After having dealt in part 1 of our brief series with what German car manufacturers have to offer or are planning in the field of electric cars, be it battery or hydrogen, in part 2 we take a closer look at the batteries or fuel cells and their ranges and address the topic of environmental friendliness.
HERE is part 1 of the series Mobility of the Future – Battery or hydrogen or both?
Battery
The range of a battery is primarily determined by the charge capacity or rather its management system. Tesla is still the undisputed leader in this field, thanks to its sophisticated management system. The Model S can travel up to 600 kilometers using the appropriate battery without recharging. However, this version using the 100 kWh battery also costs an impressive 86,800 euros. A BMW i3s, on the other hand, can only travel around 340 kilometers with a 42.2 kWh battery charge. However, with its basic equipment it also costs less than half as much as the Tesla: 41,600 euros. A car with a fuel cell, on the other hand, has a range of about 500 km, the new Toyota FCHV-adv is supposed to reach 800 km 0n one tank of fuel.
At present, lithium-ion batteries are used almost exclusively in electric cars as they have a high energy density and can be charged frequently without significantly reducing their capacity. Tesla is again the front-runner here. Elon Musk’s company designs the engines to cover a range of around 1,6 million kilometers. A battery in the Model 3 usually lasts up to 800,000 kilometers. German manufacturers reckon on a battery life of 100,000 to 200,000 kilometers.
In order to manufacture the batteries, however, numerous raw materials such as lithium, cobalt, nickel, manganese and graphite are needed, which have to be imported almost entirely from overseas. Since most of these raw materials are not infinitely available, they are expensive, which is also reflected in the price of the batteries. The battery for a small or medium-sized car costs an average of 10,000 euros, and costs 20,000 euros for a Tesla.
CO2 Balance
And now the question arises as to whether a zero-emission car really is actually no longer a burden on the environment. The answer is simple: there is no such thing as a zero-emission car, as plenty of CO2 is released when the raw materials are extracted. The Swedish Ministry for the Environment has discovered in a study that between 150 and 200 kilos of CO2 are produced per kilowatt of storage capacity per battery.
Apart from that, the electricity needed to charge the batteries first has to be generated, which in Germany is anything but emission-free. The German “energy mix’ still draws most of its energy from coal-fired power plants, which means that a ‘locally emission-free’ electric car powered by a rechargeable battery is now polluted with 87.0 g/km CO2, according to a Daimler study.
Things seems to be a little better in countries like France, where electricity also comes from a mix, but mainly from nuclear power plants. It remains to be seen what the final environmental balance will look like in that case, when one takes into account the problem of safely storing burnt-out rods.
The best CO2 balance would of course be if the electricity came purely from renewable resources. Like in Costa Rica. Believe it or not, the small Central American country obtains more than 98 percent of its total electricity requirements from renewable resources. The largest part of the electricity (78 percent) is generated from hydropower, here around ten percent is generated using wind and geothermal energy, while solar and bio-energy account for a negligible proportion of just under one percent.
And just as battery electric cars have turned out to be less emission-free than they may seem, electric cars with a hydrogen tank are also in some ways inefficient due to how they generate electricity.
Hydrogen fuel cells
While the extraction of raw materials and the production of rechargeable batteries lead to a lot of pollutants being released into the environment, a car with a hydrogen fuel cell would only burn hydrogen, which is absolutely harmless to the climate and more environmentally friendly than a battery car. This is the argument put forward by the proponents of the hydrogen engine.
In a hydrogen fuel cell, a chemical reaction between hydrogen and oxygen produces electricity, which then passes through to the engine. This chemical reaction produces no pollutants and the car simply releases water vapor into the environment. As a result, the hydrogen fuel cell car, like the battery car, is “locally emission-free”. There is only one small problem: you first need electricity in order to produce hydrogen.
Hydrogen is not a natural element, it cannot simply be extracted and must therefore be produced. This production takes place by a so-called “electrolysis”. Atoms of water (H2O) are split into hydrogen (H2) and oxygen (O) using a large amount of electrical current. Only then can electricity be generated anew in the hydrogen fuel cell, once the oxygen in the air turns the hydrogen back into water and converts the energy stored in the hydrogen into electricity.
Due to the coal-heavy energy mix in Germany, hydrogen cars would have a much worse CO2 balance than battery powered cars. Moreover, according to figures from the Transport & Environment agency, the battery-powered car converts 73 percent of the electricity originally generated into propulsion, whereas the fuel cell car converts only 22 percent. More energy is used during the transport of hydrogen as well as petrol and diesel to the fuel stations for cooling and compression. First during production and then for storage at the fuel stations. All in all, according to the latest figures, ten times as much energy is required for operating a hydrogen car as for a battery-powered car. This means that 870 grams of CO2 would have to be counted for every 100 kilometers driven.
Although It should be noted that these calculations are nevertheless based on values from the German energy mix and would look completely different for electricity from renewable sources.
Energy generation from exhaust, brakes and solar cells
So why not charge the battery while driving? Since the introduction of hybrid engines in 2014, Formula 1 has used a technology that does just that. The MGU-H (Motor Generator United – Heat) is an engine which is connected to the turbocharger and converts energy from exhaust fumes into electrical energy. The MGU-K (Motor Generator United – Kinetic) converts heat that is generated during braking and releases that heat again during acceleration.
In a regular car on the road, it is possible to recover kinetic energy generated by the motion of the wheel suspension. Or you do it like Toyota does in the Prius PHV, and equip the body of the vehicle with solar cells that extend the range. All good ways to further improve the CO2 balance of the “locally emission-free” car.
More articles on electromobility and batteries HERE
More articles on electromobility and fuel cells HERE
