Delivering negative emissions innovation on the right track: A patent analysis

Negative emission technologies (NETs) are becoming increasingly popular as an important means of combating climate change. However, NET development is still in its infancy compared with other solutions that have been thoroughly examined in the literature, such as renewable energies. Despite advances in the understanding of NETs, most existing studies are subject-constrained, case-driven, and literature-based, leaving a lack of comprehensive tracking of the wide range of NET options at a more granular level. The present study aims to fill this research gap from a patent standpoint by providing a thorough assessment of global technical improvements and achievements occurring in this domain over a 40-year timeline. After two rounds of rigorous screening of 936 patent families originally retrieved using a set of widely recognized patent search queries for NETs, our analysis kept 891 patents pertaining to 452 patent families. Then, the historical evolution and geographical distribution of these negative emission innovations were investigated, as well as tracked changes in technological hotspots, and innovation drivers and knowledge flows were identified. To advise on and steer the future direction of prospective NET breakthroughs, the study highlighted 16 subcategories of technologies within five NET categories.