Al-jawab billahi at-taufeeq (the answer with Allah's guidance)
If a person performs Tarawih alone at home and could'nt pray it with Jama'ah due to reasons, he is allowed to and will not be sinful. (Aapke Masa'il Aur Unka Hal Vol. 3 Pg.67)
Also, making it a habit to leave a confirmed Sunnah (20 Rakats of Tarawih), will be reprehensible.
If you cannot pray Tarawih with Jama'ah, due to reasons then one is permitted to pray at home and recite Surahs (such as Suratul Fil etc,) as you normally do in other Salah.
However, one should be remorseful, because one is leaving a confirmed Sunnah of Rasulullah (Sallallahu Alaihi Wasallam) and his Sahabah (RA).
