.

Although lithium is an abundant metal, the multiplication of demand in the coming years will cause shortages in the markets. In the middle of this mess, hydrogen as fuel appears as a solution for the future, but is it really?

Hydrogen and fuel cells

Those who know the history of blimp Hindenburg, you will know that hydrogen is a highly flammable gas, so the first idea would be to use it in an internal combustion engine, as if it were gasoline. However, there is a much better way: the fuel cell.

A hydrogen fuel cell It is a type of battery that produces electricity from a chemical reaction between hydrogen and oxygen in the air. With this electricity, the electric motor of the car can be moved. The only emission produced by operation is water vapour.

Hydrogen fuel cells are also more efficient than gasoline engines: a fuel cell converts the chemical energy of hydrogen into electrical energy with an efficiency of up to 60%. Gasoline engines have an efficiency of about 25%.

That is, hydrogen fuel cells are used as a means of energy storage, just like lithium batteries. In fact, hydrogen as a battery is much better than lithium because it has a higher energy density.

While a one kilo lithium battery can only store between 0.15 and 0.25 kWh of electricity, one kilogram of hydrogen contains 39.6 kWh. As much as it improves, battery technology won’t be able to catch up for a long time.

What is the problem? Obtaining hydrogen. Although it is the most abundant element in the universe, on Earth it is not available in isolation, but rather combined with oxygen in the form of H2O, water. And extracting hydrogen from water is complicated.

The chicken and the egg of hydrogen

Like electricity, most of the hydrogen that is produced for transportation is not green, that is, it is necessary to use fossil fuels to obtain it. For this reason it receives the name of gray hydrogen.

Hydrogen can be produced from natural gas, but the most common method is steam reforming methane. In this process, methane (CH4) reacts with steam (H2O) at high temperatures to produce hydrogen (H2) and carbon dioxide (CO2).

In other words, for each molecule of hydrogen, one of CO2 is produced, and this before adding the cost of reaching those high temperatures that the reaction requires, and that are achieved with fossil fuels. A process that hardly reduces emissions.

There is another way to get hydrogen: electrolysis. An electrolyzer is a device capable of separating water molecules into the oxygen and hydrogen atoms that compose them by applying electricity. The process emits oxygen as waste, which is stored for medical uses.

Hydrogen produced from electrolysis is cheaper than that generated from hydrocarbon sources because it does not require high temperatures or pressures to produce hydrogen.

However the hydrogen produced from electrolysis it is also less energy efficient than that produced from hydrocarbon sources, because electrolysis only produces a small amount of hydrogen.

Although electrolysis is a clean process, the electricity required may not be. Unless the electrolysis of hydrogen is produced with renewable energy, the hydrogen will remain gray and not green.

This change is already taking place around the world. In Fukushima, Japan, in the same place where the well-known nuclear disaster occurred, there are now an electrolyser powered by solar panels which can produce up to 100 kg of hydrogen per hour, 2.4 tons per day.

In Spain, it is planned that by 2030 electrifiers capable of generating 71.8 GW will be in operation, which will make it the main producer in Europe. The necessary electricity will be generated mainly by solar and wind installations. Does this mean that your next car will be hydrogen? Probably not.

Where are the hydrogens?

In addition to all the above challenges, the main problem with hydrogen is distribution. Pure hydrogen is very difficult to transport because it leaks out of the pipes. One solution would be to transport it mixed with natural gas using current pipelines. But it would still be to make it reach a distribution network of “hydrogenera” similar to that of current gas stations. A network that does not exist.

Currently there is only five hydrogen charging stations for vehicles in Spain, of which there are two –located in Barcelona and Madrid, respectively– that are for the exclusive use of buses. By comparison, there are more than 9,500 charging stations, not to mention that electric cars can also be recharged at home.

For these reasons, it is likely that hydrogen fuel cells will begin to be deployed first in freight transport, buses, trucks and container ships, before becoming available for private vehicles.

It will take even longer to be used on airplanes. But all of this will only make sense if hydrogen turns from gray to green as soon as possible.

If you don’t want to miss any of our articles, subscribe to our newsletters



www.eldiario.es