The paper investigates the possibility of ranking synchronous generators in a power system according to their contribution to system angular and voltage stability. The aim of this research is to establish fast semi-analytical methodology, i.e., avoiding transient simulations, to determine which synchronous generators can be safely disconnected from the network or replaced by other types of generators, e.g., wind generators, that do not provide similar support to the system. The ranking methodology proposed here is based on sensitivity analysis of system electromechanical modes and takes into account location of generators, their inertia, active and reactive power outputs and control functions provided by the generators. The results obtained so far are promising and largely agree with previously attempted methods to rank generators based on singular value decomposition and P-V curve analysis. Various operating conditions are examined and yielded the same ranking order across the different ranking methods at the respective operating points.