Principality Stadium goes green with 3,000 solar panels on its roof

The Welsh Rugby Union (WRU) has spent around £1m putting more than 3,000 solar panels on the roof of the Principality Stadium in Cardiff, describing it as a "win-win" for fans.

The WRU said the installation, which is the largest of its kind at any sports stadium in the UK, would save between £300,000 and £400,000 on energy bills every year.

At a time when the Union is under scrutiny over its plans to cut a regional rugby side, Gavin Marshall, the WRU's chief operating officer, said the investment made financial sense.

The stadium, home of Welsh national rugby, has hosted high profile gigs from the likes of Taylor Swift, Beyoncé, Oasis and Coldplay.

Tinkering with such an iconic building could be risky but the work has been done "sympathetically" according to Darren Crossman, head of facilities and safety at the stadium.

The 3,296 panels were driven through the stadium's large access tunnel, known as the Dragon's Mouth, before being placed on the covered pitch and lifted onto the roof with a huge crane and then connected, in a process which took months.

"You can't see them from the ground level but what we've tried to do is make a mirror image on both sides of the stadium so that there's nothing hideous up here," he said.

Evoenergy, the company behind the project, said it would generate enough electricity to power the equivalent of 50 match days.

The panels, covering 6000m², have been switched on since February and while direct sunlight itself is not needed for energy to be generated, the recent heatwave gave the "best couple of weeks".

"We were generating in excess of 800 kilowatts," said Darren.

"So the stadium was actually off-grid for most of the day, during the day, and exporting power as well, which is something we hadn't actually dreamed of being able to do."

The union believes the technology could pay for itself quicker than the three-four years originally projected.

"The results have been have been great and we'll get payback within two to three years for the investment we've made," said Gavin, adding that hundreds of thousands of pounds saved on energy bills would be "reinvested back into Welsh rugby."

"It's a win-win from a financial and an environmental perspective," he said.

An increasing number of sporting venues have already added solar panels to their buildings, including the London Stadium and the grandstand at Ascot Racecourse.