Reuters: A World Bank investment in a Russian polysilicon producer this week will help expand supplies of the key ingredient used to make solar cells and bring down costs of solar energy, an official said on Friday. The bank’s International Finance Corp this week announced it had brought a $50 million equity stake in Nitol and provided a $25 million loan to the company to help establish new production facilities in Usoliye Sibirskoye, in southeastern Siberia. Lance Crist, a senior …