Abstract In 2009, Energy Efficiency Design Index (EEDI) of ship was developed to reduce greenhouse gas emissions discharged from ship, and solar energy utilization on the ship can reduce fuel consumption and greenhouse gas emissions of ship. Considering different correlation parameters and energy conversion efficiencies of photovoltaic devices, availability factors of solar energy for new building ships were studied, and the effects of different latitudes, declination angles, hour angles and bevel angles were also analyzed in the paper. With solar energy employing as auxiliary power of ship at 39.1° of north latitude, its energy conservation and emissions reduction value were concluded with the proposed availability factors formula. Solar energy utilization on the ship is proved one pathway to meet the requirement of greenhouse gas emissions discharged from ship by International Maritime Organization (IMO).