We analyze the highest energy confinement in tokamak plasmas based on thermodynamic approach (plasma self-organization). The energy transport coefficients in the saturated confinement regimes are calculated from experiments in the T-10 tokamak. Using these coefficients, we estimate the maximal energy confinement for JET, ASDEX Upgrade, JT-60U, DIII-D and KSTAR tokamaks. Calculated energy confinement is in a good agreement with measured ones. Obtained results allow us to predict the maximal energy confinement in newly constructed machines up to a fusion reactor. The energy confinement for two basic scenarios for ITER is accessed.