Which one is better? Electric or hydrogen in mobility? – ENERTRAG.
With 20 kWh or 1 kg of hydrogen electricity, a car can travel 100 km. Self-generated electricity costs 5 ct/kWh, at the socket it is 30 ct/kWh. Hydrogen can be offered for 5 €/kg.
That’s the cost of 1 €/100 km with self-generated electricity, 6 €/100 km at the socket and 5 €/100 km with hydrogen. In view of such low costs, one wonders why there is even a discussion about “E or H2”.
And it’s an endless and passionate discussion: Which is better? Electric or hydrogen in mobility? The answer is as simple and Solomonic as it gets: both are needed, and the right measure must be found. The statement “the battery has won” is just as nonsensical as the claim “it only works with 100% hydrogen”.
This page here sets itself the task of questioning the many assumptions that are put forward as pros and cons.
First of all, according to what we know, there will be no purely electrical energy system – because we do not know any physical principle with the help of which electricity can be stored for a long time and inexpensively. The only known solution for storing large amounts of renewable electricity is hydrogen.
Electrolysis is the only known technology that can be used to tame the discontinuity of solar and wind energy, namely by converting the fluctuating part of electricity generation into hydrogen, storing it and using it in times of low energy supply. And how? In fuel cells, of course, because they have the highest efficiency, do not produce nitrogen oxide but only water.
But if the fuel cell is needed anyway, then one quickly asks oneself: Why install all fuel cells stationary? Wouldn’t it make more sense to install them in cars? Then they are better exploited and cars can always feed back into the power grids. this consideration shows what needs to be considered when it comes to E versus H2.
And most likely, the best solution is a vehicle that can drive 50 km purely electrically plus 500 km with hydrogen. And the driver will already think about which type of energy is the best for him at the moment: the cheap electricity from his own PV system in summer or grid electricity in winter – or H2 from the filling station if electricity is just too expensive or a long distance is pending.
Now to the rumors on this subject. The frequently encountered statements are black, the clarifications are blue.
There are only a few test facilitiesfor the production of hydrogen from green electricity. There are certainly not many plantsyet, but they produce many times the amount of hydrogen that is in demand in transport. Several plants have been in operation for 5-10 years. Not only ENERTRAG would like to expand its H2 generation capacities quickly – it only lacks the legal requirements.
Hydrogen is mainly obtained from fossil fuels by natural gas reforming. This is true, but the hydrogen obtained in this way is also used in the fossil fuel industry and has nothing to do with mobility. In Germany, much more hydrogen is produced from wind power than the existing fuel cell vehicles consume, and an expansion of capacities is possible very quickly.
Although efficiencies of 70 percent are now achieved in such plants, 30 percent of the primary energy alone is lost during generation. Of course, energy is also lost during hydrogen production. In the ENERTRAG plant, 120 sqm of H2 with an energy content of 3.2 kWh/sqm, i.e. 384 kWh, are generated with 500 kW.
And 384/500 gives an efficiency of 77%. It should be noted that with the increasing expansion of renewable generation, electrolysers in particular are needed in order to be able to use the electricity. Up to 30% would be lost due to curtailment, see below.
Hydrogen filling stations are too complex and too expensive and can only supply a few vehicles per day. This statement is also backward-looking and not fit for the future. Today’s filling stations are only built for the few existing vehicles, so they are relatively small and only built for 1-2 refueling operations per hour.
However, it is easily possible to build much larger filling stations that can refuel thousands of vehicles every day and which are then much cheaper per refueling process. By the way, anyone who drives a hydrogen vehicle knows how easy and trouble-free refueling is and that it really only takes 3 minutes.
Often the following calculation can also be found: 10 million vehicles that drive 150 billion kilometers a year, with a consumption of 1 kg H2 per 100 km, then need 1.5 million tons of hydrogen with an energy content of about 50 TWh, which requires over 60 TWh of electrolysis electricity.
This is also completely wrong – hydrogen cars will have a battery for an electric range of about 50 km. This will make it possible to drive up to 80% of the routes purely electrically. The fuel cell is only used for long distances and in times of electricity shortages. This also means that much less hydrogen is needed.
Hydrogen is the lightest of the elements and extremely volatile. The ion lattice of a steel vessel is hardly a barrier for the small hydrogen molecule. The first hydrogen test cars had the problem that after two weeks of downtime, almost all the hydrogen from the tanks had evaporated.
What sounds so logical is nothing more than linking correct statements by omitting their context into a false overall picture: the hydrogen that has evaporated in some test vehicles has by no means been lost due to diffusion through steel vessels, but because the vehicles were operated with liquid H2.
For its permanent cooling to -271 degrees Celsius, almost 1/10 of the tank content was consumed daily. The tanks of fuel cells with compressed gas vessels, on the other hand, are absolutely tight – even after months, no loss can be detected.
The hydrogen tanks are very complex and are made of carbon fiber reinforced plastic. A tank for five kilograms of hydrogen weighs 125 kilograms. Because the tank must not only be able to hold the hydrogen permanently, but also meet the safety requirements for cars.
In the event of an accident, it must not burst under any circumstances. That’s true – but these 125 kg also store 5 kg H2 with 33.3 kWh/kg, i.e. 166 kWh. An accumulator for a vehicle with the same range weighs 600 kg. Against this, 125 kg is almost nothing. In fact, fuel cell technology saves massively on vehicle weight.
The only supposed advantage of the fuel cell is the relatively short refueling times. But if you take a close look at today’s gas stations, this advantage is quickly gone. This is because the stored hydrogen must be compressed back to the 700 bar required for vehicles after each refuelling process.
This process takes time, so it cannot be seamlessly refueled one vehicle at a time. Today’s hydrogen filling station costs between one and two million euros and can store hydrogen for about 50 full refuelings, so it needs permanent replenishment, which causes further costs. If you compare gas station costs, you have to compare the same with the same.
A filling station with a capacity for 1,000 full refuelling operations per day at 5 kg H2 per day costs about 4 million euros (of which about half of the tanks cost at prices of about 15 €/kWh storage capacity).
This then makes about 1 € per refueling process from over 10 years. A filling station for 1,000 full refuelling with electricity of 75 kWh each costs € 15 million for the batteries alone at battery prices of 200 € / kWh when designed at 100%.
If you were to store only 25% of the daily charging power is still almost € 4 million – and the charging station could not supply electricity on several days of the year because there is not enough sun or wind. If you wanted to bridge these times, you would have to build large fuel cell power plants that then supply energy – here you can see that it is easier to install the fuel cells in the vehicles right away.
Electric vehicles can also serve the grid through load management by being able to absorb generation peaks. The idea seems obvious, but the batteries are already full after a short time. This only works with solar power, which is almost non-existent in this country in winter. Batteries are not able to postpone the abundant wind energy available in autumn to February – only electrolysis can do that.
And fuel cell vehicles can not only feed electricity back into the grid, but they can also refuel H2 at any time and thus bridge several weeks of dark doldrums. This would be impossible with electric vehicles, because they are then simply empty and could not be charged anywhere.
One kilogram of hydrogen currently costs 9.50 euros in Germany and is enough for about 100 kilometers. This means that hydrogen can currently – the real costs are likely to be higher – keep up with diesels or petrol engines, but is well above the operating costs for an electric vehiclethat, depending on the vehicle type, is content with 13 to 25 kilowatt hours per 100 kilometres and is therefore between 3.90 and 7.50 euros.
Hydrogen can be obtained from wind power for 5 ct/kWh. The electrolysis plant costs about the same as the wind turbine (still), which doubles the costs to 10 ct/kWh. In addition, there are about 5 ct/kWh for storage and transport. These together 15 ct/kWh correspond to 5 € per kg at 33.3 kWh/kg energy density of the hydrogen.
Today’s gas station price is only so high because there are hardly any customers. This means that 100 km with H2 costs 5 €, i.e. less than with electricity from today’s grid.
With self-generated electricity, costs of 1 to 2 euros per 100 km of purely electric driving can be achieved if the grid fees and all levies and levies on electricity are eliminated.
The fuel cell is very sensitive. Therefore, the air must be filtered very laboriously in order not to damage the fuel cell. Pure Stuttgart city air would immediately destroy a fuel cell. These expensive filters need to be replaced regularly. This is now very well mastered. Even after more than 70,000 km with the Mirai, we could not yet determine that costs for filter changes would have been incurred.
In addition, we can do much more meaningful things with hydrogen than driving around in the car with it. Hydrogen can add up to ten percent to natural gas or convert it into methane and heat via methanation – i.e. the reaction of hydrogen with carbon dioxide.
Methane is nothing more than natural gas and this can be stored in cavern storage facilities and in the gas network itself and, if necessary, converted back into electricity and heat in combined heat and gas-fired power plants or stationary fuel cells.
With hydrogen from electricity, we could reduce our import demand for gas from Russia or fracking gas from the USA. Again, this sounds so logical, but does not stand up to analysis. It is absolutely true that a large part of the H2 obtained from wind and sun goes into the natural gas networks and thus into heating and industry.
However, this does not contradict the fact that about 20% of hydrogen will go into mobility. However, methanation does not make sense because methane itself can only be used with high losses, see here. Only heat generation would be possible with low losses – but this can also be done with H2.
Hydrogen is explosive. That’s right. But gasoline and methane are also explosive. If gasoline runs out and ignites, there is usually no rescue. Outflowing methane is also extremely dangerous because it is difficult to evaporate even outdoors.
An outdoor hydrogen leak, on the other hand, is harmless, because before an ignitable mixture can be formed, the hydrogen has long since evaporated into the sky. In fact, the hazards of hydrogen are low compared to other fuels. And in buildings, H2 explosions can be easily prevented by permanently installing hot small glow points, which degrade escaping hydrogen through slight deflagration before an explosion occurs. Thanks for staying up to date with Hydrogen Central.
Even the incident in Norway in June 2019, in which a hydrogen filling station disassembled due to an assembly error, ultimately only showed that nothing happens to anyone. Mistakenly, the Airship Accident of the Hindenburg is often used as an argument for the dangerousness of H2. In fact, most of the people were able to save themselves, the ship could land on fire – which aircraft can do that?
READ the latest news shaping the hydrogen market at Hydrogen Central
E vs H2, December 15, 2021
