Issues with internal roof insulation and later photovoltaic installation?

Hello

In an existing building from 1972, the roof is not insulated at all.
The concrete roof tiles also date from that time and, according to the expert, will last about another 5-7 years.
The rafters have a thickness of about 10 cm and a depth of 14 cm.
It is a gable roof with an east-west orientation.

I basically want to do two things with the roof:
1. insulate
2. install a photovoltaic system

If I have the roof insulated from the inside with blown-in insulation, it will cost me about 10,000 euros.

If the photovoltaic system is to be installed, I would also like to replace the roof tiles at the same time, since the scaffolding would only have to be set up once.

From an economic point of view, does it make sense to insulate the roof from the inside, or does it have to be dismantled or damaged during the installation of a photovoltaic system?
With blown-in insulation, the rafters are still freely accessible from the outside and are not covered by a vapor barrier.

Technically speaking, insulation is always better placed on the outside. In this case, energetically, a combination of insulation above the rafters and between the rafters (blown-in insulation / mineral wool, etc.) would of course be ideal, as 14 cm is not much nowadays. Additionally, the insulation above the rafters makes the roof nice and even for the new covering.

For every application, there are options to attach the photovoltaic system (rafter anchors). This can be explained to you in advance by the solar technician or the roofer. Regarding the roof tiles, I am currently leaning towards metal replacement tiles. Presumably technically better and overall cheaper than modifying tiles for the attachment of the rafter anchors for the photovoltaic system.

Suitable penetrations (e.g. 50mm) for photovoltaic cables are installed directly by the roofer and are usually sealed tightly! Roof vents can be replaced by flat vents and overbuilt with photovoltaics. If a satellite antenna is present, it should be relocated to the gable at the same time due to possible shading.