What is Chicago Citygate?

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

What does "citygate" mean?

A citygate is where gas leaves the interstate pipelines and enters a local distribution system, so a citygate price includes the cost of moving gas to that system. That places citygate hubs at the demand end of the network rather than in a production basin. EIA describes Chicago Citygate as the primary pricing hub for end users in Chicago and parts of the upper Midwest.

Which pipelines meet at Chicago?

Seven major interstate pipelines converge there, carrying gas from Canada, the Southwest and the Gulf of Mexico (EIA). Two of them, ANR Pipeline and Natural Gas Pipeline Company of America (NGPL), are named by EIA as major lines bringing gas into the Midwest. Three of the seven connect to the Henry Hub region, and EIA ties the close relationship between the two prices to that link.

Supply from three directions is the contrast with Algonquin Citygate in New England, where EIA describes supply as constrained by the region's limited pipeline capacity and price volatility as tied to peak demand.

Why does Chicago usually track Henry Hub?

Three reasons from EIA's description of the hub: pipeline links to the Henry Hub region, proximity to storage, and abundant infrastructure that moderates seasonal and daily price swings. Storage near the market means gas injected in summer can meet winter peaks without all of it arriving by pipeline on the coldest day. The national weekly storage balance is tracked on our natural gas storage page.

When does Chicago break away?

When cold is severe enough that pipelines and storage cannot keep up, Chicago reprices against local demand instead of Henry Hub. Two dated episodes:

Prices in $/MMBtu from EIA's Natural Gas Weekly Updates of 9 January 2014 and 18 February 2021. In 2014, EIA wrote that Chicago prices "normally are very close to Henry Hub prices" before recording the jump. The January 2014 episode also shows Chicago's advantage over the East: prices in New England, New York and the Mid-Atlantic rose further than in the Midwest that week, and Northeast prices reached $30 to $40 above Henry Hub (EIA).

The February 2021 row shows the reverse case. Uri cut production as far south as the Gulf Coast, so Henry Hub spiked too, and by 17 February Chicago was trading below it. The basis to Henry Hub therefore depends on where the cold and the lost supply are, not on the temperature in Chicago alone.

What is an operational flow order?

Uri also shows the ceiling is set elsewhere. In the same week EIA reported the ONEOK Gas Transportation delivery point in Oklahoma at $1,192.86/MMBtu on 17 February, the highest price on record for any major hub back to 1993, and Henry Hub at its highest nominal price in that history. Against those, Chicago's $129.52 peak five days earlier was a large move at a hub that EIA describes as moderated by storage and pipeline access, not an outlier among hubs.

An OFO is a pipeline's order to shippers to keep the gas they put in and take out in balance, issued to protect system integrity. In January 2014, ANR and NGPL issued OFOs and other Midwest pipelines issued critical notices that curtailed normal flow scheduling (EIA). Notices like these show a system near its limit, which is when Chicago has moved away from Henry Hub.

How is Chicago Citygate traded?

ICE lists monthly cash-settled futures on the hub. The Chicago Fixed Price Future settles on NGI's monthly bidweek price for Chicago Citygate, in 2,500 MMBtu contracts. The Chicago Index Future settles on the average of Gas Daily's daily Chicago citygate prices minus that NGI bidweek price, so it hedges the difference between daily and monthly gas at the same location. A Midwest utility or marketer that buys at Chicago can hedge Henry Hub with NYMEX futures and the remaining difference with these contracts.

What to watch

• Midwest temperature forecasts, the trigger for every episode above.
• Pipeline notices from ANR, NGPL and the other lines into Chicago: OFOs and critical notices precede the price moves.
• Storage withdrawals. The week ending 10 January 2014 set a record net withdrawal of 287 Bcf (EIA); large draws show how much of the peak storage is covering.
• The basis to Henry Hub, from the exhibit above. A widening premium in a cold week is the first sign Chicago has decoupled. For the method, see basis spreads explained.

Using the data

NATURAL_GAS_CHICAGO_USD is the Chicago Citygate daily price in $/MMBtu, published on trading days. Pair it with NATURAL_GAS_USD (Henry Hub) on shared dates for the basis; Henry Hub rows can include weekends, so filter to the dates both series report. The other hubs in this series are compared on the natural gas hubs page.