Overview
The Department for Energy Security and Net Zero (DESNZ) requires accurate data on wind farm generation costs and load factors for its electricity system modelling calculations and to inform future policy. As part of due process, the methodologies DESNZ uses to derive generation costs and load factors are subject to peer review. BVGA carried out this peer review in partnership with Grant Thornton and Boxkite.
Our review covered:
- Part 1 – Offshore wind generation costs and technical assumptions
- Part 2 – Offshore and onshore wind load factors
In Part 1, we reviewed both the methodology and results from an independent analysis commissioned by DESNZ in 2024. We provided critique on the method used to obtain and process data, on the literature review used to validate results, and on the process used to derive low, mid, and high scenarios for each cost and technical assumption category. We established our own set of benchmarks for each of these categories to compare with the results of the independent analysis, and recommended changes to address areas of bias.
In Part 2, we reviewed the methodology that DESNZ had developed to estimate load factors for onshore and offshore wind farms. We identified several ways in which the methodology could be refined, including the quality of the input data sets used and the process to adjust and account for loss factors.
We presented our recommendations to senior officials at DESNZ for incorporation into future revisions of cost, technical assumptions, and load factor models. The peer review reports were published by DESNZ in January 2026.
Key challenges
- Data quality and availability
- Aligning benchmarks across technologies
- Load factor modelling complexity
- Integrating refinements into DESNZ processes
Key impact
- Improved accuracy of Government modelling
- Enhanced transparency
- Betting understanding of generation costs and load factors
BVGA team
Neil Douglas
Charlie Boal
