Non-Firm Grid Connections: A Review of Access Types, Mechanisms, and Regulatory Frameworks

M. Romeo Monterde, E. F. Álvarez, M. Valarezo

Current Sustainable/Renewable Energy Reports Vol. 12, nº. 1, pp. 23

Summary:

Purpose of Review

Non-firm (flexible) grid connection agreements are emerging as a fast, lower-cost alternative to traditional firm access for integrating renewable and distributed energy resources (DERs). This review examines: Which types of non-firm agreements exist, how are they implemented, and what lessons can be drawn from recent regulatory pilots?

Recent Findings

Literature and pilot projects reveal four predominant models of non-firm grid connections: capacity-limited, time-limited, dynamic operating envelopes, and fully flexible based access. These models are being formalised through legislation or regulatory guidance in the United Kingdom, Australia, Spain, and in various countries of the European Union. Their implementation is increasingly supported by digital monitoring and growing links to local flexibility markets.

Summary

Flexible connections can reduce connection costs by up to 80% and halve leadtimes, while safely expanding hosting capacity. Key challenges are curtailment predictability, compensation, and alignment with emerging market platforms. Clear, standardised regulatory frameworks and interoperable digital solutions are essential for scaling these agreements and accelerating DER integration.

Spanish layman's summary:

 

Este artículo presenta una revisión de los principales tipos de acuerdos de conexión a red no firmes (flexibles) existentes y del panorama regulatorio en las jurisdicciones más relevantes dentro y fuera de la UE.

English layman's summary:

This article presents a review of the main existing types of non-firm (flexible) grid connection agreements and of the regulatory landscape in the most relevant jurisdictions within and outside the EU.

DOI reference: https://doi.org/10.1007/s40518-025-00268-7

Published on paper: December 2025.

Published on-line: August 2025.

Citation:
M. Romeo Monterde, E. F. Álvarez, M. Valarezo, "Non-Firm Grid Connections: A Review of Access Types, Mechanisms, and Regulatory Frameworks", Current Sustainable/Renewable Energy Reports, Vol. 12, nº. 1, pp. 23, December 2025. [Online: August 2025] doi: 10.1007/s40518-025-00268-7