Massive PV integration will profoundly affect the power supply-demand dispatch scenario, such as the generator flexibility, dispatch of renewable production, and utilization of seasonal storage. This research presents a technical-economic assessments of a large-scale PV integration into grid with PHS balancing dispatch are presented, using real data of Kyushu, Japan. The impacts of PV integration on demand curves and detail storage dispatch scenarios are described, together with the simulation of economic performances of further PV integration considering the technical constraints, changes in power supply fraction and residual load duration curves are exhibited. PHS effectively absorbs the surplus PV production, maintains the grid flexibility, and further decreases the output from medium base plants. Due to technical limitations, simulation results indicate that around 50.0% of PV production will be curtailed when maximum PV generating capacity to peak load ratio reaches 1.02. As integrated PV capacity increases, effective PV integrations show significant variations across months over a year, and increases in PV annual penetration degrees become smaller with aid of PHS. Furthermore, in examining the promotion performances of PV integration with different PHS capacities reveals that PHS can effectively maintain low LCOE through recovering surplus production, especially at higher PV penetration levels. (C) 2018 Elsevier Ltd. All rights reserved.