A new international climate study has revealed that completely phasing out fossil fuels worldwide by 2050 would require global electricity generation to expand by 60 percent to 80 percent beyond levels projected in conventional 1.5°C climate pathways. The research also shows that a zero-fossil energy system could significantly reduce reliance on carbon capture and CO2 removal technologies while improving the chances of limiting global warming to 1.5°C after temporary overshoot.
The study was led by researchers from Kyoto University, Hokkaido University, and International Institute for Applied Systems Analysis (IIASA). It provides one of the first comprehensive multi-model assessments of what a fully “zero-fossil” global energy system would require.
The findings come as governments intensify efforts to implement the fossil fuel transition commitments agreed during COP28. International discussions are increasingly focused on how to accelerate the transition away from coal, oil, and natural gas while maintaining energy security and economic stability.
According to the study, conventional decarbonization pathways and complete fossil fuel phase-out pathways involve very different transformation strategies. Researchers used two globally recognized energy system models – the Asia-Pacific Integrated Model-Technology model (AIM-Technology) and MESSAGEix-GLOBIOM – to compare standard 1.5°C pathways with scenarios that fully eliminate coal, oil, and gas between 2050 and 2100.
The analysis found that achieving full fossil fuel phase-out by mid-century would require:
1.6 to 1.8 times more electricity generation by 2050
Much faster deployment of solar and wind power capacity
Rapid scaling of electrolysers and green hydrogen production
Significantly higher cumulative energy investments
Deep structural changes in industrial energy demand and consumption
Researchers said sectors that are difficult to electrify, including heavy industry and transport, would increasingly depend on hydrogen-based energy carriers such as green hydrogen, ammonia, and synthetic fuels.
The study highlighted that renewable electricity infrastructure would need to expand at an unprecedented pace. Compared with current investment trends, average annual investments in non-fossil electricity generation between 2026 and 2050 would need to rise by 2.5 to 3 times.
The researchers also identified major climate benefits from a complete fossil fuel phase-out. Eliminating fossil fuels substantially reduces residual CO2 emissions and lowers dependence on carbon capture and storage (CCS), bioenergy with carbon capture and storage (BECCS), and direct air carbon capture and storage (DACCS).
The study noted that earlier fossil fuel phase-out improves the probability of returning global temperatures to the Paris Agreement target of 1.5°C after temporary overshoot periods.
Shotaro Mori, Assistant Professor at Kyoto University and lead author of the study, said that full fossil fuel phase-out is technically achievable but demands much faster deployment of renewable electricity, hydrogen systems, and end-use transformation compared with conventional 1.5°C pathways.
Volker Krey, who leads the Integrated Assessment and Climate Change Research Group at IIASA, said the transition involves a profound restructuring of global energy systems, industrial processes, infrastructure investment, and international trade patterns rather than simply replacing one fuel source with another.
The study also examined the economic trade-offs between cost-optimal decarbonization pathways and more ambitious zero-fossil pathways. Researchers acknowledged that pathways allowing limited fossil fuel use with CCS may appear more cost-effective in the short term. However, they argued that full defossilisation provides a lower-risk long-term climate strategy by reducing dependence on uncertain carbon removal technologies.
The research further emphasized the importance of equity and just transition policies, especially for countries heavily dependent on fossil fuel production and exports. The authors called for stronger international cooperation, coordinated transition planning, and policy frameworks to support affected workers and regions.
The findings align closely with discussions under the Santa Marta Conference process and the Transitioning Away from Fossil Fuels initiative, both of which are exploring practical strategies for accelerating the global energy transition.
The study is expected to contribute to future climate negotiations, including implementation of COP28 and COP30 outcomes and upcoming assessments by the Intergovernmental Panel on Climate Change (IPCC).
BABURAJAN KIZHAKEDATH
