Pursuant to the notice of proposed rulemaking (NOPR) issued by the Federal Energy Regulatory Commission (FERC or Commission) on December 22, 2005,1 the Interstate Natural Gas Association of America (INGAA) submits the following supplemental reply comments in the above captioned proceeding. These supplemental reply comments respond to several points raised in the recently filed reply comments of Enstor Operating Company, LLC (Enstor),2 an independent storage provider, and the Natural Gas Supply Association (NGSA).3 INGAA recognizes that the Commission’s NOPR did not specifically provide for replies or supplemental reply comments, but respectfully submits that supplemental reply comments are appropriate and would aid the Commission in its deliberations.