Format: Slide Deck
Date: 27 November 2024

Power system stability

Ensuring system stability with a rising share of variable renewable energy

Olemedia | iStock

Preface
Key findings

Preface

The European Climate Law sets binding targets to achieve climate neutrality by 2050 and reduce greenhouse gas emissions by at least 55 percent by 2030. As shown in Agora’s 2023 study "Breaking Free from Fossil Gas", to meet these goals, Europe’s electricity sector must be largely decarbonised by 2040. This requires a shift from large, centralised power plants to distributed electricity generation based on wind and solar, and storage systems connected by inverters.

A topical question is how the integration of renewables will affect system stability and how to maintain it most efficiently. To address this, Agora Energiewende commissioned Moeller & Poeller Engineering to develop a detailed mapping of system stability needs, contributing technologies, and deployment strategies. Building on the technical analysis, we also carried out extensive exchange with system operators, authorities and industry representatives. Our aim is to make this complex issue more accessible to a broad range of stakeholders, initiate dialogue and support informed decision-making. All these elements are vital for maintaining stable power systems while keeping consumer prices affordable – and driving the clean energy transition forward.

Key findings

A successful transition to climate-neutral power generation requires a new approach to system stability.

System operation methods have traditionally been built around the physical properties of conventional power plants. Wind and solar power, and batteries are inverter-based technologies, connected by power electronics without intrinsic mechanical inertia. Aligning system stability management with renewables-based power systems should feature high on the agenda of policymakers and regulators.
To make informed decisions for a renewables-powered grid, it is important to clearly quantify system stability needs using transparent methods.

As renewable energy share increases, grid operators and regulators should carefully evaluate whether there are enough stability resources. Overestimating these needs can cause extra costs and delays in integrating more renewable energy, while underestimating them could threaten grid stability.
An optimal approach to system stability should focus on using the most cost-effective resources at the relevant location.

For example, while batteries, hydrogen and gas turbines can provide system services with few adjustments, it can be more technically complex for wind and solar, potentially leading to higher costs and delays. Such considerations should determine whether system operators install new technology or run system service auctions, or public authorities set technical provisions in tenders or enforce requirements through national and European network codes.
A comprehensive dialogue among system operators, manufacturers of generation and storage and relevant authorities is critical to identify the best solutions.

A shared understanding of terminology is essential to accurately identify and quantify system stability needs. The ongoing European network code revision is an important opportunity for such alignment. Converging towards harmonised EU-wide standards would further help make supply chains for clean technologies more efficient and thus support the transition to climate-neutral power systems.