Flexibility in Power Systems of Integrating Variable Renewable Energy Sources

The intermittent nature of renewable energy sources brings a new kind of uncertainty to the functioning of power systems. In the last decade, the traditional structure of energy systems has entered a process of change due to the increasing share of renewable energy sources in the total installed power of countries. Concerns about this increase in uncertainty need to be addressed and the system needs to become more flexible. There is consensus, however, that flexibility comes at a price and that this price should be kept as low as possible without compromising dependability or the capacity to incorporate renewable energy sources. The investment and operational aspects of providing flexibility utilizing conventional generating sources, storage, and demand response are covered in this paper.