Norway’s $900 billion sovereign wealth fund, the world’s biggest, excluded Duke Energy Corp. and some units from its investments because of a risk of “severe environmental damage.” The executive board of Norges Bank, which oversees the fund, decided to exclude the largest U.S. utility owner by market value and its wholly-owned subsidiaries Duke Energy Carolinas LLC, Duke Energy Progress LLC, and Progress Energy Inc. after an April 5 recommendation from its Ethics Council, Norges Bank Investment Management said in a statement on Wednesday.