The INGAA Foundation recently issued a report on the need for natural gas infrastructure in the United States. It finds (in part):
To accommodate the changes in natural gas supply and demand, the U.S. and Canada will need 28,900 to 61,900 miles of additional natural gas pipeline by 2030. This will require an investment of $108 to $163 billion in pipeline assets. ***
Changes in gas supply and demand also require significant investment in gas storage. Between 2009 and 2030, the U.S. and Canada will need 371 to 598 Bcf of additional gas storage capacity. *** Much of the new storage capacity that is needed is high deliverability storage to meet the growth in gas demand for electricity generation.
You can find a copy of the report here.