Energy production and consumption is always accompanied with environmental and societal issues. Electricity as onefinal energy form plays an important role in people’s activities. However, the electric utilities have focused on producingelectricity in abundance and with an affordable price. The production of electricity results in undesirable emissions and environmental effects called externalities. This paper assesses the externality cost of electricity production in Indonesia by using the life cycle inventory analysis approach. In 2025, the results show that the total external costs according to the government plan are 42 billion US$. In addition, low carbon society behavior will be introduced into the Indonesian society to reducethe externality cost in the long term Indonesian electricity expansion planning. The results of low carbon society actionsshow that in the long term the Indonesian electricity expansion planning of 34.6 TWh of electricity demand and 7.3 GW of installed capacity can be reduced from these actions. Finally, at the end of the period, these actions are successful, and reducing the total external cost by 2 billion US$.