This study proposes building driven-energy payback time (BD-EPBT) as a new life cycle assessment indicator. The BD-EPBT is the time required to outrun the total life cycle energy used in a power system-integrated building with annual surplus energy. As a result of a case study, it was shown that the BD-EPBT is highly associated with the embodied energy of construction materials. Also, by increasing the power system capacity (i.e., PV system) from 3 kW to 5 kW, BD-EPBT can be reduced by one fifth. The BD-EPBT is a novel concept capable of providing comprehensive analytics solutions to energy decision problems for building owners.
Keywords energy payback time (EPBT), life cycle assessment (LCA), life cycle energy (LCE), renewable energy resources, energy conservation in buildings, energy systems for power generation