Clay tiles can often be confused with concrete tiles. The primary difference is clay tiles are much more brittle. Some companies may tell you that you can’t go solar or that they won’t do the install, but that is not the case.
Installing solar on a clay tile roof is often done with a comp-out, which where your installer will remove the tiles where you intend to put solar, then lay down composite shingle to install the array. After the array is installed, they would fill in the area around it with clay tile for a more aesthetically pleasing look.
Since clay tiles are so fragile, quite a few are likely to break during the installation. Don’t worry, your installer will replace all the broken tiles so your roof is still intact and looking good, but this does add to the cost of the project.