The electric power industry is in the midst of a critical period in its evolution. Nowadays, power grids are experiencing their greatest ever changes and challenges due the shift to smart and micro grids, renewable energy sources, new monitoring technologies, and the rapidly changing role of power networks. Existing high voltage transmission network is reliable and controllable but suffers from cascading failures and volatility. Its efficiency and use of resources are also poor. In addition to a considerable amount of electrical power wasting, approximately 20% of the generation capacity exists to meet peak demand 5% of the time. These issues become compounded with high penetration of renewable sources due to their intermittent behavior. The present proceedings includes the selected papers of the Fourth International Conference on Power and Energy Systems Engineering (CPESE 2017), which was held on September 25-29, 2017, in Berlin, Germany. The CPESE 2017 as a global academic event focused on Power and Energy Systems Engineering. The conference brought together the latest discoveries of researchers with the experiences of leading industry experts and engineers over the world.