Energy systems optimisation models are a leading tool for informing decisions in the energy transition. However, these models often remain opaque, and results are frequently presented without a clear discussion of their epistemic limitations. We propose Diagnostic Modelling as a framework wherein modellers critically interrogate their models and explore uncertainties to uncover mechanistic explanations that offer policy-relevant insights. Mechanistic explanations provide fundamental understanding that remains valid despite model uncertainty and does not depend on detailed knowledge of a specific model. By adopting a more open and transparent approach to engaging with energy systems models, Diagnostic Modelling encourages the participation of a broader range of decision-makers, thereby building consensus in support of the energy transition.
@article{arxiv.2604.19676,
title = {Diagnostic Modelling: a framework of principles for responsible energy systems modelling},
author = {I. David Elder and Juan Moreno-Cruz and Cameron Wade and Sylvia Sleep and Sara Hastings-Simon and Sean McCoy and Heather L. MacLean and I. Daniel Posen},
journal= {arXiv preprint arXiv:2604.19676},
year = {2026}
}