Washington natural gas case study, Seattle, Washington. October 2026

Seattle and Olympia area natural gas capacity: no resource need until winter 2030-31, but Pierce and Thurston County area needs with no scheduled fix

PSE told the Washington Utilities and Transportation Commission (UTC) in its 2023 plan that it plans supply for a 13 degree design peak day and that its first resource need occurs in the winter of 2030-31 if existing pipeline contracts are renewed, after the three heating seasons this page covers. PSE said that without pipeline renewals the need would arise in the winter of 2025-26, and that its Northwest Pipeline contracts renew automatically and can be cancelled only by PSE on one year's notice. In its delivery system appendix PSE also lists a Bonney Lake area need in Pierce County, serving about 20,000 customers, where its high-pressure supply system falls below design requirements on a peak demand event; the pages read show no approved or scheduled fix. PSE lists a need with the same wording for the North Lacey area of Thurston County, in the Olympia metro, serving about 21,000 customers.

About 20,000 customersPSE's Bonney Lake area, Pierce County: supply system below design requirements on a peak day; no fix scheduled
About 21,000 customersPSE's North Lacey area, Thurston County: same need and status as Bonney Lake; no fix scheduled
13 degreesPSE's design peak day (52 heating degree days), whole system, per PSE's plan
Winter 2030-31PSE's first projected resource need if pipeline contracts are renewed, whole system, per PSE

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

Key takeaways

  • PSE said in its 2023 plan that it plans supply to meet firm loads on a 13 degree design peak day, a 52 heating degree day, and forecast base peak-day demand of 995 thousand Dth for 2024 and 1,043 thousand for 2030 for its whole system.2
  • PSE said in the same plan that the first resource need in its mid demand forecast occurs in the winter of 2030-31 if existing pipeline contracts are renewed, and in the winter of 2025-26 if no pipeline renewals are assumed; both are whole-system statements.3
  • PSE's delivery system appendix lists three area needs in the counties of the two metros with no approved or scheduled fix: the Bonney Lake area in Pierce County (about 20,000 customers) and the North Lacey area in Thurston County (about 21,000 customers), where PSE said its high-pressure supply systems fall below design requirements on a peak demand event, and the marine crossing serving the Gig Harbor peninsula and Vashon/Maury Island (about 13,000 customers), its only gas pipeline supply.12
  • PSE said Northwest Pipeline is its only direct-connect pipeline, and its table shows total firm capacity to the city gate of 989,929 Dth per day as of November 2020, made up of 542,872 Dth per day of year-round transportation and 447,057 Dth per day of storage redelivery.4
  • PSE said its Northwest Pipeline contracts have automatic annual renewal provisions that PSE can cancel on one year's notice, and its preferred portfolio shows 59 thousand Dth per day of pipeline renewals not made in 2024, rising to 142 thousand by 2030, which PSE ties to lower demand and other resources.45
  • System context: PSE said Woodfibre LNG in British Columbia will pull 300 thousand Dth per day out of the Sumas market hub, and that there is growing concern over uncommitted gas at Sumas when Woodfibre starts up in 2027.6
  • A search of official records found no planned natural gas-fired generator in King, Pierce or Snohomish County in EIA's September 2026 inventory, and no pipeline notice naming those counties among Federal Energy Regulatory Commission notices since January 1, 2025.8

Which parts of the record fall inside the Seattle metro?

System context: PSE's plan covers its whole gas system. PSE said its gas service territory includes parts of King (not Enumclaw), Kittitas (not Ellensburg), Lewis, Pierce, Snohomish and Thurston counties, so parts of the three Seattle metro counties and of Thurston County, the Olympia metro's one county, are inside the two metros, and Kittitas and Lewis counties are outside both.1

Where Item in PSE's plan
Inside the Seattle metro Parts of King, Pierce and Snohomish counties in PSE's gas territory; the Bonney Lake study area (Pierce County); the marine crossing serving the Gig Harbor peninsula (Pierce County) and Vashon/Maury Island (King County)
Inside the Olympia-Lacey-Tumwater metro The part of Thurston County in PSE's gas territory; the North Lacey study area (Lacey and the north and east Olympia areas)
Outside both metros, system context Kittitas and Lewis counties in PSE's gas territory; PSE's system-wide peak day, resource need and pipeline capacity; Woodfibre LNG and the Sumas hub in British Columbia
Unclear Other gas utilities in the metro counties; the town-level split of PSE's territory

PSE's gas territory and system-wide figures, by whether they fall inside the Seattle or Olympia metro (OMB delineation). Source: 2023 Gas Utility Integrated Resource Plan, About PSE, Chapter Six and Appendix G.112

System context: the plan gives no peak-day figure for King, Pierce, Snohomish or Thurston County alone, so the system-wide figures are the most local the record has for supply and the design day. For the delivery system it does name area needs, and those are the most local figures the record has; they are set out in the next section.

What local needs does PSE's delivery system plan show?

PSE's delivery system planning appendix lists three projects in the initiation phase, each with a date needed of "Existing" or "Current", and says it has no major backbone projects in the implementation phase. It describes the end of the initiation phase as the point where senior management approves a project for funding.12 Two of the three are in the Seattle metro's counties; the third, North Lacey, is in the Olympia metro and has its own section below.

Area County Customers Need date What PSE said Fix in the pages read
Bonney Lake Reinforcement (Lake Tapps and South Prairie) Pierce About 20,000 Existing; identified 2008 The high-pressure supply system is undersized and falls below design requirements on a peak demand event for existing loads; three cold weather actions are scheduled along with 100 percent curtailments Neither approved nor scheduled: study of pipeline and non-pipe solutions expected to finish in early 2023; no solution, date or budget
Gas Reliability Marine Crossing King (Vashon/Maury Island) and, by general geography, Pierce (Gig Harbor peninsula) About 13,000 Current; identified 2018 The crossing is the only gas pipeline supply to the area and is nearing the end of its service life; the supply system cannot meet minimum design requirements should the lateral exceed its fatigue limits Neither: an emergency backup supply plan was to be enabled in 2023; no long-term solution, date or budget

Local needs in PSE's 2023 delivery system plan, metro counties, by fix status under Outlook Scale v2.3 (approved: a regulator has approved it; scheduled: in the filed plan with a date and a budget; neither). Source: Appendix G, sections 3.4.1 and 3.4.3.12

PSE said the cold weather actions it has scheduled for Bonney Lake, along with 100 percent curtailments, are markedly insufficient to address the reliability concerns. The plan does not say which customers would be curtailed, so this page does not treat it as a curtailment of firm customers. The marine crossing item is a condition, a lateral exceeding its fatigue limits, and not a projected shortfall, and PSE's Gig Harbor LNG facility supplements supply to the area at peak.12

The appendix is part of the 2023 plan, which PSE's Integrated System Plan due January 1, 2027 replaces. A scripted search for any approval, date or budget for these projects after March 2023 found none (note 13); a later approval or budget would change the fix status.12

What does PSE's plan show for Olympia-Lacey-Tumwater?

The Olympia-Lacey-Tumwater metro is Thurston County, which is inside PSE's gas territory. PSE's delivery system appendix lists the North Lacey Reinforcement there, covering Lacey and the north and east Olympia areas and about 21,000 customers, with a date needed of "Existing" and a need identified in 2009; PSE said the current high-pressure supply system is undersized and falls below current design requirements during a peak demand event for existing gas loads.12

Area County Customers Need date What PSE said Fix in the pages read
North Lacey Reinforcement (Lacey and the north and east Olympia areas) Thurston About 21,000 Existing; identified 2009 The high-pressure supply system is undersized and falls below design requirements on a peak demand event for existing loads; two cold weather actions are scheduled along with 100 percent curtailments Neither approved nor scheduled: detailed needs assessment and alternatives review expected in 2023; no solution, date or budget

Local need in PSE's 2023 delivery system plan, Olympia-Lacey-Tumwater metro, by fix status under Outlook Scale v2.3. Source: Appendix G, section 3.4.2.12

PSE said the two cold weather actions scheduled for North Lacey, along with 100 percent curtailments, are markedly insufficient; the plan does not say which customers would be curtailed, so this page does not treat it as a curtailment of firm customers.12 PSE said it expected to complete the detailed needs assessment and alternatives review in 2023, and the pages read give no selected solution, date or budget.12 PSE's supply figures remain for its whole system, so the system-wide statements on this page apply to both metros only as system context. The need has the same wording, utility, record and status as Bonney Lake, so the Olympia-Lacey-Tumwater metro is rated with the Seattle area.

How much spare gas capacity does Seattle have on the coldest day?

Major natural gas pipelines serving Seattle N Northwest Pipeline Northwest Pipeline Other transmission pipelines in the EIA layer (interstate and intrastate; unlabeled) Pipeline named in a verified claim on this page (labeled, one color each) Metro counties (boundary used on this page) Major highways (for orientation)
Figure 1. Major natural gas pipelines serving Seattle. Simplified, not to scale. Discovery Energy illustration from EIA and U.S. Census data. Coastline, lakes and highways: Natural Earth (public domain).

PSE said it plans supply to meet firm loads on a 13 degree design peak day. For its whole system PSE's base forecast puts peak-day demand at 995 thousand Dth in 2024 and 1,043 thousand in 2030.2

PSE reported the capacity it holds with Northwest Pipeline, its only direct-connect pipeline, as of November 2020.4

Firm capacity to PSE's city gate Dth per day
Northwest Pipeline TF-1, from the Westcoast interconnect at Sumas 287,237
Total year-round TF-1 transportation 542,872
Storage redelivery from Jackson Prairie 447,057
Total firm capacity to the city gate 989,929

PSE's firm pipeline capacity as of November 2020, whole system, Dth per day, per PSE. Source: 2023 Gas Utility Integrated Resource Plan, Appendix E, Table E.1.4

PSE said that in its zero-growth demand forecast it has sufficient firm resources to meet peak day need throughout the study period if it automatically renews existing pipeline contracts, and that in the mid demand forecast the first resource need occurs in the winter of 2030-31 on the same assumption. Without pipeline renewals, PSE said, the need arises in the winter of 2025-26.3

PSE's resource figures are shown in charts, and the plan's text does not total its on-system peaking capacity against the design day, so the record read does not show a reserve margin for the coldest day. That is not established here and is not estimated.

What is driving new natural gas demand?

PSE's plan forecasts demand for its whole system from customer counts and weather and does not name a large new gas load inside the three counties. System context: PSE said Woodfibre LNG, an export project in British Columbia, will pull 300 thousand Dth per day out of the Sumas market hub using previously acquired firm capacity, and that there is growing concern over the availability of uncommitted gas at Sumas when Woodfibre starts up in 2027; PSE sources part of its supply at Sumas.6

A search of other official records found no further documented gas load in the three metro counties: EIA's September 2026 generator inventory lists no planned natural gas-fired generator there, and a search of Federal Register notices of the Federal Energy Regulatory Commission since January 1, 2025 found no pipeline notice naming any of the three counties.8

Are upgrades arriving in time?

For the supply plan, PSE's plan does not show a resource need inside the three heating seasons this page covers, and PSE said it is not studying pipeline expansion projects in its 2023 plan because, among other reasons, it has sufficient capacity on the Northwest and Westcoast pipelines.7 For the local delivery needs above, the record read shows no fix that is approved or scheduled: PSE's projects for Bonney Lake, North Lacey and the marine crossing are in the initiation phase, with no funding approval, date or budget in the pages read.12

For the resource plan, PSE's near-term priorities (2024 to 2029) include acquiring Plymouth liquefied natural gas capacity rights and 15 thousand Dth per day of deliverability on Northwest Pipeline, and its long-term priorities (2030 to 2050) include reducing transport pipeline capacity contracts when the gas sales portfolio becomes surplus from decreasing loads.5

The UTC docket for the plan, UG-220242, shows an open meeting on June 26, 2023 and does not show a Commission approval of the plan.9

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, among other areas, the northern tier from the Pacific Northwest eastward, a discussion that names regions and not counties, and that the probability of at least a strong El Nino continuing through January to March 2027 is 80%.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 Seattle gas capacity through 2029?

Discovery Energy rates the outlook for natural gas capacity in the Seattle area and the Olympia-Lacey-Tumwater area through 2029 as Elevated (confidence: High): PSE's own delivery system plan says its high-pressure supply systems in the Bonney Lake area of Pierce County and the North Lacey area of Thurston County fall below design requirements on a peak demand event for existing loads, and the pages read show no approved or scheduled fix for either; the rating rests on these area records inside each metro; the system-wide supply plan shows no resource need before the winter of 2030-31 if pipeline contracts are renewed, a figure for the whole system. Documented risk factors: none beyond the base level. Three developments would change the assessment: PSE's Integrated System Plan due January 1, 2027, which replaces the 2023 gas plan, with any approved or scheduled fix, with a date and a budget, for the Bonney Lake, North Lacey and marine crossing needs, and any new resource need date or decision to let pipeline contracts expire; PSE's renewal decisions for Northwest Pipeline capacity, including the November 2028 renewal offered for part of its Sumas capacity; Woodfibre LNG's start-up in 2027 and the supply available at the Sumas hub.

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 Seattle-area 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.
  • Which service. Confirm whether each site takes firm or interruptible service from PSE, and read the interruption terms in the current approved tariff.
  • Your area. If a site is in the Bonney Lake, Lake Tapps or South Prairie area of Pierce County, in the Lacey or north or east Olympia area of Thurston County, or on the Gig Harbor peninsula or Vashon/Maury Island, ask PSE about the status of the local reinforcement and its cold weather action plans.
  • 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 proceedings. Track PSE's Integrated System Plan due January 1, 2027, and any notice about its pipeline contract renewals.

Frequently asked questions

Will Seattle businesses face natural gas shortages this winter?

The record does not show a shortage. PSE said in its 2023 plan that its first resource need occurs in the winter of 2030-31 if its pipeline contracts are renewed, a statement for its whole system. For the Bonney Lake area of Pierce County PSE said its high-pressure supply system falls below design requirements on a peak demand event, and that cold weather actions with 100 percent curtailments are scheduled; it did not say which customers. This page makes no prediction about outages.

Does Puget Sound Energy have spare gas capacity on the coldest day?

PSE plans supply for a 13 degree design peak day and showed total firm capacity to its city gate of 989,929 Dth per day as of November 2020 against a base forecast of 995 thousand Dth of peak-day demand in 2024. The plan's text does not total its peaking resources, so the record read does not show a reserve margin.

What would happen if PSE did not renew its pipeline contracts?

PSE said that if no pipeline renewals are assumed, its need arises in the winter of 2025-26. Its Northwest Pipeline contracts renew automatically and PSE can cancel them on one year's notice.

Did the Washington UTC approve PSE's gas plan?

The UTC docket UG-220242 shows an open meeting on June 26, 2023 and does not show an approval. PSE's Integrated System Plan due January 1, 2027 replaces the gas plan.

Is a data center or power plant driving gas demand in Seattle?

The record does not show one. PSE's plan names no large new gas load inside the three counties, EIA's September 2026 inventory lists no planned gas-fired generator there, and no Federal Energy Regulatory Commission pipeline notice names them. PSE did say Woodfibre LNG in British Columbia will draw on the Sumas hub from 2027.

Are there local gas capacity needs in the Seattle and Olympia areas?

PSE's 2023 delivery system plan lists the Bonney Lake area in Pierce County (about 20,000 customers; high-pressure supply system below design requirements on a peak demand event), the marine crossing serving the Gig Harbor peninsula and Vashon/Maury Island (about 13,000 customers; its only gas pipeline supply) and the North Lacey area in Thurston County, in the Olympia metro (about 21,000 customers; the same wording as Bonney Lake) as needs with no approved or scheduled fix in the pages read. It did not say which customers would be curtailed. Ask PSE for the current status.

Related case studies

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

All gas capacity ratings by U.S. metro

Understand your capacity exposure

Discovery Energy reviews service elections, interruption terms and regulatory proceedings for organizations across the U.S. and Canada, so capacity changes are understood before they reach the bill.

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Notes

  1. Puget Sound Energy, 2023 Gas Utility Integrated Resource Plan, Chapter Book, PDF 3 (About PSE); Washington UTC docket UG-220242. Utility statement. Metro counties from metro_counties.csv; classification in seattle_metro_classification.csv. [SEA-01] ↩
  2. Same plan, Chapter Six, PDF 107 (design peak day) and Chapter Five, PDF 85 (Table 5.5, base forecast). Utility statements. [SEA-03, SEA-04] ↩
  3. Same plan, Chapter Six, PDF 107 and PDF 108. [SEA-05 to SEA-07] ↩
  4. Same plan, Appendix Book, Appendix E, PDF 177 to 181 (Tables E.1 and E.2 and notes), capacity as of November 1, 2020. Shares run by code and not used in the text (seattle_calculations.csv; illustrative): the TF-1 capacity in the table column headed 2023-2028 is 18.85% of the 2024 base design day and 18.95% of total firm capacity to the city gate. [SEA-08 to SEA-13] ↩
  5. Same plan, Chapter One, PDF 18 (Table 1.1) and Chapter Two, PDF 22. [SEA-14 to SEA-16] ↩
  6. Same plan, Chapter Six, PDF 111. [SEA-18, SEA-19] ↩
  7. Same plan, Chapter Six, PDF 107 (recommendations). [SEA-17] ↩
  8. EIA-860M inventory for September 2026 (Planned sheet, operator-reported planned dates), filtered to King, Pierce and Snohomish counties by code, and a Federal Register search of FERC notices since January 1, 2025 by county phrase, both computed by code. A notice that spells a place differently would be missed. [SEA-22, SEA-23] ↩
  9. Washington Utilities and Transportation Commission, docket UG-220242 document list, saved October 25, 2026. [SEA-02] ↩
  10. Not established, and left out of the page: supply events since January 1, 2020 affecting PSE in an official record (PSE's plan describes a 2018 Westcoast rupture and a February 2019 storage compressor failure, both before the window; news reports of a January 2024 conservation request were found but are leads only and were not confirmed in an official record); delivery-point utilization from pipeline postings (Northwest Pipeline's postings were not captured; next capture about March 2027); PSE's cost allocation among customer classes and its interruption sequence (the gas tariff was not read); whether Cascade Natural Gas or another utility serves part of the metro; and the meaning of the column headings 2023-2028 and 2028+ in Table E.1 (the table text does not say whether they mark contract expiry).
  11. R3 not established, and left out of the claims (searches run: EIA-860M, a Federal Register search of FERC notices by county, and the plan text): state air permit records (Washington Department of Ecology, Puget Sound Clean Air Agency), Northwest Pipeline or PSE interconnection queues and FERC eLibrary filings, none of which a script could save; news reports are leads only and are not claimed.
  12. Same plan, Appendix Book, Appendix G (Delivery System Planning): section 2.3, PDF 248; section 3.2.5, PDF 253; sections 3.4.1 to 3.4.3 and Table G.3, PDF 254 to 257. Utility statements as of March 2023. The county placement of Bonney Lake and the Gig Harbor peninsula, and of Lacey and Olympia, is general geography, not a quotation. Their status after March 2023 was searched by script (note 13). [SEA-N01 to SEA-N18] ↩
  13. Scripted search on October 26, 2026 for any approval, date or budget for these projects after March 2023: the pages of UTC dockets UG-230807, UG-220242 and PG-170423, PSE's 2023 IRP, IRP, projects and pending filings pages, and 348 PDFs listed on the UTC docket pages (the eight UG-230807 filings and 340 PSE testimony and exhibit files of 25 MB or less in PSE's 2024 general rate case, UG-240005), for the terms Bonney Lake, Lake Tapps and South Prairie. It found no funded fix, date or budget (four hits in the PDFs: an electric submarine cable table and three map labels). It did not search larger files, other dockets or PSE's capital budget documents, and the Integrated System Plan is not yet filed. Record: batches/SEA-CHECK/bonney_lake_check.md.

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. Puget Sound Energy, 2023 Gas Utility Integrated Resource Plan, Chapter Book. Link
  2. Puget Sound Energy, 2023 Gas Utility Integrated Resource Plan, Appendix Book. Link
  3. Washington Utilities and Transportation Commission, docket UG-220242 (Puget Sound Energy's 2023 Gas Integrated Resource Plan). Link
  4. 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.
  5. U.S. Energy Information Administration, EIA-860M Preliminary Monthly Electric Generator Inventory, September 2026. Link
  6. Federal Register, API search of Federal Energy Regulatory Commission notices by county. Link