If they quoted you that much money, it sounds like there's a market there ready for disruption. 10k Euros is far too much, especially when you can do the job for many parking spots at once.

To be clear I was referring to shared parking with multiple spots. Where I live one underground parking is spanning multiple houses (I go from the parking directly inside), and there are maybe 3 or 4 in total. The provider would do the work "once and for all", considering everything from replacing the transformers for the additional power, to digging up the trenches and installing the upgraded cabling everywhere, and to every parking spot 11KW charger. The assumption behind this is that all the vehicles in the parking might end up charging at the same time (over night) so everything has to be sized for that.

The electricity provider normally sells the charger with installation for ~2500E. But that is assuming the end-to-end wiring already supports this. With dozens of chargers to install in the same parking the chances that the rest of the network was already so overspeced and up to the task are slim.

The manpower to dig a trench, replace cables and transformers is more or less the same whether you do do it for 10 parking spots or 100. So there's probably a sweet spot between having enough demand to split this between more people but not that much that you need the next level in transformers.

There may be substantial digging works to be done if you need to install new power lines to housing, which is not cheap, and various installation works are costly when done afterwards.

I live in Finland, where it is typical that blocks of flats as well as terraced and single-family houses have parking lots where there already is an electric supply to each car (for the purpose of heating the enging before winter morning starts). Even here it's not directly suitable for charging, because the feeding capacity is OK for warming cars, but not for quick charging. Fuse boxes and feeding cables have to be replaced, at a substantial cost.

People oppose power lines because they just don't want to have them near their house, or run through a forest where they walk.

Some people are afraid of adverse health effects of power lines (claiming cancer issues etc, which are fake news), but often it may also be just that powerlines are considered ugly, and seeing them from your window brings down your property value.

I thought we're talking about the underground power lines that go from a transformer to the house.

Later edit. Ok, that makes sense. For some reason I read it as "upgrading the residential grid to support the extra load of EV charging". There are already HV power distribution lines spanning the country. I understand building new transmission towers would be a NIMBY topic but is it a given that they can't be upgraded to expand the capacity over the same towers?

I was writing about the national power grid in Germany and other countries; basically, the lines at 220 kV or higher, or HVDC, that transfers power from e.g. the wind power stations at North Sea to the consumers and industry that needs electricity in Bavaria.

Likewise for Sweden: there is hydro and other capacity in north, but power grid cannot transfer enough power to users in Skåne (Malmö) so that industrial projects are cancelled.