In contrast to the conventional monofacial photovoltaic (PV) modules, bifacial PV modules yield more electrical energy by utilizing the reflected or scattered light from the ground and surroundings. The energy generation efficiency of bifacial modules is determined by both the front-side and the rear-side output power. In this study, we compared the IV parameters as well as field performance of different module structures to further realize the influencing factors dominating the energy gain of bifacial modules. Our results show that the glass/glass bifacial modules encapsulated with bifacial solar cells provide over 6% more energy yield compared to the glass/ backsheet monofacial modules encapsulated with regular monofacial solar cells. Due to optical enhanced effects of a reflective coating on the rear glass, the energy yield gain of bifacial modules can be increased to above 10%, even though the bifaciality factors were reduced from 72% to 64%. Our study indicates that enhancing the front side output power of bifacial modules produces more benefits.