This work investigated different conceptual models for electric motorcycles, which are electric motorcycles with a home charging system, electric motorcycles using a battery swapping system, and electric motorcycles with battery swapping and photovoltaic systems, in four Southeast Asia countries. The current research focused on analyzing the impact of factors such as the number of battery packs in a swapping station, variation in battery swapping demand, the season, and photovoltaic panel size on energy utilization and carbon emissions associated with the entire energy supply chain. The objective of the current study was to evaluate and compare the well-to-wheel emissions using these different conceptual models, considering the varying energy mixes in four countries with a significant prevalence of motorcycle ownership, Thailand, Vietnam, Malaysia, and Indonesia. The results revealed that by using a 3 kW photovoltaic system, the dependency on grid energy can be significantly reduced and thus provide the highest benefits in terms of reduction of fossil fuel use and CO2 emissions. Although switching from internal combustion engine motorcycles to electric motorcycles could substantially reduce carbon emissions, it is only feasible when the primary resources used for generating electricity are sufficiently clean or battery swapping stations are equipped with a 3 kW photovoltaic system. In these four countries, electric motorcycles with battery swapping systems could accelerate the transition to a net-zero carbon emission society by reducing CO2 emissions by around 2.6-3.0 Mt-CO2 per year in the right environment. Prioritizing the decarbonization of power generation should be the primary focus, considering its critical role as a bottleneck within the system. The findings of this research hold significant value for decision-makers and investors who are actively pursuing smart city development and aiming to harness the potential of renewable energy sources.