A report published by the Welsh government last week has raised the possibility of extending permitted development rights (PDR) for solar PV and thermal beyond current limits.

The move would echo similar rules enacted by the UK government last year, which raised PDRs for rooftop solar installations from the “outdated” 50kW limit to 1MW.

Under the changes explicit planning permission is only needed for rooftop solar installations above 1MW in size, with all installations below that capacity only requiring notification to the local planning authority.

The English solar industry said at the time that the increase would be a “shot in the arm” for commercial rooftop solar, and the Welsh government’s report has said that the change in English PDRs “would appear to be giving additional confidence to developers there”.

The report discusses various elements of planning law that currently apply to the deployment of solar installations for both electricity and heat, and how increasing the threshold from the current 50kW for PV and 45kW for heat would impact upon deployment.

It discusses several options that the Welsh government could enact, including leaving PDRs unchanged and increasing the threshold to 1MW, 3MW and 5MW.

In setting out those proposed thresholds, the report states that an increase to 1MW would address current problems within the framework hindering the market, while further increases would fit “more closely with national policy” and allow for improvements in technology.

It did however warn that there were currently no rooftop systems of this size in Wales, meaning that an increase in threshold would effectively render the process of planning approval obsolete.

The report concluded that anecdotal evidence suggested that companies in Wales had been actively choosing not “to invest in solar installations in Wales directly as a result of the current threshold based approach to solar installations”, and that bringing Welsh policy in line with that of England could help allay the problem.

It is not yet clear at what stage the Welsh government is in considering the report’s conclusions, or if an increase in PDRs within Wales is being discussed.