Researchers at M.I.T. have found that the energy output from solar photovoltaic cells on a given base area can be increased by between 2 and 20 times by stacking the cells in 3D configurations like towers or cubes.

The designs are ideal for placing on top of tall buildings which have limited roof space.

The 3D designs increase electricity output, not only because there is more surface area, but also because their angled surfaces allow them to capture sunlight when the sun is ia at a low angle in mornings and evenings and when sunlight is scattered partial cloud cover. This results in a more uniform and predictable power output, which means that solar power can be better integrated into power grids.

While these designs will be more expensive to manufacture, solar cells are now less expensive than the accompanying support structures, wiring and installation. As the cost of the cells themselves continues to decline more quickly than these other costs, the relative advantages of 3-D systems will grow.

Although computer modeling showed that the biggest advantage would come from complex shapes – such as a cube where each face is dimpled inward – the researchers are focusing on the tower design because it can be shipped flat and popped up during installation.