Decarbonising council buildings in Wales alone would cost at least £2.3bn, according to a new report that warns the public sector is highly unlikely to meet its 2030 net zero ambition.

Audit Wales said some public bodies that had estimated the longer-term cost of decarbonising described it as unaffordable, while many had made limited progress in understanding what it would cost in the near or longer term.

The Welsh Government declared a climate emergency in 2019 and set a ‘collective ambition’ for a net zero public sector by 2030. The watchdog said that, since its last report in 2022, there had not been the acceleration it had called for.

It found decarbonisation had become a lower priority for public bodies, partly because of financial pressures, and that skills gaps remained. The ambition was also poorly defined and criticised as ‘unachievable’, while reported emissions had increased, although better reporting coverage had played a part.

An unpublished 2025 report commissioned by the Welsh Government and Welsh Local Government Association (WLGA) and cited by Audit Wales looked at the cost of decarbonising council buildings across Wales. Estimates ranged from at least £49m in Ceredigion to at least £218m in Cardiff.

Ann-Marie Harkin, Executive Director for Audit Delivery, said: ‘We can list positive examples, but not enough progress has been made overall, and we owe it to future generations to do better.’

The report recommends the Welsh Government clarify its strategic direction, improve emissions reporting and support better financial planning.

The Welsh Government said: ‘The 2030 ambition has driven action and leadership, but it's clear that there is more work to do on decarbonisation across and beyond the public sector in Wales.

‘We will set out our future vision and priorities for public sector climate action in due course, drawing on the valuable findings and recommendations set out in the Audit Wales report.’

A WLGA Spokesperson said: 'Councils recognise the financial challenges, particularly the cost of decarbonising buildings. However, work has been done to understand the costs and identify the most effective and affordable ways forward. This work can also bring wider benefits, including cleaner air, less noise, local jobs and training opportunities, and more opportunities for local businesses.'

Watch: Cadaema’s David Parrett on getting a grip on council estates