This is the 9th edition of the International Conference on Energy and Environment Research, ICEER 2022, took place in the middle of September, ISEP, Porto, Portugal (Hybrid). This book includes all the well-presented papers in ICEER 2022. The maturity of this conference series has now been reached, with a large number of participants from academia, as well as a few coming from the professional field. Linking together energy and environment research is not an easy task. However, it is now understood that these fields are interconnected and that the answer to the challenge of a sustainable future depends enormously on the willingness and capability of problem thinking in an integrated manner. This book presents the participants in ICEER 2022 contribution toward sustainability, through energy and environment research, thanks for all.