Renal agenesis. Renal agenesis is a medical condition in which one (unilateral) or both (bilateral) fetal kidneys fail to develop.
Polycrystalline cells are composed of multiple silicon crystals, which is a cheaper way to manufacture solar modules. Put simply, these cells are easier for a factory to produce, so they are less expensive. Polycrystalline cells are made by several methods, but most commonly with a cast of molten silicon.
Silicon Material. Polycrystalline wafers are made by a casting process in which molten silicon is poured into a mould and allowed to set. Then it is sliced into wafers. As polycrystalline wafers are made by casting they are significantly cheaper to produce, but not as efficient as monocrystalline cells.