South-central Pennsylvania natural gas capacity: Harrisburg, Lancaster and Reading, one thin peak-day margin and one unfilled supply line

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

Key takeaways

Which parts of the record fall inside the three metros?

UGI Gas's tariff lists 46 counties. Four of the five counties in the three metros, Cumberland and Dauphin (Harrisburg-Carlisle), Lancaster (Lancaster) and Berks (Reading), are among them; Perry County, the third county of the Harrisburg-Carlisle metro, is not, so the record does not identify the serving utility for Perry County.⁵

UGI Gas's tariff territory, by whether each county is in one of the three metros (OMB delineation). Source: UGI Gas tariff, Pa. P.U.C. No. 7, Description of Territory.⁵

System context: every capacity figure on this page is UGI Gas-wide. The record does not allocate any of it to a county or a metro, so the same figures apply to all three metros and no metro has a figure of its own.

Harrisburg-Carlisle (Cumberland, Dauphin and Perry counties; population 617,427 in 2025⁶). UGI Gas's tariff lists the City of Harrisburg and many Dauphin County boroughs and townships, and Camp Hill, Carlisle, Lemoyne, Mechanicsburg and other Cumberland County boroughs and townships. Perry County is not listed.⁵

Lancaster (Lancaster County; population 563,159 in 2025⁶). UGI Gas's tariff lists Lancaster County, including the City of Lancaster and boroughs such as Columbia, Elizabethtown, Ephrata, Lititz, Manheim and Mount Joy, and many townships. The filings reviewed do not say whether another gas utility serves part of the county.⁵

Reading (Berks County; population 440,072 in 2025⁶). UGI Gas's tariff lists Berks County, including the City of Reading and boroughs such as Birdsboro, Boyertown, Hamburg, Kutztown, Shillington and Wyomissing, and many townships. The filings reviewed do not say whether another gas utility serves part of the county.⁵

The three metros together have a population of 1,620,658⁶. No large load, data center, local station or local capacity project in any of the three metros is documented in the UGI Gas books reviewed, so none is claimed for any metro here.

How much spare gas capacity does south-central Pennsylvania have on the coldest day?

UGI Gas said its distribution systems are fed directly by nine interstate pipelines, including Tennessee Gas Pipeline, Columbia Gas Transmission, Transcontinental Gas Pipe Line Company (Transco), Texas Eastern and Eastern Gas Transmission and Storage; some systems are fed by several pipelines and others are isolated feeds, and the filing does not say which pipeline serves which county.¹³

UGI Gas's schedule, headed "Peak Day Capacity Requirements and Supply Options" for the year ending September 30, 2027, is in dekatherms (Dth).¹

UGI Gas's peak-day capacity and requirements for the year ending September 2027, system-wide, from its January 2026 data request response. The last two rows are our subtraction.¹²

The Outlook Scale treats a projected reserve below 5% of design day as a thin margin; both figures above are below it. The schedule shows no negative balance, no need date and no project. Peaking services from UGI Energy Services, 479,187 Dth, are the largest single line.³

UGI Gas's annual peak-day sendout, interruptible service included, was 1,648.9 MDth in February 2023, 1,705.6 MDth in January 2024 and 1,694.6 MDth in February 2025. The Reading, Harrisburg, Lehigh, Lancaster and Altoona area temperature on those days was 16, 18 and 20 degrees Fahrenheit. These are actual sendout days, a different measure from the 2026-27 requirements schedule, and the record does not compare them.⁴

What is driving new natural gas demand?

The UGI Gas books reviewed document no data center, gas-fired generator or other new large load in the three metros. A search of other official records found none either: EIA's September 2026 generator inventory lists no planned natural gas-fired generator in Dauphin, Cumberland, Perry, Lancaster or Berks county, and PJM's Transition Cycle 1 Phase III list shows eight Pennsylvania projects, all solar or solar with storage.¹¹ The search did not find a FERC pipeline filing for a new delivery point or lateral in these counties; its limits are in Note 12.

What does this mean for business gas costs?

On October 1, 2026 the Commission adopted, without modification, the settlement of UGI Gas's base rate case, which allows $65 million in base rate increases in two steps: $40 million from October 1, 2026 and $25 million from October 1, 2027. The settlement bars UGI Gas from filing a general rate increase on or before January 15, 2029.⁹

Whole system, step one only: step-one revenue change by rate class as settled, UGI Gas-wide (Settlement Appendix B, proof of revenue). The second step's class split is not summarized here.⁸

This is the whole-system class allocation of a revenue increase. The record does not show how the capacity items above are costed by class, or any dollar effect on a customer in the three metros.⁸

Who gets gas first in a shortage?

UGI Gas's tariff Rule 21 says that, if time permits, before curtailing customers the company will use reasonable efforts to interrupt all interruptible services, issue operational flow orders or daily flow directives, and call for voluntary usage reductions. If it then mandates reductions on commercial and industrial customers that are not Priority 1, the reduction is "determined by the Company without regard to priorities of use", lasts at most five consecutive business days unless the Commission extends it, and may not go below the minimum usage for plant protection except when Priority 1 service itself cannot be met.¹⁰

Winter and market context

Context only, as of October 2026. It does not set the outlook level and makes no prediction of outages. Its sources are listed separately under Market and weather sources and are refreshed on the publication date.

NOAA's Climate Prediction Center said on October 15, 2026 that its November 2026 to January 2027 temperature outlook favors above-normal temperatures for regions it calls the Ohio Valley and mid-Atlantic, and that the probability of at least a strong El Niño continuing through January to March 2027 is 80%; its discussion names regions, not Pennsylvania counties.^B1 The U.S. Energy Information Administration (EIA) said on October 6, 2026 that it expects U.S. natural gas inventories to enter the winter heating season 2% above the previous five-year average, and that prolonged periods of cold weather could increase withdrawals beyond its forecast.^A1A2 EIA lists U.S. liquefied natural gas gross exports of 15 billion cubic feet per day in 2025, 18 in 2026 and 19 in 2027.^A1 These are national and regional facts, not statements about the utility's system, and none of them is used to set the outlook on this page.

What is the outlook for south-central Pennsylvania gas capacity through 2029?

Discovery Energy rates the outlook for south-central Pennsylvania natural gas capacity (the Harrisburg-Carlisle, Lancaster and Reading metros) through 2029 as Elevated (confidence: Medium): UGI Gas's own 2026-27 peak-day schedule shows a margin of about 2.6%, or about 1.3% without a supply line labeled "Supply TBD" that the record does not show as contracted, and the record shows no approved or scheduled fix; it also shows no negative balance or need date, and every figure is system-wide. Documented risk factors: concentration (F1), since UGI Energy Services peaking services are 21.0% of 2026-27 peak-day requirements, a Discovery Energy calculation from UGI Gas's figures (479,187 ÷ 2,280,283); one factor does not raise the level. Three developments would change the assessment: UGI Gas's next peak-day schedule, including whether the 30,436 Dth "Supply TBD" line is contracted or identified and what the margin is, or any approved or scheduled capacity addition; any change in UGI Gas's reliance on peaking services from UGI Energy Services; a capacity filing, or a rate case after the January 15, 2029 stay-out date, that shows a negative balance.

Outlook levels, from least to most concern: Stable, Watch, Elevated, High, Severe. Levels describe the public record of capacity and supply risk; confidence is reported separately. They are qualitative assessments, not forecasts of outages.

What should south-central Pennsylvania facilities 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.
• Rate class and utility. Confirm each site's UGI Gas rate class (for example N/NT, DS, LFD, XD or interruptible) and, for Perry County sites, the serving utility.
• Firm or interruptible, and the terms. Know whether each account is firm or interruptible and the flow-order, reduction and plant-protection terms in Rule 21 before the first cold snap.
• 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.
• Settlement step two. The second step of the base rate increase takes effect on October 1, 2027.

Frequently asked questions

Related case studies

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

• Pittsburgh natural gas capacity case study (outlook: High)
• York natural gas capacity case study (outlook: Elevated)
• Albany natural gas capacity case study (outlook: Elevated)
• Buffalo natural gas capacity case study (outlook: Elevated)

Notes

1. UGI Utilities, Inc. - Gas Division, Docket R-2025-3059523, Book II, response to SDR-COS-10, Attachment SDR-COS-10 page 5 of 5 (PDF 22), delivered January 28, 2026; utility filing, system-wide, quantities in Dth. [SCP-01 to SCP-07] ↩
2. Same attachment. 2,340,671 minus 2,280,283 is 60,388 Dth, or 2.65% of requirements; excluding the 30,436 Dth "Supply TBD" line, 29,952 Dth, or 1.31%. Illustrative, run by code (harrisburg_calculations.csv). The record does not say whether the "Supply TBD" line is contracted. [SCP-03] ↩
3. Same attachment: UGI Energy Services Peaking Services 479,187 Dth, 21.0% of 2,280,283; third-party capacity for large customers 848,207 Dth, 37.2%; illustrative. The share is a Discovery Energy calculation from UGI Gas's figures: 479,187 ÷ 2,280,283 = 21.0%. [SCP-04, SCP-05] ↩
4. Attachment SDR-COS-10 page 1 of 5 (PDF 18): peak-day sendout by rate class and temperature by area. [SCP-08, SCP-09] ↩
5. UGI Gas tariff, Pa. P.U.C. No. 7, Supplement No. 59 (Book X), Description of Territory (PDF 9 to 24): 46 county headings counted by code, 4 in the three metros, 42 outside; Perry County has no heading (south_central_pa_metro_classification.csv). County boundaries from OMB Bulletin No. 23-01 (delineation file list1_2023.xlsx). [SCP-13, SCP-14, SCP-23, SCP-24] ↩
6. U.S. Census Bureau, Annual Resident Population Estimates for Metropolitan Statistical Areas, Vintage 2025 (July 1, 2025): Harrisburg-Carlisle 617,427; Lancaster 563,159; Reading 440,072; total 1,620,658 by code. ↩
7. Not established, and left out of the page: whether another gas utility serves part of Lancaster County or Berks County (only UGI Gas's filings were reviewed); local stations, local capacity and local large loads in the three metros; supply events since 2020 affecting UGI Gas (the filings give annual peak days only); new large loads or data centers (none found in the UGI books reviewed, which were Books I, II, III, V, VI, IX and X); capacity remedies and projects (none found); contract end dates (attachment SDR-COS-14 not read); delivery-point utilization from pipeline postings (the pipelines' posting sites could not be read by script); the previous design-day standard.
8. Joint Petition for Approval of Settlement of All Issues, filed July 6, 2026, paragraph 35 (PDF 14) and Appendix B, Proof of Revenue Summary, page 1 of 7 (PDF 123). Settlement among UGI Gas, the Office of Consumer Advocate, the Office of Small Business Advocate, the Bureau of Investigation and Enforcement and the Retail Energy Supply Association. [SCP-15 to SCP-19, SCP-21, SCP-22] ↩
9. Commission Opinion and Order, adopted and entered October 1, 2026, ordering paragraph 1 (the Commission adopted the Initial Decision of the administrative law judges dated July 31, 2026). [SCP-20] ↩
10. UGI Gas tariff, Pa. P.U.C. No. 7, Rule 21, Gas Emergency Planning, Supplement No. 59 as filed (Book X PDF 77 to 78). [SCP-10 to SCP-12] ↩
11. EIA-860M inventory for September 2026 (Planned sheet, operator-reported planned dates), filtered to Dauphin, Cumberland, Perry, Lancaster and Berks counties by code, and the PJM Transition Cycle 1 Phase III project list (Pennsylvania rows; the list has no county column), both computed by code (south_central_pa_calculations.csv). [SCP-25, SCP-26] ↩
12. R3 not established (searches run: EIA-860M, PJM Transition Cycle 1, Federal Register FERC notices, DEP and Pennsylvania Bulletin web searches): any state air plan approval, PJM Cycle 1 (2026) queue entry or FERC filing for a gas-fired plant, data center or new pipeline delivery point in the five counties was not found; PJM's Cycle 1 applications by county are not published in a form code could save, and Pennsylvania Bulletin notices do not allow scripted access. A Pennsylvania Bulletin notice for an 8-inch UGI Utilities pipeline in Lower Paxton Township (Dauphin County) was seen only in a blog digest and is a distribution pipeline notice, not a documented load. Manual downloads are listed in batches/PJM-01/tara_review_addendum.md.
13. UGI Utilities, Inc. - Gas Division, Docket R-2025-3059523, Book I, response to I-C-1 part a. (PDF 62), delivered January 28, 2026; utility filing, system-wide. The same sentence also names UGI Sunbury, UGI Mt. Bethel Pipeline, Adelphia Gateway and UGI Storage, which the map does not draw. [SCP-33 to SCP-37] ↩

Market and weather sources

Public web sources saved and hashed on October 25, 2026. They are context, separate from the regulatory record cited in the Notes. The Climate Prediction Center issues its seasonal outlook once each month near mid-month; this section is refreshed on the publication date.

1. A1. U.S. Energy Information Administration, press release, "EIA expects a mixed picture for winter fuel costs this year," October 6, 2026. Link ↩
2. A2. U.S. Energy Information Administration, Short-Term Energy Outlook, October 2026 (natural gas storage). Link ↩
3. B1. NOAA Climate Prediction Center, Prognostic Discussion for Long-Lead Seasonal Outlooks, issued October 15, 2026. Link ↩

Sources

1. Pennsylvania Public Utility Commission, docket R-2025-3059523, UGI Utilities, Inc. - Gas Division base rate case: Book I, filing requirement responses (valuation). Link
2. Pennsylvania Public Utility Commission, docket R-2025-3059523, UGI Utilities, Inc. - Gas Division base rate case: Book II, standard data request responses. Link
3. Pennsylvania Public Utility Commission, docket R-2025-3059523: Book X, tariff Pa. P.U.C. No. 7, Supplement No. 59. Link
4. Pennsylvania Public Utility Commission, docket R-2025-3059523: Joint Petition for Approval of Settlement of All Issues. Link
5. Pennsylvania Public Utility Commission, docket R-2025-3059523: Commission Opinion and Order. Link
6. Pennsylvania Public Utility Commission, docket page for R-2025-3059523. Link
7. 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.
8. U.S. Census Bureau, Annual Resident Population Estimates for Metropolitan Statistical Areas, Vintage 2025.
9. U.S. Energy Information Administration, EIA-860M Preliminary Monthly Electric Generator Inventory, September 2026. Link
10. PJM Interconnection, Transition Cycle 1 Phase III Executive Summary. Link