Given the complexities of modelling DG, the exercise is necessarily rather assumption-driven. As a result, there are significant uncertainties associated with the ‘rule of thumb’-type assumptions made in the study. For example, the authors note that the WADE framework incorporates a single cost to reflect the cost of infrastructure updates required for transmission and distribution under each of the DG and CG scenarios. In practice, however, such costs vary significantly from project to project. Furthermore, the model adopts averysimplistic treatment of CHP: although the generation sector is explicitly modelled in WADE, heat is not explicitly identified and so instead the authors attempt to quantify the benefits of better fuel efficiency associated with CHP simplistically.