Barclays says it will contest a fine of 453m dollars levied on the bank and its traders for manipulating energy prices in the US from 2006 to 2008.The record penalty, equal to £298m, outstrips the total of $360m Barclays was fined in the US last year for rigging the inter-bank lending rate.The Federal Energy Regulatory Commission (FERC) said late on July 16th that the bank and the traders built up and then "flattened" physical market positions to alter the index price to benefit the bank's financial swap positions.Barclays was ordered to pay $435m in civil penalties. Scott Connelly, one of the traders, was told to pay $15m and three others were fined $1m each. All the traders have since left Barclays with the last departure in 2010.The FERC said: "Respondents traded fixed price products not in an attempt to profit from the relationship between the market fundamentals of supply and demand, but instead for the fraudulent purpose of moving the index price at a particular point so that Barclays' financial swap positions at that same trading point would benefit."The regulator said communications between the traders confirmed the scheme and showed they were taking "affirmative, coordinated, concerted, and intentional actions". But Barclays said it was innocent and that the FERC's account was one-sided and inaccurate. Its refusal to pay the fine is unusual because banks usually accept regulatory punishment however unwillingly.Barclays said: "We believe the penalty assessed by the FERC is without basis, and we strongly disagree with the allegations made by FERC against Barclays and its former traders in the FERC's order assessing civil penalty. We believe that our trading was legitimate and in compliance with applicable law. "The order assessing civil penalty is by its very nature a one-sided document, and does not reflect a balanced and full description of the facts or the applicable legal standard. We have cooperated fully with the FERC investigation, which relates to trading activity that occurred several years ago. We intend to vigorously defend this matter."The Libor scandal helped drive out former Chief Executive Bob Diamond and Chairman Marcus Agius after a series of run-ins with regulators. Barclays is under new management and is trying to clean up its image.A few hours before the FERC fine was announced, Barclays said it would replace Finance Director Chris Lucas in February next year.