For those looking to reduce emissions, utility costs, and increase energy independence, from residences to entire countries, solar panel arrays are one a popular solution.
On the other hand, solar panels could be more efficient, and average mass-market commercial panels are typically around 15% efficiency. The rest of the sun’s energy is lost to heat and reflection, not to mention the effects of weather and daily cycles. Much research has gone into improving solar panel efficiency, much of that with regards to the solar cells themselves. On the other hand, good old optical improvements can also go a long way toward improving solar panel efficiency.
Another part of solar panel efficiency that can’t be ignored has to do with keeping them facing the sun. Obviously, a solar panel directly facing the sun, perpendicular, will generate more electricity than one at an angle, but that introduces an expensive problem. Because the sun, at least to our perspective and that of our solar panels, moves across the sky, the most efficient way to capture its light is to track that movement across the sky, requiring expensive and energy-intensive motorized tracking systems. Less expensive, as well as less efficient, is to mount solar panels in an average position that may reach peak efficiency only once a day, or even once a year.
One solution, recently developed by Glint Photonics, could significantly increase solar panel efficiency while at least reducing the need for solar tracking. The adaptive optical coating changes reflectivity with temperature, temperature across different parts of the coating being dependent on the rays of the sun. How it works is that the part of the coating facing the sun heats up, becoming transparent and allowing the rays to enter. The rest of a the coating, being relatively cooler, remains reflective, so sunlight entering bounces around until it hits the solar cell beneath. As the angle of the sun changes, the coating’s reflective and transparent sections also change, maximizing solar panel efficiency without changing the physical angle of the panel. Glint suggests that, if their technology could be commercialized, it could cut the cost of solar power in half, from 8 ¢/kWh to 4 ¢/kWh.
Image © Glint Photonics