The techno-economic performance of roof PV solar system depends on local climatic conditions. The energy conversion behavior of PV system will change as a result of the new solar irradiation data caused by climate change. This study aims to investigate the quantified impacts of climate change on the future performance of PV roof system with a general electricity load and legal maximum size of solar array. In this study, the morphing method is employed to predict the future hourly mean global solar irradiation data for the year 2030, 2050 and 2070. By using the current and future solar irradiation data as the inputs, a simulation model of PV system is built to simulate the long-term implementation of the systems in the capital cities of Australian states. The solutions of the model given by computer programme, includes the system's electricity generation, greenhouse gas emissions, and cost of energy are analysed, and all the solutions are compared between different climatic conditions of all the capital cities. It is shown that there is a nearly linear correlation between the increase of average external air temperature and the increase of solar irradiation from 2030 to 2070. For the PV system in the majority of cities, a 10 20% increase of economic costs between the 2030 and 2050 climate scenario would be required. It is also found that the Hoba system has the best techno-economic performance with the lowest economic costs and higher renewable fraction, at both current climate and future climate. (C) 2015 Elsevier Ltd. All rights reserved.