An amendment to Part L of the Building Regulations will come into effect on 4 March 2027, making on-site renewable electricity generation a ‘functional requirement' for new homes and non-domestic structures. This mandate ensures solar power is integrated from the design phase rather than being added as a retrofit. The new rules state that any new residential building or building containing a dwelling must install a renewable generation system on-site.

From 2028, the mandate will extend to new roofs or material changes. Solar Energy UK has strongly welcomed the decision, noting that it brings Wales into alignment with similar standards recently proposed for England.

The mandate parallels England’s upcoming Future Homes Standard and Future Buildings Standard, which are expected to be finalised later this year. Currently, over 40% of new homes in England are already built with solar panels, according to Solar Energy UK.

‘This is tremendous news for Wales and I applaud the Welsh government for their wise decision,' said Chris Hewett, Chief Executive of Solar Energy UK. He noted that the industry has long lobbied for solar to be all but mandatory on new buildings to ensure future occupants benefit from lower energy bills.

Specific exemptions exist to prevent impractical or uneconomical installations. If a system cannot generate at least 720 kWh per year, the requirement will not apply to that specific building. A typical residential rooftop solar installation of nine 450 Watt solar panels generates about 3,500 kWh. Detailed guidance will be published later this year following a consultation to determine the feasibility of the mandate.

In a separate clean energy milestone, Great British Energy has now funded solar panel installations on 100 schools and colleges across England. Around 250 schools are expected to complete their installations by summer. This programme is estimated to save these educational institutions a combined £220mn over the lifetime of the panels.

Great British Energy and the government have noted their focus on schools clustered in areas of deprivation, including the North East and North West. At least 10 schools in every English region are receiving support through the £255mn investment, according to the Department for Energy Security and Net Zero and the Department for Education.

Minister for Education Josh MacAlister said: ‘Solar panels are not just good for the planet – they are an investment that keeps paying back into our schools and our children’s futures, and shows our children that they matter.’

Energy Secretary Ed Miliband said: ‘Our local power plan will build on this success so that by 2030, every community in the UK will have the opportunity to own and benefit from a local energy project.'