U.S. Deputy Energy Secretary Daniel Poneman

U.S. Deputy Energy Secretary Daniel Poneman

Gustavo Graf/Bloomberg

In a letter Oct. 8 to Daniel Poneman, deputy secretary of the U.S. Department of Energy, Constellation said it received a government estimate that the venture would have to pay about $880 million to the U.S. Treasury for the loan guarantee, “dramatically out of line with both our own independent assessments and of what the figure should reasonably be.”