There is often quite a difference between the performance figures you can achieve from devices working in laboratory-controlled environments and what you can expect when they are mass-produced and operated outside, in real-world conditions. This is especially true of the solar cell technology. Although you often read reports of new designs achieving record levels of efficiency the truth is the maximum you can expect from an installation using panels available today is somewhere between 12% and 18%. Improvements using exotic materials or manufacturing processes often never get to see the light of day. A system designed and tested by the Swiss start-up Insolight has achieved a record-breaking 29% efficiency.

The type of cells used in the Insolight system have been selected for their high energy yield and are the same type used in satellites. They are of course not the cheapest but they do not need to cover the total panel area. Their system overlays the cells with a glass ‘lensing panel’ which concentrates the available light to form an array of ‘light-pools’ focussed on the cells. The solar panel is continually shifted by a few millimetres in the X-Y plane to align the cells with the points of focus to optimise power output. This means that only 0.5% of the panel area actually needs to be covered with active PV cells, reducing costs enormously. The savings far exceed the additional cost of the glass lens panel and tracking system.
 
The Insolight installation has been out in all weathers on the EPFL rooftop in Switzerland for the past year and achieved record-breaking yields. Image: Insolight.
According to Insolight, their system is particularly suitable for capturing diffuse light, which is common in Central Europe. The concept was first installed in 2016 and the company plans to have the system market-ready for 2022 after more extensive tests of the system’s durability.