Hydrogen - an alternative to the electric car?

Hydrogen vehicles are seen as a beacon of hope for climate-friendly transport. The most important questions and answers about fuel cells compared to batteries.

The majority of politicians, researchers and car manufacturers seem to agree: the future of road transport is electric. In order to achieve the climate targets, CO₂ emissions must be massively reduced, and this is only possible with vehicles that do not emit any greenhouse gases locally. But what about hydrogen cars? They appear again and again in the discussion when it comes to alternatives to the electric car. The opinions on hydrogen couldn't be more contradicting. Politicians like Transport Minister Andreas Scheuer have spoken out in favor of the technology, but many automobile manufacturers are not convinced - to put it in a friendly way. Volkswagen boss Herbert Diess called hydrogen cars a "pure waste of time", when CDU boss Armin Laschet broached the subject at a meeting, Tesla boss Elon Musk burst out laughing. But what actually is a hydrogen car? What are its advantages and disadvantages? And how environmentally friendly are they really?

How does a car run on hydrogen?

The reason why the drive is repeatedly used as an alternative to electric cars is the short refueling times and the carbon footprint.

 

Because actually hydrogen vehicles are also electric vehicles. The fundamental difference lies in the type of energy storage. In the case of electric cars, it is the battery; in the case of hydrogen vehicles, it is a special tank in which the hydrogen is transported. With the help of a fuel cell, hydrogen and oxygen react to form water, producing heat and electricity, the latter driving the car. That means: a fuel cell car produces its own electricity.

Is the production of hydrogen climate neutral?

Most of the hydrogen is currently still produced from natural gas. Ten tons of CO₂ are produced as a by-product for every tonne recovered.

 

This gray hydrogen increases the greenhouse effect. This only works in a climate-neutral way if the resulting CO₂ is stored (blue hydrogen). On the other hand, only green hydrogen is really sustainable. It is generated from renewable energies by electrolysis. Electricity from wind turbines and solar collectors is then used to split water into hydrogen and oxygen. Worldwide, the share of this climate-neutral variant is currently only two percent. Turquoise hydrogen is also currently a niche. Solid carbon remains as a by-product that can be reused.

What is the advantage over diesel, gasoline and electric cars?

Operating a car with hydrogen is locally climate-neutral under these green production conditions. In other words, in contrast to petrol and diesel, there are no greenhouse gases that are harmful to the environment when driving. This is what the hydrogen vehicle has in common with conventional electric cars. Only a little water vapor comes out of the exhaust of a fuel cell vehicle.

What are the downsides?

On the other hand, there is the enormous energy consumption that arises before the hydrogen gets to the car. In addition to production, transport is also complex. Hydrogen is either cooled to minus 253 degrees Celsius until it condenses into a liquid or compressed as a gas. A pressure of around 700 bar is required for this in car tanks. (1 bar = 0.986923 atm)

How is the overall efficiency compared to a battery car?

The key is the production chain of the energy source: In the case of an electric car, the electricity from the power station or wind turbine ends up directly in the battery and on the road via a charging station. So around 70 percent of one kilowatt hour of electricity arrives at the mechanical parts. In fuel cell cars, the electricity takes a detour via the artificially produced hydrogen. In the end, the efficiency is only 28 percent. That is marginally better than the gasoline engine, which comes to around 26 percent. This means that almost three quarters of the electricity used cannot be used to drive the fuel cell car; so it needs two to three times as much electricity per kilometer than an electric car.

 

How many gas stations are there?

In addition, there is currently no nationwide supply of hydrogen in Germany. According to ADAC, there are only about 100 filling stations that offer the fuel. By way of comparison: diesel and petrol are available in 14,000 locations, there are around 40,000 public charging points. In neighboring countries, the situation is even worse. Austria and Switzerland each have five hydrogen filling stations. That makes a longer vacation trip almost impossible.

What does a kilogram of hydrogen cost?

 

The fuel costs of a fuel cell car are about the same as petrol and diesel. One kilogram of hydrogen costs 9.50 euros. A car can travel 100 kilometers with it.

 

Who is currently building fuel cell vehicles?

For most automakers, hydrogen is a niche business. There are currently only two vehicles on the market - and they are expensive. Hyundai builds the Nexo, a mid-range SUV with an upper-range price. This fuel cell car costs at least 77 290 euros. Toyota describes its Mirai sedan as an "elegant entry-level model". At the price of 63,900 euros. This year, BMW presented the iX5 Hydrogen at the IAA, which is to be sold in a small series at the end of next year. Mercedes-Benz has now discontinued the GLC F-Cell, Honda only offers the Clarity Fuel Cell in Japan and California.

How safe are the cars?

Many people still know it from their chemistry class: Hydrogen burns in the air with a weak blue flame. Since it is lighter than air, it evaporates quickly. To compare the risk of fire with a car with a petrol tank, researchers from the University of Miami drilled a small hole in the fuel lines of a combustion engine and a hydrogen car in 2003. Both vehicles caught fire, the gasoline engine was already on fire after a minute. The hydrogen vehicle remained largely intact because the hydrogen escaped upwards and went up in a jet flame. The European Parliament set safety standards in 2009, including a particularly stable tank. However, its production is complex and consumes a lot of energy.

What is the potential of hydrogen?

In a direct comparison with pure battery cars, fuel cell vehicles perform poorly. In addition, Germany is still a long way from a green power supply. Nevertheless, hydrogen is an important energy carrier of the future. It is justified wherever pure electromobility reaches its limits - in shipping or as a drive for planes and trains. Drivetrains are also being researched in trucks. Road freight traffic accounts for a quarter of all traffic emissions in Germany. Almost all major manufacturers are working on the technology, but only a few trucks and buses from Hyundai and Toyota are ready for series production. However, 62 companies, including Daimler, Iveco, Shell, Michelin and Total, have agreed to put 100,000 hydrogen trucks on the road across Europe by 2030."