A techno-economic-environmental comparison of residential solar energy systems employing an up-to-date market analysis

Journal article, 2025

To reduce primary energy consumption and emissions for households, this paper assesses the techno-economic-environmental performance of four residential energy systems based on a variety of solar technologies, i.e., solar photovoltaic (PV) panels, solar thermal evacuated tube collectors (ETCs), photovoltaic-thermal (PVT) collectors, and hybrid PV-ETCs, in comparison with grid-dependent systems. The primary innovative contribution of this study is the integration of realistic market-based cost models into the assessment framework, along with a comprehensive generalisation analysis to address the potential of solar-based systems across diverse contexts. An extensive market investigation on the current retail prices and quotations of components is first conducted, with up-to-date data integrated into the economic evaluation. The component sizes and operational control variables of the solar systems are optimised to achieve the minimum net present cost (NPC). A case study in Beijing shows that PV-, ETC-, PVT- and hybrid PV-ETC-based systems reduce the benchmark NPC of grid-dependent systems (USD 9890) by 34 %, 31 %, 44 % and 43 %, respectively, indicating that solar systems, especially cogeneration systems, are cost-effective in residential households. In contrast, ETC-based systems achieve the shortest payback period of 3.4 years and the highest internal rate of return at 42 %. Moreover, these solar systems reduce the benchmark carbon emissions of grid-dependent systems (9500 kg) by 35 %–74 %. The influence of local conditions and parameters on system performance is also investigated, showing that all solar systems can be profitable with annual solar irradiance of 900–2500 kWh/m² and electricity tariffs of 0.05–0.10 USD/kWh. A generalised analysis of load characteristics indicates that PV-, hybrid PV-ETC-, and PVT-based systems are optimal for householders with low domestic (<40 L/day), medium (40–200 L/day), and high hot water loads (>200 L/day), respectively. Finally, the economic feasibility of these systems is analysed in Beijing, Washington, London and New Delhi to span different global regions, revealing that all systems are profitable in these locations, and that hybrid PV-ETC-based systems in London achieve the highest NPC reduction of USD 20600.