No Partition to install Yosemite to I wanted to have a clean Yosemite installation.
Therefor I deleted the existing partition to make sure a completely clean installation is made.
The problem is that I cannot choose the partition to install to any more.
After accepting the license there is no partition to select from. Except for the recovery partition itself.
Macintosh HD is still there in the partition tool. but I cannot select it or rework it in any way because all options are greyed out.

Tried booting via recovery partition and stick.

How do I get back to having a partition to install to?
This post is for a different problem, but contains the same solution:

How do I fix my SSD after installing Yosemite and Enabling TRIM? No boot &amp; can&#39;t erase

I had to go to the terminal (it is available in the installation tool) and do as described in the link:

Use diskutil list
and check which volume/partition you want to delete (for me the clue was the size corresponding to my hard drive).

Then type diskutil eraseDisk JHFS+ name disk0.
"name " will be the name of the volume you create.

Close the terminal, go back to the installation tool and install as you would expect.