It is recognised that on-site renewable and low carbon energy technologies will have a roll to play in achieving nationally prescribed standards on new development sites. However, we consider that this all needs to be subject to feasibility and viability testing - a crucial caveat that needs to be mentioned in the preferred option, consistent with Para 96 of the NPPF. District heating is one technology to consider amongst many, and whilst it may be technically feasible for larger mixed use sites, the up front capital costs, complexities regarding implementation for phased developments and lack of experience in setting up these networks for residential-led schemes in the UK are significant challenges.