This article provides a comprehensive analysis of energy efficiency and carbon awareness in emerging sixth generation of cellular networks (6G) open radio access network (O-RAN) systems. Guided by the proposed 6S lifecycle model (sense, shrink, sleep, shift, steer, and show), the article identifies key energy efficiency drivers such as artificial intelligence (AI)-enabled control, computational optimization, digital twin, and carbon- aware integration. A central contribution is the in-depth examination of metering methodologies and the standardization gaps stemming from O-RAN's disaggregated, virtualized design, along with a reassessment of its main energy consumption sources. This article also consolidates industrial and standardization efforts by presenting essential key performance indicators and measurement approaches for transparent, accurate, and trustworthy energy and carbon accounting.
Ak et al. (Thu,) studied this question.