In the heating, ventilating and air conditioning (HVAC) industry, Cool Thermal Storage (CTS), commonly known as Thermal Energy Storage (TES), is the most preferred demand side management (DSM) technology for shifting cooling electrical demand from peak daytime periods to off peak night time periods. This paper shows how CTS offers a means of reducing the peak electrical demand in large Saudi office buildings. The effect of CTS based pre-cooled air as inlet to the turbine on enhancement of its efficiency is also discussed. CTS economics is considered, and a cost analysis is presented to illustrate the savings that can be achieved by the use of CTS in Saudi Arabia, especially for peak electric load levelling purposes during the summer period. It has been found that incorporation of a partial ice storage system in Saudi office buildings will reduce the peak time electrical power demand and the peak time cooling load in the range of 10-20% and 30-40%, respectively. Similarly, it is also estimated that in Saudi Arabia, the use of ice storage systems with gas turbines for inlet air cooling will increase the turbine's output by 30% and reduce its heat rate by 10% at a mere fraction of the cost of installing additional capacity for power generation in order to meet the summer peak demand.