ABSTRACT
'Nobody believed that integrating more than 5% variable renewable energy in an industrial country such as Germany was possible', Boris Schucht recalls. Yet, a persistent concern expressed about increasing the share of variable renewable energy in the generation portfolio relates to the anticipated negative impact these generators will have on grid stability. Stability in this context relates to the question whether system balance can be restored in the case of a major failure, or contingency event, in the absence of the inertial response provided by conventional power stations, such as coal, hydropower and nuclear. After a contingency event, which could arise, for example, in the form of the loss of a large power generator, the grid frequency will start to decrease immediately. In the power context, it is used to describe the amount of kinetic energy, measured in megawatt-seconds, that is stored in the rotating masses of all synchronously connected power generators.
