Southeast air-conditioning demand is set to drop sharply over the Labor Day weekend as thunderstorms sweep down the Atlantic coast, easing strain on natural gas pipelines that have been operating under operational flow orders (OFO) while spot prices climbed above $7/MMBtu.

The approaching storm system is expected to bring cooler conditions and clouds to the Southeast and Mid-Atlantic, reducing the need for air conditioning at a time when pipelines in the region have been stretched by persistent late-summer heat. Cooler weather typically reduces cooling-degree-day (CDD) totals, which serve as a proxy for air-conditioning demand and, by extension, natural gas consumption at power plants. Power burn is the largest single source of US natural gas demand during the summer months, which is why weather-driven swings in cooling load translate quickly into changes in pipeline throughput.

At a Glance:

• Transco Zone 5 CDDs dip Monday
• Transco OFO runs through Saturday
• US CDDs stay above normal over the next 15 days

Transcontinental Gas Pipe Line (Transco), the nation's largest-volume interstate natural gas pipeline system by delivered volumes, has had an OFO in effect covering its system, including Zones 4 and 5 in the Southeast and Mid-Atlantic. Such orders are designed to keep pipeline flows balanced with actual consumption, and shippers that deliver more or less gas than they take out during an OFO can face penalty charges, giving them an incentive to keep their receipts and deliveries aligned. The scheduled end of the Transco OFO on Saturday coincides with the arrival of the holiday-weekend storms. Cooling-degree-day forecasts for Transco Zone 5, a region that includes parts of the Southeast and Mid-Atlantic, are expected to dip Monday as the weather system moves through.

Even so, national forecasts indicate that US CDDs are likely to remain above normal over the next 15 days, meaning demand for natural gas for cooling may stay elevated even as the Southeast gets a temporary reprieve. Spot natural gas prices at locations served by pipelines under OFO restrictions have recently climbed above $7/MMBtu, reflecting the tight conditions created by strong cooling demand and pipeline operational constraints. For context, spot prices at major US hubs in mid-2024 have generally traded well below that level, underscoring how localized constraints and late-summer heat can push regional prices far above national benchmarks.

The article was reported by Chris Newman for Natural Gas Intelligence. Newman joined NGI in October 2023 after 18 years at Argus Media, where he covered US thermal and coking coal markets and rail transportation, and later helped lead Argus' coverage of steel and its raw material feedstocks from Singapore.