Some Taiwan-based monocrystalline silicon solar cell makers have been developing bi-facial cells with the front side absorbing direct sunlight and the back side sunlight reflected from the ground, according to industry sources.
For a P-type monocrystalline bi-facial solar cell, the front side can generate power at an energy conversion rate of 19% and the back side at % to reach a total energy conversion rate of 20%, the sources said.
For an N-type monocrystalline bi-facial solar cell, the energy conversion rates for the front and back sides are 20% and 3% respectively, and the total rate is 23%, the sources indicated, adding production of bi-facial cells entails only small modification of existing manufacturing equipment.
However, other makers questioned the practicality of the cells. They argued that in order for both sides of the solar cell to absorb sunlight, PV modules have to be installed at certain angles, supporting floor panels have to made of selected materials and maintenance cost of the PV system is much higher.
In many places around the world, front-side sunlight absorption negatively affects back-side sunlight absorption and vice versa, they said. Because of sunlight angles, bi-facial solar cells may be more suitable for high-latitude locations, they indicated.
