Thermal energy storage systems are usually attached to solar power plants to extend their operation beyond sunshine periods. Solar heat collected during the day is divided between a power block and a properly-sized thermal energy storage system. The stored heat is later released to be processed by the power block during periods of little or no solar resource. An operating scheme for a dual-tank molten salt thermal energy storage system was developed. The scheme can be used to optimize charging and discharging processes of a thermal energy storage system to maximize power generation or revenue. (C) 2015 Elsevier Ltd. All rights reserved.