Long-Term Benefits of Network Boosters for Renewables Integration and Corrective Grid Security

TL;DR

This paper explores how using fast corrective actions with network boosters can significantly reduce costs and improve renewable energy integration in power systems with high renewable shares, compared to traditional preventive security strategies.

Contribution

It introduces a long-term analysis of corrective network security strategies with storage and flexibility assets, demonstrating substantial cost savings and operational benefits for renewable integration.

Findings

Up to 2.4 billion euros annual savings in renewable integration costs.

Corrective strategies enable better utilization of network capacity.

Long-term benefits are demonstrated through optimized investment models.

Abstract

The preventative strategies for $N-1$ network security dominant in European networks mean that network capacity is kept free in case a line fails. If instead fast corrective actions are used to overcome network overloading when single lines fail, this has the potential to free up network capacity that is otherwise underused in preventive $N-1$ security strategies. In this paper, we investigate the impact on renewable integration of a corrective network security strategy, whereby storage or other flexibility assets are used to correct overloading shortly after line outages. In this way, we find significant cost savings for the integration of renewable energy of up to 2.4 billion euros per year in an aggregated 50-bus model of the German power system utilizing these flexibility assets, so-called network boosters (NB). This offers a role for storage beyond energy arbitrage or ancillary services like frequency control. While previous literature has focused on the potential savings of NB in the short-term operation, we focus on the long-term benefits in systems with high shares of renewable energy sources, where the capacities and dispatch of generation and NB are optimised. We demonstrate the benefits of NB for various shares of renewable energy, NB and flexibility costs, as well as different allowed levels of temporary overloading the lines in both (i) a sequential model, where long-run generation investments are optimised separately from the NB capacities, and (ii) a simultaneous model, where generation is co-optimised with NB investment so that mixed preventive-corrective approaches are possible.