Norway's national football stadium has the world's largest vertical solar roof – new solution for northern regions, yielding 20% more energy than traditional panels

At first glance, the panels look fragile, and one might worry about stepping on them. But during a visit to the stadium, we quickly learn that they are incredibly efficient in generating solar power.

Shouldn't the word "but" imply something contrary to the initial clause? These two characteristics are not exclusive to each other...

As I was reading this I thought, 'why don't they paint the roof white, wouldn't that boost power generated?' But since they hadn't, I assumed there was a good reason the roof wasn't painted white. Perhaps it didn't work. Then I read this:

Vertical PV panels also benefit from the albedo effect, where snow falling between the rows reflects sunlight on

So perhaps they just don't paint it white because white paint isn't as reflective as snow or it isn't cost efficient? Maybe the white paint will dirty?

But later it says:

The company observed how its product performs in southern regions as well. “It performs well, especially when paired with white coloured roofs, which is highly reflective and which are common in hotter, sunnier countries to reduce heat absorption,” notes Mongstad.

So now I'm even more confused why they don't paint the roof white? I thought perhaps it was for heat absorbtion, but... It's a stadium, so it's not exactly like they're using that heat to heat the building.