Newly built single-family house - gas or air heat pump + photovoltaics + storage?

I can hardly imagine that, because hydrogen requires completely different and significantly higher-grade materials. Neither existing pipes nor pipe connections are suitable for hydrogen, and presumably not the heating system itself either.

Thanks for the info. Honestly, I was just repeating something I read on the internet (among others from a company that manufactures gas condensing boilers) and haven’t looked into it in detail yet. A lignite power plant near us is supposed to be converted to hydrogen, so I was probably a bit too optimistic. For example, I also hope for hydrogen cars. And for gas, I also rely on biogas and such. The prices for biogas are reasonable.

The problem with hydrogen is the underground efficiency. You can probably buy it at some point and put it in the heating system or the car. You just have to expect that heating and driving will then be at least five times more expensive than with electricity. You just have to want that. The next problem is the "sometime". By the time it gets there, we have to have been CO2-neutral for a long time. The problem with biogas is the endless land consumption and the destruction of the environment. We are already cultivating energy crops on 2% of our national area to generate about 1 percent of our final energy with it. The same area for wind and photovoltaics and we would be done with the energy transition. For this reason and due to the high costs and in turn poor efficiency, biogas production has been declining for some time.

We will talk to the two neighbors to find out whether they would (potentially) be disturbed by an air-water heat pump or not.

In my view, a good idea. Please keep us updated. I am particularly interested because we chose our property, among other things, based on the fact that there are no heat pumps installed in the neighborhood.

That's not really relevant. Either you keep the specified distances, or you don't. How the neighbor feels about it is legally irrelevant. I am also disturbed by all the cars on the street. Obviously, almost all of them comply with the valid regulations, which are obviously FAR too lax and far from the technically possible for new cars. Can I therefore have the street closed?

And with gas, I also rely on biogas and the like. The prices for biogas are reasonable

As already wrote, the resource expenditure for biogas plants is usually very unfavorable in practice, because maize is grown for these plants, which not only consumes land but also particularly depletes the soils.

The problem with hydrogen is the underground efficiency.

The problem is that we believe that exactly one technology will be able to do everything and that we find a serious disadvantage for each technology and focus on it instead of concentrating on specific application advantages. Hydrogen is an excellent energy storage with a sensational energy density. Storing energy in hydrogen is more lossy than in other storages. In use with fuel cells, hydrogen is extremely efficient. Methanol is also an excellent energy storage with a good energy density. As a liquid, methanol is easy to handle, production is making efficiency progress, and industrially produced CO2 can be reused for production. Methanol is suitable for powering efficient fuel cells. Current battery technology does not (yet) have the energy density to be used as long-term storage. With modern charging and discharging technology, they are extremely flexible with fast charging and good peak load capability. As powerful short-term storage, they are ideally suited—also in many (but not all) mobility applications with an electric motor. In the field of sector coupling, a number of other excellent energy storage options come into play. It is about the right energy carrier for the requirement and not about an all-encompassing leading technology. Do not let yourselves be guided by backward-looking skeptics; that guarantees leads to nothing. Better to take one or the other wrong path and make real progress that way.

Hydrogen is extremely efficient when used with fuel cells

Compared to the combustion engine, it could win. ;-)

No, of course hydrogen and methanol are something nice. And we will need both in huge quantities in the future. The only important thing is that the end consumer knows that it will not reach them. It all goes to industry. And even that will do everything possible to use as little of it as possible due to the exorbitant price.

Different picture: Many complain about wind power plants and electric cars and hope for hydrogen or e-fuels. You have to make it clear to them that driving with hydrogen/e-fuels means operating five times as many wind power plants as driving with a battery. And no – import does not work, it is much more expensive and not realistic at all, especially in 30 years.