This paper presents a novel power block concept for flexible electricity dispatch in a Concentrating Solar Power (CSP) plant. The power block is based on intercooled unfired regenerative closed air Brayton cycle that is connected to a pressurized solar air receiver. The Closed Brayton cycle uses a mass flow regulation system centered on the pressure regulation (auxiliary compressor and bleed valve) in order to control the Turbine Inlet Temperature (TIT). Doing so, the system is able to modulate turbine electricity production according to variations in the solar resource and changes in power electric demand. It has been found that the proposed power block is able to fully cover the electricity demand curve for those days with high solar resource. In case of integrating particles-based high temperature Thermal Energy Storage (TES) system, the power block can extend its production till the next day following the electricity curve demand during summer period. During winter period, the power plant can extend its production for a few hours due to the lower solar resource and the higher electric curve demand load. (C) 2019 The Authors. Published by Elsevier Ltd.