Sitting in his office, Joseph Kelliher, chairman of the Federal Energy Regulatory Commission, does not seem bothered by political noise in Congress, just a few blocks away in Washington DC.

Ever since hedge fund Amaranth revealed multi-billion-dollar losses in the over-the-counter natural gas markets last year, concern has been growing among some US lawmakers as to whether Ferc and other federal regulators have adequate powers to detect and prevent manipulation in the physical energy and OTC derivatives markets.