In today's global context, reducing CO2 emissions and mitigating environmental impacts has become an important issue, leading to the inclusion of smart cities among the top priorities of every country. This article aims to provide solutions for creating appropriate policies and overcoming obstacles in this field, with a focus on the importance of clean energy in the development of smart cities. Specifically, by focusing on three important sectors, namely Energy, Transportation, and Buildings, the aim is to help create efficient roadmaps for developing smart cities. To achieve this goal, successful policies and strategies implemented in successful cities will be examined to overcome the barriers in these sectors and achieve smart city status. The article emphasizes the importance of local government and stakeholder collaboration. This collaboration plays a critical role in creating appropriate policies for increasing the use of clean energy in different sectors, as the ideas of politicians and energy experts cannot be implemented without the support and participation of local governments. Therefore, the cooperation and support of local governments and stakeholders are of great importance for the development of smart cities. In short, the article emphasizes the importance of clean energy in the development of smart cities, provides recommendations for identifying appropriate policies and overcoming barriers, and highlights the critical role of local government and stakeholder collaboration. Therefore, this collaboration can be considered as a successful step towards the development of smart cities.