With the increasing penetration of renewable energy, the need for advanced flexible/scalable energy storage technologies with high round-trip efficiency (RTE) and high energy density has become critical. In this paper, a techno-economic model of a novel energy storage technology developed by the Oak Ridge National Laboratory (ORNL) is presented and used to estimate the technology’s capital cost. Ground-Level Integrated Diverse Energy Storage (GLIDES) is an energy storage technology with high efficiency which can store energy via input of electricity and heat and supply dispatchable electricity. GLIDES stores energy by compressing and expanding a gas using a liquid piston. GLIDES performance has been extensively studied analytically and experimentally. This study aims to develop a comprehensive combined performance and cost modeling environment. With the desired system storage capacity kilowattage, storage time (hours), and an initial RTE guess as inputs, the model optimizes the selection of system components to minimize the capital cost. The techno-economic model described in this paper can provide preliminary cost estimates and corresponding performance for various system sizes and storage times.