Teaching: He has taught a wide variety of courses for students and masters and PhD on energy resources, energy technologies, solar energy, design of energy systems, energy and climate change, sustainable development, as well as on energy issues and communication. 

Student supervision: He has so far supervised twenty three doctoral students and one hundred and fifteen masters students, from twenty countries in Asia and Europe. 

Publications: He has published sixty eight book chapters/monographs and more than ninety nine peer reviewed journal articles. He has presented seventy papers in conferences, seminars and workshops, and more than forty key note lectures. 
Scopus h-index: 32

Sponsored projects: Professor Kumar has extensive experience in carrying out research and research collaboration in South Asia (Afghanistan, Bangladesh, Bhutan, India, Nepal, and Sri Lanka), South East Asia (Cambodia, Indonesia, Laos PDR, Malaysia, Myanmar, Philippines, Thailand, and Vietnam), Central Asia (Kazakhstan, Uzbekistan, Moldova), China and Mongolia. His research has been in the areas of renewable energy resource assessment, solar thermal and photovoltaic technologies, energy efficiency in buildings and industries, Technology Needs Assessment for greenhouse gas mitigation, energy access, low carbon and smart cities, and low carbon energy systems and green growth. He has been involved as principal investigator in more than ninety five projects sponsored by development agencies, governments, private sector, UN agencies and non governmental organisations in research and development, equipment testing and capacity building programmes.

Outreach: He is the Editor of International Energy Journal (formerly Renewable Energy Reviews Journal), a quarterly publication. He served as Vice Chair of the Prosper.Net Board during 2016 – 2018. He was a Guest Professor at Tongji University, Shanghai, PR China.

Administration: He served as the Vice President for Academic Affairs at AIT during April 2013 – March 2019. He had also served as Dean of the School of Environment, Resources and Development at AIT during October 2005 – August 2009.

Education: Professor Kumar received his B. Eng (Honours) in Mechanical Engineering from Government College of Technology (Coimbatore), University of Madras, India; Master of Engineering (Energy Technology) from Asian Institute of Technology (AIT), Thailand; and Ph.D from Institut National Polytechnique de Toulouse, France.

Earlier, he was Reader at the School of Energy, Environment and Natural Resources, Madurai Kamaraj University, Madurai, India, and Program Research Fellow of the International Centre of Theoretical Physics (ICTP) at the University of Ancona, Ancona, Italy.

Research Areas: renewable energy resources and technologies, energy and sustainable development, and climate change mitigation.