Hydrogen should be the savior in the energy transition. What cannot be electrified directly or with sufficient comfort should be powered by hydrogen. Accordingly, the German federal government assigns hydrogen an important role in the decarbonization of the German economy. Our series of articles wants to take a closer look at the plans of the federal government and shed light on specific areas of application – especially in the automotive sector. Whatever is technically possible should also be checked for efficiency and scalability.
With a delay, the goal of one million registered electric vehicles in Germany could soon be achieved. Originally, this mark should have been cracked in 2020. Due to the rapid growth that is currently being observed in the sale of electric cars, the delay is now likely to be less than originally expected. However, in addition to the purely battery-electric cars, hybrid vehicles are also counted – and fuel cell cars, which are hardly noticed. But why do hydrogen vehicles currently have such a bad lobby? And how do they differ from battery-powered vehicles?
At least since the Paris climate summit COP21 it has been clear that there is no way around the exit from the fossil energy industry. This was made clear again by the ruling by the Federal Constitutional Court in Karlsruhe, which urged the federal government to adjust the climate targets at the end of April 2021. Before this change, the European automotive companies in particular had closed their eyes for a long time before they then – too late for many observers – opened up to electromobility. The current registration figures show that the traffic turnaround has now reached the public. With 50,000 registrations of electric cars per month, their number is growing much faster than that of charging stations.
Few fuel cell vehicles
However, the proportion of fuel cell cars is negligible. Only the two manufacturers Toyota and Hyundai currently each offer a “mass market” model, while the selection of purely battery-electric cars is increasing day by day. Their reach increases, sales prices gradually begin to fall – albeit only at a low level.
At the end of the 20th century, many representatives of the automotive industry assumed that numerous hydrogen cars would be driving through the area by the first few years of the new millennium. Today we know that these were wishful thinking, frivolously expressed, too positive prospects for the future. However, the H2-Technology exists and works, it has been manageable for a long time. Commercial fuel cell vehicles – both passenger cars and commercial vehicles – are on the road and offer advantages over battery-powered electric cars: They can be refueled quickly and they can cover a long range.
But there are also disadvantages: the scarce, extremely expensive infrastructure with hydrogen filling stations and the high costs. In addition, the discussion about the usefulness of hydrogen in individual transport is now more vehement than ever. While some rely entirely on battery vehicles, others propagate the H2-Car as a suitable successor for gasoline and diesel cars, although the overall environmental balance due to the energy-consuming H.2-Production is controversial.
Electric car vs. combustion engine
Most of the newly registered electric cars today are battery electric vehicles (BEV) and hybrid models. According to the Federal Motor Transport Authority (KBA), around 26,800 new electric cars were registered in May 2021. Compared to the same month last year, this corresponds to an increase of 380 percent. The market share was 11.6 percent. In addition, around 37,200 hybrid cars were added. The number of fuel cell electric vehicles (FCEV) is so far only marginal.
Basically, both variants are electric vehicles. An electric motor provides propulsion, unlike petrol, diesel and gas vehicles, which use internal combustion engines. While the energy is supplied to the combustion engines in the form of hydrocarbon compounds, which can be either liquid (gasoline, diesel) or gaseous (natural gas, liquefied gas), electric cars require electrical energy.
In conventional internal combustion engines, the chemical energy source reacts with oxygen (O2), which is 21 percent by volume in the air. During this oxidation, the CmHn compounds obtained from mineral oil are transformed, so that a wide variety of combustion products that are bad for the environment (CO, CO2, HC, NOx, Soot, etc.) and get out of the exhaust into the environment. In addition, the combustion engine emits water vapor, sometimes considerable noise and thermal energy.
Comparison with the electric car
It’s quite different with the electric motor: regardless of which type is used (synchronous or asynchronous motor), the electric motor does not emit anything except a little heat and makes less loud noises. The environmental balance directly on site is therefore much better than that of the combustion engine. However, the electricity must first be generated and stored, which must also be taken into account.
A battery vehicle has a comparatively large battery pack. Many accumulators are interconnected in order to be able to store as much electrical energy as possible. Depending on how the electricity was generated, the environmental balance of the electric car is therefore different. If the vehicle runs on green electricity, the operation is considered environmentally friendly. If the normal electricity mix is used, the emissions are of course higher. However, since a power plant, unlike gasoline or diesel engines in cars, almost always works in the range of the optimal load, the balance is even better than with an internal combustion engine, which is almost always used outside of its best efficiency. For the year 2020, the Federal Environment Agency (UBA) assumes 366 grams of CO in the German electricity mix2 per generated kilowatt hour. According to the UBA, it should have been 408 grams in 2019.
Battery as intermediate storage
It is a little more complicated with fuel cell cars, since hydrogen is used as an energy carrier. FCEVs also have a battery, but it is much smaller than the BEV and is primarily used as a buffer and for recuperation. The electric motor of a fuel cell car is also operated purely electrically, but the electricity can come from the battery and / or the fuel cell.