Life cycle economic and environmental assessment for establishing the optimal implementation strategy of rooftop photovoltaic system in military facility

The Ministry of National Defense (South Korea) promotes its Defense Green Growth policy to reduce greenhouse gas emissions. Based on this background, this study aimed to conduct the life cycle economic and environmental assessment for establishing the optimal implementation strategy for rooftop photovoltaic system in military facility. Considering three factors (i.e., the orientation of the gable roof, the installation area of the PV system, and the slope of the installed panel), 12 implementation scenarios of PV system were established. The detailed results by prototype are summarized in terms of the two perspectives (i.e., the absolute and relative investment values): (i) Prototype 1 (south-north): P1-S/N (opt.) in terms of the NPV₂₅ (net present value at year 25) and P1-S (opt.) in terms of the SIR₂₅ (savings-to-investment ratio at year 25); (ii) Prototype 2 (southeast-northwest): P2-SE/NW (opt.) in terms of the NPV₂₅ and P2-SE (ext.) in terms of the SIR₂₅; and (iii) Prototype 3 (east-west): P3-E/W (ext.) in terms of the NPV₂₅ and P3-E (opt.) in terms of the SIR₂₅. The results of this study can help decision-makers to determine the optimal strategy for implementing rooftop PV systems on the gable roof of military facilities through life cycle economic and environmental assessment.