Geared turbines are used for small-scale power plants of up to approximately 40 MW. A speed reduction gear is installed between the generator and turbine, allowing the turbine to be designed smaller while operating at high speeds. Due to its small frame and high operating speed, geared turbines offer the following advantages over direct-coupled turbines; higher efficiency, smaller initial investment, easier maintenance, shorter delivery lead time, and smaller space requirements.
http://be-first.pl/ile-kosztuja-turbosprezarki-i-czym-roznia...

--------------------------------------------------
Note added at 4 hrs (2021-12-28 14:03:55 GMT)
--------------------------------------------------

cccccccccc
A geared architecture (48) for a gas turbine engine (20) comprising:
a fan shaft (76);
a frame which supports said fan shaft (76), said frame defines a frame transverse stiffness (KframeBEND);
a gear system (60) which drives said fan shaft (76);
a flexible support (78) which at least partially supports said gear system (60); and an input coupling (62) to said gear system (60),

https://patents.google.com/patent/EP2532858B1