TSP Name: Northern Natural Gas Company TSP: 784158214 Notice ID: 108617 Notice Type: Planned Service Outage Subject: PLANNED SERVICE OUTAGES - JUNE 2026 THROUGH OCTOBER 2026 Location: MARKET AND FIELD AREA Critical: N Post Date/Time: 06/24/2026 08:25 AM Notice Status: Supersede Prior Notice: 108246 For Gas Day(s): 06/23/2026 - 10/31/2026 Notice Effective Date/Time: 06/24/2026 08:25 AM Notice End Date/Time: 11/01/2026 08:59 AM Required Response Indicator Description: 5-No response required Notice Text: Northern has scheduled the service outages that will affect operating capacity within the months of June 2026 through November 2026. Please review the Planned Service Outage Summary for detailed information related to each outage. A brief description of the most recent change(s) to the Planned Service Outage Summary follows. Market/Field Area Combined Allocation Group(s)/Point(s): Field to Demarc (Group 831) and Beatrice North (Group 832) Location: Northern's pipelines and compressor stations located between the Mullinville, Kansas, and Ogden, Iowa, compressor stations Project Description: Compressor station and pipeline maintenance Month: June 2026 through November 2026 Direction of Flow: Delivery: Field to Demarc (Group 831) and Beatrice North (Group 832) Capacity Impact: Northern does not anticipate primary firm service will be impacted for Field to Demarc (Group 831) and Beatrice North (Group 832). Revision: Capacity impacts for Field to Demarc (Group 831) and Beatrice North (Group 832) have been updated for July 2026 and August 2026. Capacity impacts for Field to Demarc (Group 831) and Beatrice North (Group 832) have been included for November 2026. Market Area Allocation Group(s)/Point(s): Carlton South (Group 811) Location: Near Willow River, Minnesota Project Description: Pipeline repair on the North Branch, Minnesota, to Carlton, Minnesota, mainline Month: June 2026 through October 2026 Direction of Flow: Receipt: Carlton South (Group 811) Capacity Impact: Northern does not anticipate primary firm service will be impacted for Carlton South (Group 811). Revision: Capacity impacts for Carlton South have been included for November 2026. Allocation Group(s)/Point(s): North Branch North (Group 835), North Branch Receipt Points (Group 1151), Viking Chisago/Isanti (POI 196), Viking Pierz ITE (POI 61667), GRLKS/NNG Carlton (POI 388), GRLKS/NNG Wakefield (POI 78994), GRLKS/NNG Grand Rapids (POI 21972), SEMCO Marquette M-35 (POI 79374) and SEMCO Marquette Emergency Receipt (POI 79379) Location: Northern's pipeline between Hugo, Minnesota, and North Branch, Minnesota. Project Description: Pipeline maintenance Month: June 2026 and July 2026 Direction of Flow: Receipt: North Branch North (Group 835) and North Branch Receipt Points (Group 1151) Delivery: North Branch North (Group 835), Viking Chisago/Isanti (POI 196), Viking Pierz ITE (POI 61667), GRLKS/NNG Carlton (POI 388), GRLKS/NNG Wakefield (POI 78994), GRLKS/NNG Grand Rapids (POI 21972), SEMCO Marquette M-35 (POI 79374) and SEMCO Marquette Emergency Receipt (POI 79379) Capacity Impact: Northern does not anticipate primary firm service will be impacted for North Branch North (Group 835) and North Branch Receipt Points (Group 1151). Primary firm service will not be impacted for Viking Chisago/Isanti (POI 196), Viking Pierz ITE (POI 61667), GRLKS/NNG Carlton (POI 388), GRLKS/NNG Wakefield (POI 78994), GRLKS/NNG Grand Rapids (POI 21972), SEMCO Marquette M-35 (POI 79374) and SEMCO Marquette Emergency Receipt (POI 79379). Revision: Capacity impacts for North Branch Receipt Points (Group 1151) have been updated for July 2026. Capacity impacts for Viking Chisago/Isanti (POI 196), Viking Pierz ITE (POI 61667), GRLKS/NNG Carlton (POI 388), GRLKS/NNG Wakefield (POI 78994), GRLKS/NNG Grand Rapids (POI 21972), SEMCO Marquette M-35 (POI 79374) and SEMCO Marquette Emergency Receipt (POI 79379) have been included for July 2026. Allocation Group(s)/Point(s): Waterloo East (Group 773), Earlville East (Group 487), Galena East (Group 463) and Belleville East (Group 488s) Location: Northern's pipelines and compressor stations between Waterloo, Iowa, and Belleville, Iowa Project Description: Compressor station and pipeline maintenance Month: June 2026 through October 2026 Direction of Flow: Delivery: Waterloo East (Group 773), Earlville East (Group 487), Galena East (Group 463) and Belleville East (Group 488) Capacity Impact: Northern does not anticipate primary firm service will be impacted for Waterloo East (Group 773), Earlville East (Group 487), Galena East (Group 463) and Belleville East (Group 488). Revision: Capacity impacts for Waterloo East (Group 773), Earlville East (Group 487), Galena East (Group 463) and Belleville East (Group 488) have been updated for August 2026 and September 2026. Field Area Allocation Group(s)/Point(s): Beaver North (Group 1025), Beaver C & Beaver North (Group 1080), Brownfield North (Group 1022), Pampa North (Group 1023), Beaver C System (Group 31) and Mitchell to Gaines (Group 825) Location: Northern's compressor stations and pipeline between Florey, Texas, and Mullinville, Kansas Project Description: Compressor station and pipeline maintenance Month: June 2026 through August 2026 Direction of Flow: Delivery: Beaver North (Group 1025), Beaver C & Beaver North (Group 1080), Brownfield North (Group 1022) and Pampa North (Group 1023) Receipt: Beaver C System (Group 31) and Mitchell to Gaines (Group 825) Capacity Impact: Primary firm service will be impacted for Brownfield North (Group 1022) and Mitchell to Gaines (Group 825). Northern does not anticipate primary firm service will be impacted for Beaver C and Beaver System North (Group 1080) and Pampa North (Group 1023). Primary firm service will not be impacted for Beaver North (Group 1025) and Beaver C System (Group 31). Revision: Capacity impacts for Beaver C & Beaver North (Group 1080), Brownfield North (Group 1022) and Pampa North (Group 1023) have been updated for July 2026. Capacity impacts for Beaver North (Group 1025), Beaver C & Beaver North (Group 1080), Brownfield North (Group 1022), Pampa North (Group 1023), Beaver C System (Group 31) and Mitchell to Gaines (Group 825) have been included for August 2026. Allocation Group(s)/Point(s): Sunray Low (Group 10), Sunray High (Group 32) and ETC Sunray Plant (POI 58676) Location: Northern's compressor station located in Sunray, Texas Project Description: Compressor station and pipeline maintenance Month: June 2026 through August 2026 Direction of Flow: Receipt: Sunray Low (Group 10), Sunray High (Group 32) and ETC Sunray Plant (POI 58676) Capacity Impact: Primary firm service will be impacted for Sunray Low (Group 10) and ETC Sunray Plant (POI 58676). Northern does not anticipate primary firm service will be impacted for Sunray High (Group 32). Revision: Capacity impacts for Sunray Low (Group 10) and Sunray High (Group 32) have been updated for July 2026 and August 2026. Capacity impacts for ETC Sunray Plant (POI 58676) have been included for July 2026. Allocation Group(s)/Point(s): Seminole Subsystem (Group 598) Location: Northern's compressor station located in Kermit, Texas Project Description: Compressor station maintenance Month: August 2026 Direction of Flow: Delivery: Seminole Subsystem (Group 598) Capacity Impact: Primary firm service will not be impacted for Seminole Subsystem (Group 598). Allocation Group(s)/Point(s): El Paso/NNG Waha (POI 57100), Permian Highway Waha (POI 79489), GCX/NNG Waha (POI 79415), Oasis/NNG Waha (POI 62148), Trans Pecos Hub (POI 79311) and OneOK Westex Reeves (POI 152) Location: Northern's pipeline south of Kermit, Texas Project Description: Compressor station maintenance Month: August 2026 Direction of Flow: Delivery: El Paso/NNG Waha (POI 57100), Permian Highway Waha (POI 79489), GCX/NNG Waha (POI 79415), Oasis/NNG Waha (POI 62148), Trans Pecos Hub (POI 79311) and OneOK Westex Reeves (POI 152) Capacity Impact: Primary firm service will be impacted for Permian Highway Waha (POI 79489), GCX/NNG Waha (POI 79415), Oasis/NNG Waha (POI 62148) and OneOK Westex Reeves (POI 152). Northern does not anticipate primary firm service will be impacted for El Paso/NNG Waha (POI 57100) and Trans Pecos Hub (POI 79311). Please see Operationally Available Capacity on Northern's website for current flow information and the Field Area Group Allocation Maps andMarket Area Group Allocation Maps for a list of impacted points. If you have any questions, contact your customer service or marketing representative.