A team of MIT researchers is building cubes or towers that extend solar cells upward in three-dimensional configurations. The results from the structures they’ve tested show power output ranging from double to more than 20 times that of fixed flat panels with the same base area.
The biggest boosts in power were seen in the situations where improvements are most needed - in locations far from the equator, in winter months, and on cloudier days. The MIT team initially used a computer algorithm to explore an enormous variety of possible configurations, and developed analytic software that can test any given configuration under a whole range of latitudes, seasons, and weather. Then, to confirm their model’s predictions, they built and tested three different arrangements of solar cells on the roof of an MIT laboratory building for several weeks.
While the cost of a given amount of energy generated by such 3D modules exceeds that of ordinary flat panels, the expense is partially balanced by a much higher energy output for a given footprint, as well as much more uniform power output over the course of a day, over the seasons of the year, and in the face of blockage from clouds or shadows. These improvements make power output more predictable and uniform, which could make integration with the power grid easier than with conventional systems.
The basic physical reason for the improvement in power output — and for the more uniform output over time — is that the 3D structures’ vertical surfaces can collect much more sunlight during mornings, evenings, and winters, when the sun is closer to the horizon.