Jonathan Cullen is a University Lecturer in Energy, Transport and Urban Infrastructure at the University of Cambridge and a Fellow of Fitzwilliam College.

Jonathan Cullen's research aims to characterise physical efficiency limits for energy devices and systems and provide a consistent framework for evaluating energy demand reduction options and emissions abatement strategies. This research makes use of in-depth analysis of energy systems and specialised integrative tools, while maintaining a broad awareness of the technical options to improve energy systems. Examining specific energy technologies within the context of the whole energy system will release the potential of technical innovation, provide new tools to evaluate the wider environmental consequences of energy technologies, and help to identify opportunities for future research