In this white paper, Senior Managing Director George Anstey, Senior Consultant/Principal Kardin Sømme, and Analyst Leonie Wellié comment on the pivotal moment facing Ofgem in its first application window for cap and floor (C&F) support for Long Duration Electricity Storage (LDES). Ofgem intends to publish its initial decision on the award of a C&F for LDES at some point during Spring 2026, with plans to procure between 2.7 and 7.7 GW of storage capacity in this first application window. 

Drawing on experience from the interconnector regime, the authors highlight that the assessment process involves complex modelling and multiple criteria, which require careful consideration of various assumptions and methodologies. They observe that these factors can influence project evaluations and outcomes, underscoring the importance of transparency and thorough analysis in the decision-making process.

Ofgem’s multi-criteria assessment (MCA) of LDES projects is opaque, which will make it difficult for project developers to reconcile and scrutinize its results, and Ofgem and the National Energy System Operator (NESO) retain a high level of discretion over each project’s outcome across assessments. The paper underscores the importance of stakeholder engagement, noting that winning a C&F may hinge not only on the quality of the project but also on the quality of the evidence presented.

This analysis offers critical insights for developers, investors, and policymakers as Ofgem moves toward its shortlist and final awards, emphasizing the complexities inherent in the current regulatory framework for LDES.