Dover, Salisbury winter gas stress record: neither rated; Columbia posted 55 critical gas days

By Sam Strong, Vice President of Business Development, Discovery Energy. Technical review by Tara Dugger, Chief Operating Officer. Published November 2, 2026.

Metro used: two metropolitan statistical areas, as the federal government defined them in Bulletin No. 23-01 (July 21, 2023): Dover, Delaware, and Salisbury, Maryland.¹ They are served through one pipeline, Eastern Shore Natural Gas Company ("Eastern Shore"), so they share this page, and each has its own section and map. Columbia Gas Transmission, LLC ("Columbia") and Transcontinental Gas Pipe Line Company, LLC ("Transco") are the two interstate pipelines whose public notices we reviewed. The Delaware and Maryland utilities are Chesapeake Utilities Corporation ("Chesapeake") and, in New Castle County, Delmarva Power & Light Company ("Delmarva").

Key takeaways

Why these two metros are not rated

We rate a metro only when a public source gives a current-year supply-versus-demand balance, and none we reviewed gives one for Dover or Salisbury. The most recent figures found are the 2017 testimony and 2018 order shown below as too old to rate. If Chesapeake states its design day margin in writing, or a filing gives one, either metro can be rated at the next update.³

Who serves each metro?

Dover is served by Chesapeake in Delaware, and Delmarva serves New Castle County, not Dover. Chesapeake's service to Kent County is not confirmed from a saved territory page. Salisbury is served by Chesapeake in Maryland. The pipeline notices name pipelines and market areas, not utilities, so each metro had to be matched to them. We matched Dover to Columbia's West Deptford market area and Downington market area, which hold delivery points of Delmarva and Eastern Shore, to the Dover area operating area and to Transco zone 6. This is an inference: Eastern Shore is the pipeline Chesapeake connects to, and Columbia lists an Eastern Shore delivery point and a Delmarva delivery point. Columbia lists no delivery point for the Salisbury area, so we could not match Salisbury to any Columbia market area or operating area. Salisbury is tied to Transco zone 6 by contract only. We made the matches from Columbia's market area and operating area descriptions and its locations report, and from the Transco locations list.³² Artemas East operating area consists of Buena Vista, Hanover, Easton, West Deptford, Lancaster and Downingtown market areas.² Eastern Shore is the pipeline that physically serves both metros, but its notices and its Index of Customers (the list of each shipper's contracts) were not reached. The Columbia and Transco counts below describe two of Eastern Shore's upstream pipelines, so they describe only part of the supply and may understate or overstate its exposure.⁶

The escalation ladders: pipeline and utility

Columbia warns in steps: operational alerts, pre-operational flow order warnings, flow orders for receipt points, and then transport critical days for named operating areas. The "critical days" counted on this page are that last step, and each carries a tariff penalty for takes above firm entitlement.² Chesapeake's tariffs set the order in which customers are curtailed (cut back) if gas is short. Chesapeake's Delaware tariff (P.S.C. Del. No. 5) orders curtailment from the lowest priority up. Priority 6, all OSSS customers, is curtailed first. Priority 5 is firm commercial and industrial customers above a stated annual use, and Priority 1 is essential human needs. The tariff also lets Chesapeake issue an operational flow order notice, with a penalty based on the higher of a Transco zone 6 or Texas Eastern zone M-3 price. Chesapeake's Maryland tariff uses the same order, with Priority 6 for interruptible customers and Priority 1 for essential human needs. These describe what the tariffs say. We did not search for or count any case where a step was declared. Eastern Shore's own tariff, including its operational flow order levels, was not reached.³

Winter by winter: distinct critical-day events in Operating Area 4

Critical days were declared for the Dover operating area in all three winters, on 24, 34 and 55 gas days.³³ A winter is 1 November to 31 March. An event is one run of transport critical-day status for the operating area, and the day it is lifted is left out. Storage critical days carry the same dates and are counted as the same events. Routine operational alerts and capacity postings are left out of the events. Operating Area 4 is the Columbia area that holds the Eastern Shore and Delmarva delivery points. The counts are for Dover's mapped area and are not a Salisbury record.

Number of separate critical-day events and gas days in the Dover operating area, by winter.²⁵

The runs behind these counts are listed below.

Each run of critical days in the Dover operating area, with its start, its lift and its gas days.²⁶

Transco imbalance orders, shown separately

These orders are a different measure from Columbia's critical days, and the two counts are not added. Transco's notices say they do not affect delivery of scheduled gas.⁴

Number of imbalance order runs and days covered in Transco zone 6, by winter.²⁷

In 2025-26 Transco issued many short notices, so run counts differ in character from earlier winters.⁸ Transco also posted force majeure notices, which announce an emergency outage or repair. One limited primary firm transportation through Station 517 on its Leidy line from December 2025, and the other did so through Station 115 in February 2026.³⁴ The notices do not state whether either reached these delivery points.⁹ Transco also posted four system-wide cold-weather operational alerts in the three winters.¹⁰

Other Columbia events naming these areas

Columbia posted force majeure events (emergency outages or repairs) that named market areas holding Dover's delivery points. Whether any customer service was affected is not stated in the notices we reviewed.⁷ The first, at Downingtown, ran from 2023-11-08 to 2023-11-16 and named the West Deptford and Conowingo market areas, whose tied metros are Washington DC, Baltimore and Dover.³⁷ Our summary of the notices is that they gave no anticipated commercial impact at posting and named constraints as possibly impacted. The second, on Line1804, ran from 2025-02-10 to 2025-02-16 and named the Hanover, Easton, West Deptford and Conowingo market areas, whose tied metros are Baltimore and Dover.³⁸ Our summary of the notices is that they gave no commercial impact at posting, listed restrictions that may become necessary, and said commercial restrictions remain after the lift.

Documented local constraints

Columbia's daily capacity postings show whether non-firm service was available through named internal constraints, and zero means none was offered through that point that gas day. This is a different measure from a critical day, because zero also occurred on days with no critical day, so it is a cold-season condition.¹¹

Days with no non-firm capacity at Columbia constraints near Dover's delivery points, out of the gas days parsed in each season.²⁸

Artemas is at zero in every season and Downingtown West is a receipt constraint, so for them zero is closer to a standing condition.¹²

Weather against normal

Winter 2023-24 was the mildest of the three at both stations and 2025-26 the coldest, yet Columbia declared critical days for Operating Area 4 in all three winters. Three winters are not enough to separate weather from how Columbia chose to use critical days.¹⁴

How cold each winter was at two weather stations, as a share of the 1991-2020 normal.²⁹

Dover uses the cooperative station because the Dover Air Force Base record has missing months.¹³ NOAA's three-month temperature outlook for each metro, issued October 15, 2026, is given in the section for that metro below.¹⁵

Firm contract end dates, and what they do not show

A contract end date is not an expiry of service. The Indexes of Customers list each shipper's firm contracts with end dates. Columbia's own capacity report assumes all right-of-first-refusal (ROFR) rights are exercised indefinitely, so a contract with that right may be renewed. The table sums transport contracts that had not passed their primary term on October 27, 2026, by the year the term ends. It shows separately contracts past their primary term, which may still run. It does not measure any utility's total firm supply: Eastern Shore's own capacity, storage on other pipelines and agent-held contracts are not in it.¹²

Firm transport contracts held by each shipper, in dekatherms (Dth) per day, grouped by the year the contract term ends.³⁰

Chesapeake's and Delmarva's contracts are not split by state or division. Eastern Shore's three Transco contracts carry storage only.¹⁶

Capacity added on Eastern Shore

Eastern Shore, the pipeline serving both metros, added firm capacity in the years covered by the records we reviewed. The Del-Mar Energy Pathway added 11,800 dekatherms (dts) per day of firm capacity. Chesapeake's Delaware Division is a shipper on it for 7,750 Dth per day and its Maryland Division for 3,000 Dth per day.³⁵ Its project page gives an in-service date of September 2021. The Southern Expansion added 7,300 dts per day of firm capacity, which Chesapeake's Delaware division said it requires to meet residential end-user growth, with an in-service date of October 2023.⁵ Chesapeake describes a Worcester Resiliency Upgrade as peak supply of up to 14,000 dts per day, and said it was expected to be operational before the winter heating season of 2025. Its current status is not confirmed. By our sum, the two completed projects add 19,100 Dth per day, and 33,100 with the Worcester upgrade. The earlier 2017 expansion authorized 61,162 Dth per day of firm capacity, including 10,000 Dth per day for Delmarva.³⁶ Added capacity is not a measure of the balance between supply and demand.¹⁷

Older figures, shown only as too old to rate

These older figures are not used to rate either metro. Testimony filed in 2017 in a Delaware Public Service Commission docket (listed in Notes) gives projected design-day demand for Chesapeake's Delaware customers of 90,363 Dth for winter 2017-18. It says projected resources exceeded that demand by 307 Dth. For 2018-19 it gives 93,781 Dth and a margin of 4,662 Dth, or 5 percent. These are testimony, not commission findings, and are eight winters old. A Delaware PSC order of 2018 gives Delmarva's projected 2017-18 design day load as 179,807 mcfd and a revised reserve margin of -4.28% after the January 2018 cold event. That is Delmarva's New Castle County system, not Dover's.³

New large gas loads

We found no new large gas load in the records we reviewed, but the siting portals could not be reached, so a large new gas load beyond the generator inventory below is not ruled out.⁶ The U.S. Energy Information Administration (EIA) monthly generator inventory (September 2026 release) lists no planned or canceled gas-fired unit in Kent County, Delaware, or in Wicomico or Somerset counties, Maryland.¹⁸ Data centers: As of October 28, 2026, we found no gas data center load on Chesapeake's, Delmarva's or the Eastern Shore pipeline's system in the official records searched.¹⁹ The Delaware commission's order of September 3, 2025 opened a large load tariff docket for Delmarva's electric service, citing a proposed data center of 1.2 gigawatts; it concerns electric service, not gas, and states no fuel or service date.²⁰ Nearby: we searched only the counties of the two metros, so this page says nothing about loads beyond them.

Policy context

No Delaware or Maryland policy, order or rule specific to natural gas service for large new loads was found in the official sources we reviewed, so none is described here. A 2025 Delaware docket on Chesapeake's gas sales service rates and a Maryland rate case hold testimony that could not be downloaded (docket numbers in Notes).⁶

Dover

Dover (Kent County, Delaware) is matched to Columbia's operating area for Dover by inference, from Columbia's Delmarva and Eastern Shore delivery points.¹² The critical-day record above is for this operating area.²¹ Transco zone 6 also holds Delmarva and Eastern Shore delivery points, and its imbalance order counts are in the table above.¹⁰ Downingtown East in market area 24 was at zero non-firm availability on most winter days. Force majeure events at Downingtown in November 2023 and on Line 1804 in February 2025 named market area 24 as possibly impacted.²¹ The public record doesn't show Chesapeake's design-day demand and firm supply for a current year, doesn't confirm from a saved territory page that Chesapeake serves Kent County, and doesn't show Eastern Shore's notices or how much of Dover's gas reaches it through Columbia's operating area 4 rather than other pipelines. Figures of 2017-18 and 2018-19 are too old to rate.⁶ For Dover, NOAA's Climate Prediction Center outlook issued October 15, 2026 leans above normal for November 2026 to January 2027 and for December 2026 to February 2027; these are NOAA's probabilities for a three-month average temperature, not a forecast of specific days or of an outage.²²

Salisbury

Salisbury (Wicomico and Somerset counties, Maryland) has no Columbia delivery point in the files we reviewed, so the Columbia critical-day record above is not a Salisbury record. Chesapeake's Maryland tariff gives a curtailment order starting from Priority 1. Its Maryland Division's Del-Mar share is in the capacity section above. Transco zone 6 contracts held by Chesapeake appear in the table above.²³ The public record doesn't show any Columbia notice count for the area; Chesapeake Maryland's design-day demand and firm supply; Eastern Shore's notices; and the Worcester Resiliency Upgrade's in-service status.⁶ For Salisbury, NOAA's Climate Prediction Center outlook issued October 15, 2026 leans above normal for November 2026 to January 2027 and for December 2026 to February 2027; these are NOAA's probabilities for a three-month average temperature, not a forecast of specific days or of an outage.²⁴

What's new (as of October 28, 2026)

No filing dated in the past 90 days was found that changes the gas record for Dover or Salisbury.¹⁹

What should facilities in these metros check now?

• Tariffs and charges, through a utility audit. Confirm each account is on the right rate class and tariff, and that riders, demand charges and capacity-related charges are billed correctly. Over 70% of the clients Discovery Energy has audited were billed incorrectly. An audit verifies tariffs and charges and recovers overcharges before winter costs rise.
• Which utility, pipeline and rate. Confirm which utility serves each site and its interruption and balancing terms, because the notices we reviewed name pipelines and market areas, not utilities.
• Backup plans and fuel. Check that alternate-fuel and curtailment plans are current and feasible, and that fuel inventories and resupply arrangements are in place before December.
• Upcoming records. Track each utility's design day statements and any supply plan filing, which would allow a rating.

Frequently asked questions

Related case studies

Discovery Energy publishes gas capacity case studies for other metros, using the same method and outlook scale.

• Detroit natural gas capacity case study (outlook: High)

All gas capacity ratings by U.S. metro

Notes

1. Metro delineation: OMB Bulletin No. 23-01 (July 21, 2023), as carried in the project's metro list and its industrial supplement file. The counties are Kent County, Delaware, for Dover, and Somerset County and Wicomico County, Maryland, for Salisbury.
2. Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012. Notice supporting the critical-day counts in the summary line and in Key takeaways item 2: Columbia Gas Transmission, LLC, Capacity Constraint Notice 25980112, February 20, 2026. ↩
3. Chesapeake Utilities tariffs for Delaware (P.S.C. Del. No. 5) and Maryland, Delmarva Power order text (Delaware PSC docket 17-1013) and testimony in Delaware Public Service Commission docket 17-1021:. Utility statements and testimony are not commission findings. ↩
4. Transcontinental Gas Pipe Line Company, LLC, critical notices, location data and Index of Customers on the Williams 1Line site, public postings downloaded October 27, 2026; facts are paraphrased and counts and tables are Discovery Energy's own. The notices say the imbalance orders do not affect delivery of scheduled gas. No verbatim Transco text is used. Notice dates are posting dates. Notice supporting the 56 gas days in Key takeaways item 3: Transcontinental Gas Pipe Line Company, LLC, Operational Flow Order Notice 16225021, November 6, 2025. ↩
5. Federal Energy Regulatory Commission orders and Eastern Shore Natural Gas Company and Chesapeake Utilities Corporation project pages, accessed October 27, 2026; sums computed. The Worcester Resiliency Upgrade status is not confirmed. Source for the 7,300 dts per day completed in October 2023 in the Capacity added on Eastern Shore section: Eastern Shore, Southern Expansion project page, accessed October 27, 2026. ↩
6. Records not found or not reached: the informational postings and tariff of Eastern Shore (esng.com's disallows automated access); Chesapeake Utilities' current design-day demand and firm supply for Delaware (the testimony in the 2025 Delaware docket 25-0834 needs a manual download) and for Maryland (Maryland PSC case 9722 returned an error to automated downloads); a Chesapeake territory page confirming Kent County (Dover); the Chesapeake Utilities Corporation 2025 annual report, read on a web page and not saved; the status of the Worcester Resiliency Upgrade; and notices of other pipelines serving the peninsula. ↩
7. Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012. ↩
8. Transcontinental Gas Pipe Line Company, LLC, critical notices, location data and Index of Customers on the Williams 1Line site, public postings downloaded October 27, 2026; facts are paraphrased and counts and tables are Discovery Energy's own. The notices say the imbalance orders do not affect delivery of scheduled gas. No verbatim Transco text is used. Notice dates are posting dates. ↩
9. Transcontinental Gas Pipe Line Company, LLC, critical notices, location data and Index of Customers on the Williams 1Line site, public postings downloaded October 27, 2026; facts are paraphrased and counts and tables are Discovery Energy's own. The notices say the imbalance orders do not affect delivery of scheduled gas. No verbatim Transco text is used. Notice dates are posting dates. ↩
10. Transcontinental Gas Pipe Line Company, LLC, critical notices, location data and Index of Customers on the Williams 1Line site, public postings downloaded October 27, 2026; facts are paraphrased and counts and tables are Discovery Energy's own. The notices say the imbalance orders do not affect delivery of scheduled gas. No verbatim Transco text is used. Notice dates are posting dates. The alerts were posted on Transcontinental Gas Pipe Line Company, LLC, Operational Alert Notice 14227183, January 11, 2024; Transcontinental Gas Pipe Line Company, LLC, Operational Alert Notice 15220754, December 18, 2024; Transcontinental Gas Pipe Line Company, LLC, Operational Alert Notice 16336722, December 11, 2025; and Transcontinental Gas Pipe Line Company, LLC, Operational Alert Notice 16455061, January 15, 2026. ↩
11. Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012. ↩
12. Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012. ↩
13. NOAA Applied Climate Information System, monthly heating degree days base 65F and 1991-2020 normals for the Dover cooperative station (the Dover Air Force Base record has missing months) and the Salisbury-Wicomico Regional Airport station; computed. ↩
14. NOAA Applied Climate Information System, monthly heating degree days base 65F and 1991-2020 normals for the Dover cooperative station (the Dover Air Force Base record has missing months) and the Salisbury-Wicomico Regional Airport station; computed; Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012. ↩
15. NOAA Climate Prediction Center, official 90-day temperature outlook issued October 15, 2026 (GIS shapefiles; the favored category at the metro's principal county); the favored category's probability is NOAA's labelled value for the area, and the other two categories follow NOAA's published convention for the 3-class outlook maps, computed. []. ↩
16. Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012; Transcontinental Gas Pipe Line Company, LLC, critical notices, location data and Index of Customers on the Williams 1Line site, public postings downloaded October 27, 2026; facts are paraphrased and counts and tables are Discovery Energy's own. The notices say the imbalance orders do not affect delivery of scheduled gas. No verbatim Transco text is used. Notice dates are posting dates. ↩
17. Federal Energy Regulatory Commission orders and Eastern Shore Natural Gas Company and Chesapeake Utilities Corporation project pages, accessed October 27, 2026; sums computed. The Worcester Resiliency Upgrade status is not confirmed. ↩
18. U.S. Energy Information Administration, Form EIA-860M, September 2026 release, gas-fired units in the counties of the two metros, counted. ↩
19. Discovery Energy data center scan log, October 28, 2026; a search that finds nothing does not prove that no project exists. ↩
20. Delaware Public Service Commission, Order opening large load tariff docket for Delmarva, Docket 25-0826; Order No. 10816 (2025-09-03), Order, page 1, first WHEREAS clause. ↩
21. Columbia Gas Transmission, LLC, critical notices on TC eConnects, posted September 27, 2023 to October 27, 2026; market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers. Manual browser downloads, October 26 and 27, 2026. The operating area descriptions are dated December 14, 2012. Notice supporting the 24, 34 and 55 gas days in the Dover section: Columbia Gas Transmission, LLC, Capacity Constraint Notice 25980112, February 20, 2026. Notices for the force majeure events named in the Dover section: Columbia Gas Transmission, LLC, Force Majeure Notice 25887025, November 8, 2023 (Downingtown), and Columbia Gas Transmission, LLC, Force Majeure Notice 25926835, February 10, 2025 (Line 1804). ↩
22. NOAA Climate Prediction Center, official 90-day temperature outlook issued October 15, 2026 (GIS shapefiles; the favored category at the metro's principal county); the favored category's probability is NOAA's labelled value for the area, and the other two categories follow NOAA's published convention for the 3-class outlook maps, computed; NOAA Climate Prediction Center, official 90-day temperature outlook issued October 15, 2026 (GIS shapefiles; the favored category at the metro's principal county); the favored category's probability is NOAA's labelled value for the area, and the other two categories follow NOAA's published convention for the 3-class outlook maps, computed. []. The probabilities for Dover are 40.0% above normal, 33.3% near normal and 26.7% below normal for both November 2026 to January 2027 and December 2026 to February 2027. ↩
23. Chesapeake Utilities tariffs for Delaware (P.S.C. Del. No. 5) and Maryland, Delmarva Power order text (Delaware PSC docket 17-1013) and testimony in Delaware Public Service Commission docket 17-1021:. Utility statements and testimony are not commission findings; Federal Energy Regulatory Commission orders and Eastern Shore Natural Gas Company and Chesapeake Utilities Corporation project pages, accessed October 27, 2026; sums computed. The Worcester Resiliency Upgrade status is not confirmed. ↩
24. NOAA Climate Prediction Center, official 90-day temperature outlook issued October 15, 2026 (GIS shapefiles; the favored category at the metro's principal county); the favored category's probability is NOAA's labelled value for the area, and the other two categories follow NOAA's published convention for the 3-class outlook maps, computed; NOAA Climate Prediction Center, official 90-day temperature outlook issued October 15, 2026 (GIS shapefiles; the favored category at the metro's principal county); the favored category's probability is NOAA's labelled value for the area, and the other two categories follow NOAA's published convention for the 3-class outlook maps, computed. []. The probabilities for Salisbury are 40.0% above normal, 33.3% near normal and 26.7% below normal for both November 2026 to January 2027 and December 2026 to February 2027. ↩
25. Counts of distinct events by winter were made by Discovery Energy from Columbia's critical notices posted October 2023 to October 2026 (see note 2). ↩
26. Episodes of transport critical days that named Artemas East operating area, identified by Discovery Energy. Start and lift are the first and last gas days of the episode for the area (see note 7). ↩
27. Runs of imbalance operational flow order coverage and the days covered, counted by Discovery Energy from Transco notices posted October 2023 to March 2026. Some orders ended on a terminating notice and some are closed by the next order where the export holds no terminating notice (see note 8). ↩
28. Gas days with zero non-firm available capacity at Columbia constraints in the market areas that hold Dover's delivery points, by winter, with the denominator of parsed gas days; summer means June to August. Counted by Discovery Energy from Columbia Gas Transmission, LLC, Operationally Available Capacity postings, TC eConnects, accessed October 26, 2026; unparsed days are excluded (see note 12). ↩
29. Heating degree days, November to March, as a share of the 1991-2020 normal. Source: NOAA ACIS, computed (see note 13). ↩
30. Contracts listed under each shipper's name in Columbia Gas Transmission, LLC, Index of Customers, and Transcontinental Gas Pipe Line Company, LLC, Index of Customers, quarter beginning October 1, 2026, accessed October 27, 2026; Dth per day; tabulated by Discovery Energy (Columbia list regex-parsed, not hand-checked) (see note 16). ↩
31. Sources for Key takeaways item 5: Federal Energy Regulatory Commission, docket CP18-548, accessed October 27, 2026 (11,800 dts per day completed in September 2021); Eastern Shore, Southern Expansion project page, accessed October 27, 2026 (7,300 dts per day completed in October 2023). ↩
32. Transco locations list used for the matches: Transcontinental Gas Pipe Line Company, LLC, Index of Customers and location data, accessed October 27, 2026. ↩
33. Notice supporting the 24, 34 and 55 gas days in the section on distinct critical-day events: Columbia Gas Transmission, LLC, Capacity Constraint Notice 25980112, February 20, 2026. ↩
34. Force majeure notices: Transcontinental Gas Pipe Line Company, LLC, Force Majeure Notice 16347263, December 14, 2025 (Station 517), and Transcontinental Gas Pipe Line Company, LLC, Force Majeure Notice 16544208, February 8, 2026 (Station 115). ↩
35. Source for the Del-Mar Energy Pathway shipper shares of 7,750 Dth per day and 3,000 Dth per day: Federal Energy Regulatory Commission, docket CP18-548, accessed October 27, 2026. ↩
36. Source for the 2017 expansion of 61,162 Dth per day, including 10,000 Dth per day for Delmarva: Federal Energy Regulatory Commission, docket CP17-28, accessed October 27, 2026. ↩
37. The Downingtown event is covered by Columbia Gas Transmission, LLC, Force Majeure Notice 25887025, November 8, 2023, and Columbia Gas Transmission, LLC, Force Majeure Notice 25887710, November 16, 2023. The metros tied to these areas are Washington DC, Baltimore and Dover. ↩
38. The Line1804 event is covered by Columbia Gas Transmission, LLC, Force Majeure Notice 25926835, February 10, 2025, and Columbia Gas Transmission, LLC, Force Majeure Notice 25927826, February 16, 2025. The metros tied to these areas are Baltimore and Dover. ↩

Sources

1. Columbia Gas Transmission, LLC, critical notices, market area and operating area descriptions, locations report, daily capacity postings, unsubscribed capacity report and Index of Customers, TC eConnects, saved October 26 and 27, 2026.
2. Transcontinental Gas Pipe Line Company, LLC, critical notices, location data and Index of Customers, Williams 1Line information postings, accessed October 27, 2026. Link
3. Chesapeake Utilities Corporation, Delaware and Maryland gas tariffs; Eastern Shore project pages. Link
4. Delaware Public Service Commission, docket 17-1021 testimony and 2018 order text for Delmarva Power & Light Company.
5. Federal Energy Regulatory Commission, orders in dockets CP17-28 and CP18-548.
6. NOAA Applied Climate Information System, monthly heating degree days. Link
7. U.S. Energy Information Administration, Form EIA-860M, September 2026 release. Link
8. Office of Management and Budget, OMB Bulletin No. 23-01, Revised Delineations of Metropolitan Statistical Areas, Micropolitan Statistical Areas, and Combined Statistical Areas, July 21, 2023.
9. NOAA Climate Prediction Center, official 90-day temperature outlook, GIS data, issued October 15, 2026, saved October 28, 2026. Link
10. Data center scan records saved October 28, 2026 (AltaGas Ltd., Delaware and West Virginia agencies, Federal Register and others) are listed in the Notes.

Sources: Discovery Energy compilation from public FERC-required pipeline operational notices, capacity reports, and Indexes of Customers postings as published by the interstate pipelines serving this metro, and from public gas-utility documents. Discovery Energy is not affiliated with, endorsed by, or sponsored by any pipeline, utility, or regulator named on this page. All trademarks and names remain the property of their respective owners. Counts, summaries, tables, and charts are original Discovery Energy compilations; readers should verify against the cited notices. Data current as of October 27, 2026. For information only and not a guarantee of future pipeline operations, capacity, or pricing. - NOAA Climate Prediction Center, official 90-day temperature outlook, GIS data, issued October 15, 2026, saved October 28, 2026. https://www.cpc.ncep.noaa.gov/products/GIS/GIS_DATA/us_tempprcpfcst/seasonal.php - Data center scan records saved October 28, 2026 (AltaGas Ltd., Delaware and West Virginia agencies, Federal Register and others) are listed in the Notes.