Item 2. Properties
We consider our properties to be well maintained, in good operating condition and suitable for their intended purpose. The following provides the location and general character of the materially important properties that are used by our segments.
Distribution and transmission assets This property primarily includes assets used by our distribution operations and energy investment segments for the distribution of natural gas to our customers in our service areas, and includes approximately 46,000 miles of underground distribution and transmission mains. These mains are located on easements or rights-of-way which generally provide for perpetual use.
Storage assets We have approximately 7.5 Bcf of LNG storage capacity in five LNG plants located in Georgia, New Jersey and Tennessee. In addition, we own three propane storage facilities in Virginia and Georgia that have a combined storage capacity of approximately 1 Bcf. These LNG plants and propane facilities are used by distribution operations to supplement the natural gas supply during peak usage periods.
We also own a high-deliverability natural gas storage and hub facility in Louisiana. This facility is operated by a subsidiary within our energy investments segment and includes two salt dome gas storage caverns with approximately 10 Bcf of total capacity and about 8 Bcf of working gas capacity. Our energy investments segment also owns a propane storage facility in Virginia with approximately 0.3 Bcf of storage capacity. This facility supplements the natural gas supply to our Virginia utility during peak usage periods.
Telecommunications assets AGL Networks, a subsidiary within our energy investments segment, owns and operates telecommunications conduit and fiber property in public rights-of-way that are leased to our customers primarily in Atlanta, Phoenix and Charlotte. This includes over 184,000 fiber miles, a 55,000 mile increase compared to 2008. Approximately 44% of our dark fiber in Atlanta, 25% of our dark fiber in Phoenix and 4% of our dark fiber in Charlotte has been leased.
Offices All of our segments own or lease office, warehouse and other facilities throughout our operating areas.We expect additional or substitute space to be available as needed to accommodate expansion of our operations.