Cerfacs participates in the Energy-oriented Centre of Excellence (EoCoE-III), starting in early 2024. The project applies cutting-edge exascale computational methods in its mission to accelerate the transition to the production, storage and management of clean, decarbonized energy. EoCoE-III is anchored in the High Performance Computing (HPC) community and targets research institutes and key commercial players who develop and enable energy-relevant numerical models to be run on exascale supercomputers, demonstrating their benefits for the net-zero energy transition. The project will draw on the experience of two successful previous projects EoCoE-I and -II, where a large set of diverse computer applications from four such energy domains achieved significant efficiency gains thanks to a multidisciplinary expertise in applied mathematics and supercomputing. EoCoE-III channels its efforts into 5 exascale lighthouse applications in the low-carbon sectors of Energy Materials, Water, Wind and Fusion. This multidisciplinary effort will harness innovations in computer science and mathematical algorithms within a tightly integrated co-design approach to overcome performance bottlenecks and to anticipate HPC hardware developments. A world-class consortium of 16 complementary partners forms a unique network of expertise in energy science, scientific computing and HPC, including 3 leading European supercomputing centres. In particular, Cerfacs will take part in the research on fast solvers needed in numerical simulations in the plasma core-edge interactions in ITER-scale tokamaks.