A CAES plant consists of three (3) major systems; the turbomachinery train, the underground air storage chamber and the balance of plant. The turbomachinery train and the underground air storage chamber interrelationship needs to be optimized with respect to performance and cost while the balance of plant supports this relationship and is dependent upon the site conditions. The qualitative relationship between the air storage chamber and the operation of the turbomachinery train have been reported in the literature. This paper takes a salt dome geology and examines the factors affecting optimization of a 100 MWe CAES plant design.