Collection of selected, peer reviewed papers from the 2015 9th International Power Engineering and Optimization Conference (PEOCO2015), March 18-19, 2015, Melaka, Malaysia. 
The 141 papers are grouped as follows: 
Chapter 1: Applications of Artificial Intelligence in Power Engineering; 
Chapter 2: Electrical Drives and Power Electronics; 
Chapter 3: Electrical Machines and Apparatus;
Chapter 4: Quality and Reliability of Power, Protection and Electromagnetic Compatibility in Power Systems; 
Chapter 5: Planning, Operation and Economics of Power Systems; 
Chapter 6: Energy Policy and Engineering Management of Renewable Energy Systems;
Chapter 7: Applied Decisions in Energy and Power Research