Solar panels are a common sight on rooftops the world over, but what about the vertical façades of offices, apartment blocks and houses, which offer a vast and, as yet, largely untapped resource for power generation, particularly in cities where high rises dominate?
Research teams and tech innovators are aware of the potential and working to develop a range of brick- and block-based products that combine structural strength with electricity generation, electricity storage and even wastewater processing.

For the first time in hundreds of years, walls could gain new intrinsic functionality. In the following panels, we highlight four of the most promising technologies being put through their paces in the lab.

The ability to scale-up power generation across a much larger surface area than a roof alone could support a faster route to delivering energy-positive buildings, which feed surplus energy to local buildings or the grid.

Energy storage infrastructure...