What 100% Clean Power Actually Costs: Evidence From Great Britain's Electricity System

ABSTRACT

Building wind farms and solar panels is getting cheaper, but powering an entire country on clean electricity requires much more: thousands of kilometres of new transmission, storage to manage variability, and real‐time balancing to hold the system together when the wind drops. These costs rarely feature in headline figures, yet they are what consumers actually pay. This paper asks what the cost to households and businesses will be of Great Britain's Clean Power 2030 (CP2030) pathway, with at least 95% low‐carbon generation, with wind and solar supplying roughly four‐fifths of the mix. It develops the forward consumer bill model (FCBM), a structural framework that projects the complete consumer electricity bill under that pathway. Building on the total energy system consumer cost framework, the FCBM traces all 10 layers of the bill, from generation and contracts for difference settlement through transmission, distribution, balancing, long‐duration storage, capacity and legacy policy levies to decommissioning, and maps each to its actual cost‐recovery instrument. Crucially, these layers do not simply add up. As variable renewable penetration rises, they interact through shared system‐state drivers, and treating them as independently additive biases the total.