Developed by Kyosemi Corporation, Sphelar solar cells are one of the most intriguing solar solutions that we have seen in a while. On display at the recent PV Expo 2010 in Tokyo, these tiny spherical cells gave us a glimpse of how windows in buildings might be used to collect solar power in the not-so-distant future.

Sphelar cells are solidified silicon drops measuring 1.8 mm in diameter and are highly transparent, which is advantageous for a number of reasons. They can be embedded in glass to create a transparent solar cell window, capable of absorbing light from any direction or angle. Because both sides of the glass can collect light, this should translate into highly efficient energy harvesting.

The cells can also be embedded in flexible surfaces, allowing for them to take on unusual shapes or be bent if necessary. The Sphelar Dome is one such example, designed to absorb more energy in the early morning and late evening unlike a flatter design.

Have we seen the last of roof-mounted solar panels? It's exciting to think that a day may come when these 'power windows' could be in buildings everywhere, integrated into existing structural designs.