Smoothing effect for spatially distributed renewable resources and its impact on power grid robustness

TL;DR

This paper investigates how the spatial correlation of renewable energy outputs affects power grid robustness, revealing that higher correlation can significantly degrade grid stability and emphasizing the importance of considering correlation in stability assessments.

Contribution

The study introduces a new index for spatial correlation of renewable outputs and analyzes its impact on grid robustness using a realistic model and Japanese grid topology.

Findings

Spatial correlation varies with time scale, from weak to strong.

Higher spatial correlation degrades power grid robustness.

Considering correlation is crucial for accurate stability estimation.

Abstract

In this paper, we show that spatial correlation of renewable energy outputs greatly influences the robustness of power grids. First, we propose a new index for the spatial correlation among renewable energy outputs. We find that the spatial correlation of renewable energy outputs in a short time-scale is as weak as that caused by independent random variables and that in a long time-scale is as strong as that under perfect synchronization. Then, by employing the topology of the power grid in eastern Japan, we analyze the robustness of the power grid with spatial correlation of renewable energy outputs. The analysis is performed by using a realistic differential-algebraic equations model and the result shows that the spatial correlation of the energy resources strongly degrades the robustness of the power grid. Our result suggests that the spatial correlation of the renewable energy outputs should be taken into account when estimating the stability of power grids.