Researchers have been trying to develop double-sided solar cells that can capture both direct and reflected sunlight for the last forty years, and now an Israeli startup believes they have come up with the winning formula. bSolar, a venture-backed project founded in 2007, showcased their bifacial solar cells at a trade show in Germany last month. According to Yossi Kofman, co-founder and CEO, their cells could produce up to 20% more energy than conventional cells. But it won’t be easy.
The challenge of double-sided solar cells:
As Bhushan Sopori, a researcher at the National Renewable Energy Laboratory told GigaOm, there’s a reason that bifacial solar cells have not been successful to date. Boron is the main component of the bSolar bifacial cell that allows the silicon wafers to capture reflected light on both sides. Although aluminum has historically been used to prevent the loss of electrodes when convert sunlight into electricity, boron won’t bend or break increasingly thin silicon wafers. Plus this chemical element increases efficiency.
But boron is hard to source and hard to use in production. For help understanding why, we’ve included a little clip from our friend Wikipedia:
Because boron is produced entirely by cosmic ray spallation and not by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth’s crust. However, boron is concentrated on Earth by the water-solubility of its more common naturally occurring compounds, the borate minerals. These are mined industrially as evaporites, such as borax and kernite.
If bSolar can find a way to source boron, which creates a strong, lightweight and refractory compound that is resistant to thermal shock, then they might be successful. But they have to make their efficiency gains cost competitive as well. More