Energy related geomechanics include petroleum engineering and geothermal energy. Significant attention has been devoted since more than a decade to the behaviour of oil-well cements, to assess the integrity of cement-sheath in oil and geothermal wells. The microstructure and the thermo-poro-mechanical behaviour of the oil-well cement paste have been characterized through a multi-disciplinary approach. Problems related to the water injection in unconsolidated sand reservoirs and the permeability impairment during produced water re-injection are also investigated, based on advanced laboratory experiments at different scales. Advanced numerical analyses of the hydro-mechanical processes in fractured formations and fracture propagation during water injection are performed. Experiments and numerical models are also used to investigate the mechanical behaviour of gas hydrate-bearing sediments, so as to assess and minimize the environmental impacts of future exploitations of deep-sea methane hydrates.