Abstract：An energy trilemma addresses three often conflicting challenges:energy security,equitable access to energy,and environmental sustainability.Maintaining this balance in the context of rapid transitions to decentralized,decarbonized,and the digital system is challenging with the risk of trading off equally essential goals.This study examines the energy trilemma and the transition to sustainable energy in the top ten CO₂-emitting countries in the world,using fixed asset investment and energy use as moderators from 1990 to 2016. The top ten CO₂-emittingcountries are China, the United States, India, Russia, Japan, Iran, Germany, South Korea, Saudi Arabia, and Indonesia. For the empirical analysis, we applyadvanced econometric techniques.We found a trilemma in the world energy sector,and the transition to sustainable energy simultaneously enhances economic growth and environmental quality in the long-run. Energy trilemma,sustainable  energy transition,investment in fixed assets,and energy use all contribute to econo-mic growth.The energy trilemma is negatively correlated with environmental quality. Fixed asset investments and energy use are positively linked with enviro-nmental quality. In addition to enhancing economic growth, investments in fixed assets and energy use harm the environment. Policymakers in the top ten CO₂- emitting nations should improve and integrate their energy policy actions to promote energy security, environmental strategies, mobilize investments that encourage technological innovation, facilitate clean energy transition that maximizes social and economic benefits that support environmental sustainability.

Keywords：Economic growth; Environmental quality; Top ten CO₂-Emitting countries in the world; Transition towards sustainable energy; Trilemma of world energy