In discussing the impact of Federal Energy Regulatory Commission (FERC) Order 636, the latest rule on the restructuring and deregulation of the US natural gas industry, the effect of interest rates on the success of the FERC policy is often overlooked, The thesis of this paper is that interest rates play an important role in integrating seasonal gas markets and in stimulating investment in storage infrastructure, We propose a model to analyse the equilibrium condition for an efficient gas market, Also analysed are the implications of pipeline rate design of FERC 636 for gas despatch decisions.