What are PG&E Citygate and Sumas?

curl -H "Authorization: Token YOUR_KEY" \
  "https://api.oilpriceapi.com/v1/prices/past_year?by_code=NATURAL_GAS_PGE_CITYGATE_USD&interval=daily"

Where is PG&E Citygate?

It is not one physical place. PG&E describes the Citygate as a virtual trading point on its California Gas Transmission system, at any point where the backbone transmission system connects to the local transmission and distribution system. Gas reaches the backbone along two paths: the Redwood path, which starts at Malin or Onyx Hill, and the Baja path, which starts at Kern River Station, the High Desert Lateral, Daggett, Southern Trails or Topock (PG&E). PG&E's own storage and third-party on-system storage also sit at the Citygate.

Because the Citygate is downstream of those receipt points, its price includes the cost of moving gas across the backbone. Malin, Oregon, where the Redwood path can start, is a separate pricing point, and EIA reports it alongside PG&E Citygate.

Where is Sumas?

EIA calls Northwest Sumas the key pricing hub along the British Columbia–Washington border for natural gas in the Pacific Northwest. On the Canadian side, Enbridge's Westcoast system (the BC Pipeline), 3,152 km long and operating since 1957, carries gas from the Western Canadian Sedimentary Basin south to the border. At Huntingdon it connects to FortisBC for the Vancouver area and to the Williams Northwest pipeline for export to the United States; the CER puts capacity at Huntingdon/FortisBC Lower Mainland at about 1.7 Bcf/d.

EIA notes that Sumas gives Pacific Northwest buyers supply diversity and lists the regional conditions its price reflects: the state of the hydroelectric market, natural gas storage availability, space heating needs, upstream gas conditions in British Columbia, and increasing use of gas for power generation.

Why do West Coast hubs spike above Henry Hub?

EIA notes that the western region receives most of its natural gas supply from other parts of the United States and Canada. When a supply pipeline is constrained, storage is low and temperatures drop at the same time, the local price has to rise until demand falls. EIA has documented two episodes that show the mechanism.

Sumas, March 2019: a pipeline rupture and a cold snap

Sumas averaged $161.33/MMBtu on Friday, 1 March 2019, the highest price in at least five years (EIA). Four things lined up:

• An October 2018 explosion on Enbridge's BC Pipeline had reduced flows through British Columbia into Washington.
• Compression problems at the Jackson Prairie storage facility cut its withdrawal capacity from 690 MMcf/d to 460 MMcf/d from around 9 February.
• Washington averaged 33°F from 1 to 4 March, 10°F below normal.
• BC Pipeline inspections were scheduled from 27 February to 6 March.

EIA reported that prices reached roughly ten times the previous week's level, then fell back once the inspections ended and temperatures rose.

The West, December 2022: prices above $50

On 21 December 2022, PG&E Citygate, Northwest Sumas and Malin all traded above $50.00/MMBtu, an average of $48.12 above Henry Hub. EIA said PG&E Citygate and Malin reached their highest prices since December 2000 in both real and nominal terms.

EIA tied the spike to below-normal temperatures across the West, high consumption, lower imports from Canada, pipeline constraints including maintenance in West Texas, and Pacific region storage that was 30% below its five-year average as of 16 December. The SoCal market went through the same month; its own constraints are covered in SoCal Citygate.

What happens in a mild year?

The discount runs the other way when storage is full. In 2024, Northwest Sumas averaged $2.51/MMBtu less than in 2023 and SoCal Citygate $4.55 less, which EIA attributed to high storage inventories, sustained U.S. production and mild winter temperatures.

What to watch

• Pacific region storage against its five-year average, which was 30% short before the December 2022 spike (EIA).
• BC Pipeline maintenance and outages, the trigger in 2019.
• Hydroelectric output in the Northwest, which EIA lists among the conditions reflected at Sumas.
• Constraints on routes from the Southwest, including the West Texas maintenance EIA cited in 2022. El Paso Natural Gas's Line 2000 was out of service until February 2023, when its restart was one of the reasons EIA gave for Texas price differentials narrowing.

Using the data

NATURAL_GAS_PGE_CITYGATE_USD and NATURAL_GAS_SUMAS_USD are daily prices in US dollars per MMBtu, reported on trading days. For either hub's basis, subtract NATURAL_GAS_USD (Henry Hub) on the dates both series report; the exhibit above aligns Henry Hub to PG&E Citygate's dates. Other regional hubs are compared on the natural gas hubs overview.