The outer part of the earth crust on which we live has been producing many kinds of natural resources and it maintains moderate temperatures on the earth by acting as a thermal storage with global scale. In order to save the energy consumption, it is necessary to develop new technologies for utilization of the underground environments. The authors have been developing underground facilities for utilization of the so-called cold energies obtained by strong ice or snow of winter season, and have found that these systems are very effective in performance. The thermal characteristics of the underground storage systems have been analyzed in this paper and are compared with those of some ground storage systems. A simple method has been proposed to predict the thermal performance of different types of thermal storage system. Finally a model, in which accumulation of snow on the ground was taken into account, was introduced to clarify the insulating effects of snow layer upon the total thermal performance of storage system.