Electricity grids for 100% renewable energy: Challenges and solutions

Abstract

On the way to a 100% renewable energy system electrical power grids face a number of new challenges: Big centralized power plants are being replaced by small distributed generators operating on renewable energy. Especially wind and photovoltaic power generation add new uncertainties to the generation of power. The distributed generation results in a different and even reverse power flow. On the other hand, the distributed generators also offer new possibilities like local power supply in case of emergencies. The local generation may even be beneficial for the reliability of the power supply. New types of electrical loads are emerging, like electric vehicles, heat pumps and battery storages. They may soon lead to local grid overloads. But fortunately, most of them are controllable loads. Thus, they can beneficially contribute to using the uncertainly generated renewable power. However, this requires a holistic view on the total energy system including a coupling of all involved energy sectors. Therefore, this chapter first gives an overview of existing publications about the impact on the electric power grid by the energy sectors and their inter-coupling. Then, a cellular power grid structure is proposed and described, which takes advantage of the distributed structure of renewable energy generation. Finally, some aspects on clustering and controlling such a cellular grid structure are presented.