Egypt is striving to improve energy exports and efficiency. Smart Buildings (SBs) promote sustainability and represents an essential pillar of smart cities. Smart Systems (SSs) are the physical infrastructure of SBs, serving the integration between their components and the users. Smart energy systems (SESs) are among the essential SSs in SBs. This article's aim is boosting sustainability, relying on increasing energy efficiency by harnessing the SESs, which divided into three key divisions: Smart energy management (SEMS), smart energy generating (SEGSs), and smart energy consumption (SECSs). It concluded the features of SESs to analyze several international and local case studies. Then, it developed and checked 35 initiatives of SESs, relying on in-depth local surveys, to address smartness features in energy systems (ESs) according to their priority, availability, and cost. These initiatives represent an appropriate and customized guide to architects, stakeholders, and decision-makers, especially in the Egyptian scope. The study results concluded that only 22 initiatives were achieved by 62.86% and addressed their efficiencies. The discussion interpreted losing the 16 absent and weak initiatives regarding the technical, economic, and social obstacles to strengthen the current Egyptian unprecedented urban development decision-making