 Energy of the future 3
This chapter is about hydrogen. Although it doesn't solve the energy problem because it has nothing to do with direct energy generation, it plays an important role as an energy carrier. But there's been a bit of
hype. Our district, for example, relies heavily on hydrogen for bus propulsion.
Why do we call this a hype? Because hydrogen for buses, how else could it be, is based on renewably generated electrical energy, which is converted into hydrogen with some effort, transported to the filling
station, and then converted back into electricity on the bus.
Now you might ask why you don't fill the bus with energy directly from the power grid and then use it. With current technology, you would get twice the usable energy. For some reason, people believe, or have
believed, that the bus can't absorb this energy.
The issue is particularly controversial when it comes to city buses. It was simply not thought possible that these buses could now store up to 800 kWh, an amount they don't actually need in real-life operation.
If there is also an alternative with 500 kWh, most municipal bus companies are more likely to choose this one.
It has also been argued that hydrogen transported on the roof is lighter than batteries. Development seems to be overcoming this, too, as there are now even low-floor buses with batteries in the floor. In addition
to the significantly lower center of gravity, the walls also don't have to bear as much weight and can be made of composite materials.
Perhaps this topic makes sense for coaches. But the driver has to take a 45-minute break after 4.5 hours. Let's assume that a 100-passenger bus covers an impressive 350 km in 4.5 hours, consuming 450
kWh, and could recharge about 250 kWh today during the break, enough for the next 350 km.
The emphasis is on 'already today.' Megawatt chargers are in the pipeline, and then things look even more cost-effective. Then perhaps two drivers would make sense again, but at some point you have to let
the passengers out. And this also applies to long-distance trucks.
This suggests that hydrogen won't be needed for mobility on wheels any time soon. It seems indispensable for longer flights, but probably not in gaseous form, because it would also require at least half the
passenger compartment, but rather in liquid form.
Which brings us to the topic of 'imports,' because we already clarified in the first chapter that we cannot generate all the electricity we need ourselves in Germany. So what do we import? Ideally, hydrogen.
Why? Because its conversion will be cheaper in North Africa, for example.
So we import hydrogen as we need it: gaseous hydrogen and its further processing into liquids, for example, ammonia, methanol, or e-fuels. The latter are used by combustion engines that are still in
operation, but at extremely high prices.
But pure hydrogen could also be transported in gaseous form and used to power ships. Hydrogen even needs to be released from time to time, and could thus be used for propulsion when temperatures rise, for
example—a win-win situation.
A pipeline is probably not worthwhile because it usually requires continuous extraction of the same aggregate state. So, the newly constructed gas terminals aren't such a bad idea. Within Germany, long-
distance natural gas pipelines that have been tested for suitability could then be used.
The local natural gas grid is probably not fully compatible with natural gas. Gas heating will probably not survive, even if it's powered by hydrogen, and electricity for the house isn't that wasteful. Whether it will
always be a heat pump or partially radiate directly is still up for debate.
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