The 9th ICCE takes place in Ottawa, Canada. Nestled on the banks of the majestic Ottawa, Rideau and Gatineau Rivers, Ottawa is one of the most beautiful G8 capitals in the world. Ottawa is also rich in culture and heritage with its many national institutions, parklands, waterways and historic architecture. This conference is organized to share and discuss recent developments in clean energy sector. The aim of ICCE2020/ICCE2021 is to gather researchers, scientists, engineers, practitioners, policy makers, from all over the world to present advances in the clean energy technologies. We are in an era in which there is a continuous progress in green energy sources and technologies and ICCE 2020 will provide a forum to exchange information, present new technologies and developments, and discuss the future direction, strategies and priorities in the field of clean energy.