Flexibility (Power System)

Flexibility: Concept Definition

According to the International Energy Agency, the flexibility of a power system refers to "the extent to which a power system can modify electricity production or consumption in response to variability, expected or otherwise". Another source described it as "the modification of generation injection and/or consumption patterns in reaction to an external signal (price signal or activation) in order to provide a service within the energy system" .

Flexibility: Why It Matters

Load balancing is not the only service a power system must perform flexibilty. There are many other services the operators of a power system must consider to make the grid stable. The three main services for the reliability of a power system are: load balancing, frequency response, and voltage response.

Renewable sources, together with some battery storage, can already perform some of these services better than a conventional power system. For example, renewable sources can supply reactive power (and therefore voltage response) even when they are not giving real power, and batteries can perform frequency response better than conventional sources. Currently a renewable power source integrated with a battery storage system is already cost competitive to some conventional sources, and such implementation will boost the reliability of the grid.

However, current capacity of dispatchable renewables or batteriers is not enough to cover variations of the residual load curve. So the residaul load flexibility of a power system must still be performed mainly by conventional dispatchable sources, with the aid of some demand response.