If you’ve ever carried a solar panel you’ll know that they’re pretty heavy (about 25kg for a 1.5sqm panel), and if you add on the racking that’s required it makes things even heavier. This is a bit of a problem for roofs that can’t support large weights, and for the installers who have to get the stuff up there.
As with many things in life however, technology has a solution on the way. In this case the solution comes in the form of flexible solar panels. This new type of solar panel doesn’t use glass as the supporting material; it uses transparent, flexible plastic sheets. They can be rolled up like carpets and unfurled across a low-sloping roof. This process is much quicker and easier than normal solar panel installation. The solar panels just need to be tacked down at the edges, rather than have heavy metal racking bolted into the frame of the roof. The material is also light enough so that any roof can support its weight.
This technology is spreading quickly but has yet to win dominance in the market. This is for several reasons. Firstly – only one company in the world is making flexible solar panels in large volumes. That company is UniSolar, based in Michigan, USA. UniSolar have developed their own proprietary process for depositing thin-film solar cells (see discussion “REF TO previous article”) on flexible plastic sheets.
In order to increase efficiency of the panels, their design in fact uses three solar cells stacked one on top of the other. Each solar cell responds to a different part of the sun’s spectrum so it maximizes the amount of energy converted to electricity. Despite this compmexity, these solar panels are significantly less efficient than traditional, crystalline silicon solar panels. They are made from ‘amorphous’ silicon and are currently around 6-8 percent efficient, compared to 16 percent for crystalline silicon panels. This means you have to cover a larger area of the roof.
A number of companies claim to have more efficient versions of the technology on the way. Companies such as US based Advent Solar, claim to have flexible solar panels that will soon reach over 10 percent efficiency while other companies, such as G24 Innovations in Wales claim to have lower manufacturing costs for this technology.
Given the success of UniSolar with their low efficiency and complex design, any company that can make an improvement is likely to have success with flexible solar panels. Let’s wait and see…