Interruptible Gas Sales Service (IS-1) [PDF - 84 KB] – MGE provides company-owned natural gas supply on a lower-cost interruptible basis. MGE does not contract for firm interstate pipeline capacity to guarantee delivery of supply for IS-1 service, so customers taking this service are required to stop using gas when asked. As a result, IS-1 customers’ natural gas service charge is lower than the monthly FS-1 natural gas service charge. You must be able to interrupt all of the service taken under IS-1 (less your contracted FS-1 nomination). A contract is required for IS-1 service and special equipment will need to be installed at your gas meter site.