(Preble County, OH)--Residents of Preble and Darke County who have AES Ohio as their supplier for electricity are being told to brace for a huge increase in their monthly electric bill.  AES is the former DP&L.  An AES spokesperson said Thursday that, beginning at the first of next month, the residential supply charge will more than double.  That spokesperson blamed inflation and the situation in Ukraine for the increase.  The average residential AES customer will can expect an increase of at least $60 per month.