This paper presents an analysis of energy payback time and life-cycle conversion efficiency earning by solar energy park (SEP) at I.I.T Delhi, New Delhi, India. There are a number of hybrid photovoltaic thermal (PV/T) systems with stand-alone photovoltaic (SAPV) power supply in the SEP. The analysis is based on experimental and theoretical annual performance of each system. Life-cycle conversion efficiency analysis considering the embodied energy of various systems in the park has been performed for life cycles of 30, 40 and 50 years. It is found that the cost of power generated by the SAPV system decreases with increase in the life cycle of the system. The energy payback time of the park is 2.52 years and 17.21 years for thermal and electrical energies. The return on capital decreases marginally with increase in life cycle, however it increases marginally if embodied energy is taken into account. Copyright The Author 2009. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oxfordjournals.org, Oxford University Press.