We use life cycle analysis, urban building energy simulations and urban form generation to compare the operational carbon emissions of buildings with building-integrated photovoltaics (BIPV) in locations with different grid electricity mixes in Southeast Asia. Our results show that BIPV installations can reduce operational carbon emissions of buildings by up to similar to 50%. The entire roofs and similar to 40-100% of the facades should be activated for solar energy harvesting, depending on the context and urban form. Additionally, we prove that it is more effective to install BIPV in countries with high carbon intensive grid electricity mixes, independent of climate and urban form.