As Covid-19 spreads around the world, people have to make some change to avoid being infected. And due to the outbreak of COVID-19, the participants were not able to meet each other at the 5th International Conference on New Energy and Future Energy System (NEFES 2020) supposed to be held in Xi’an during July 14th-17th, 2020. Even though the conference was postponed to November 3rd-6th, some of the participants from other countries were still not able to visit China to attend NEFES2020 for COVID-19. So, the conference organizer located in Wuhan made a decision to hold it as an online conference (virtual conference without any physical participation and held by Microsoft Teams) during November 3rd-6th. Microsoft Teams Meeting provides a more effective way for us to hold an online conference via some function like sharing the presenters’ Power Point or video, discussing in the chat box or taking pictures. However, there were also some shortcomings about online conference regarding time differences and internet conditions. Therefore, it is a way to hold an international conference online.NEFES 2020 was sponsored by Harbin Institute of Technology, Weihai. It aims to provide a platform for researchers and practitioners in both industry and academia to share their latest achievements and discuss the possible challenges in terms of new energy and future energy system. This volume records the proceedings of NEFES 2020 and contains 85 rigorously selected manuscripts submitted to the online conference. All the manuscripts were selected depending on their quality and relevance to the conference.One hundred and nine participants including presenters and listeners from a broad geographical coverage of counties including China, Australia, Switzerland, Italy, Spain, Romania, Indonesia, Iraq, Poland, Japan, Mexico, India, Russia, Germany and Iran joined NEFES2020 and made it a successful conference. The conference program included welcomes speech, 3 keynote speeches, 25 invited presentations, 11 oral presentations and 16 poster presentations. About 5 minutes were left for each oral presentation, the audience could raise up their hands before the session chair allowed them to ask questions or left message in the chat box as well as wrote an email to the presenters. The conference program was outlined as follows:Welcome speech was delivered by Prof. Fuqiang Wang, School of New Energy, Harbin Institute of Technology (Weihai) of China for five minutes.Three keynote speeches were from Prof. Mattheos Santamouris, University of New South Wales, Australia; Prof. Hui Jin, Xi’an Jiaotong University, China; Dr. Eric Johnson, Editor-in-chief emeritus of Environmental Impact Assessment Review and Managing Director of Atlantic Consulting, Switzerland. Each keynote speech lasted for 40 minutes and delivered on November 4th.The other online presentations were delivered by researchers, scholars and experts such as Prof. Riyi Lin, Prof. Zehui Chang, Dr. Liqiang Zhang, Dr. Yushi Liu, Prof. Chongchong Qi, Dr. Diana Enescu, Dr. Luigi Costanzo, Dr. Claudia Masselli, Dr. Jan Kazak. Each oral presentation lasted for 15-25 minutes. The topics of the online presentations covered New energy resources, New energy device, smart grid load and energy management, optical technologies for smart grid, Solar cell materials and lithium-ion batteries.List of NEFES2020 Scientific Committee Members, General Chair, Chair of Technical Program Committee and Technical Program Committee are available in the pdf.