Bifacial, or double-sided, solar cells are able to generate energy from direct sunlight on their front side and from reflected and diffused light on their rear side. They work in either a vertical or horizontal installation and could majorly boost the efficiency of solar power systems. They've been tinkered with for decades, but expensive materials and difficulty in manufacturing has kept them from taking off. Luckily, that could be changing.
BSolar, an Israeli solar start up company, has announced that they have produced bifacial solar cells that are high-power, high-efficiency and more affordable to manufacture. The monocrystalline silicon solar cells are made with standard equipment and production processes, which means they could be scaled up for the mass market.
According to the company, the cells "provide 10-30% higher energy (KWH) per KWp installed in standard applications and up to 50% in vertical installations, resulting in an equivalent cell efficiency of 21%-24% in standard applications and a total module power of 280-325 Watts for 60 cell modules. This unprecedented efficiency and power are amongst the industry highest for mono crystalline silicon cells."
As GigaOm reports, the secret to the double-sided solar cell is the use of boron instead of aluminum in the cell. Boron allows the rear of the cell to absorb reflected light and also boosts the efficiency of the front side of the cell. It also makes the cell more resistant to bowing or breakage, especially in thinner designs, but using boron does make solar cells more difficult to produce and more expensive.
BSolar has been able to get those costs in a competitive range considering the boosted performance of their cells. The company has landed its first project, a 730 kW installation in Japan, that will use its bifacial cells and several solar cell manufacturers will start using its cells in their modules, which means this cool technology could be finally finding its way.