How the Natural Gas System
Works
Michael Armiak
October 14, 2004
Wisconsin Public Utility Institute
Energy Utility Basics
What is Natural Gas?
• A combustible, gaseous mixture of
simple hydrocarbon compounds
• Found in deep underground reservoirs
formed by porous rock
• Composed almost entirely of methane
• Includes small amounts of ethane,
propane, butane and pentane
History of Natural Gas
• First use in the U.S. occurred in 1816
• Illumination of gaslights in the streets of
Baltimore and later other cities
• By 1900, natural gas had been
discovered in 17 states
• In 1938, the federal government began
regulation through the Natural Gas Act
• Following WWII, an extensive interstate
pipeline network developed bringing
natural gas service to the whole country
Well head to Burner tip
• Production & Gathering
• Transmission & Storage
• Distribution
The Natural Gas Delivery System
Production & Gathering
Transmission & Storage
Distribution
Well head to Burner tip
• Production & Gathering
• Transmission & Storage
• Distribution
Production & Gathering
•
•
•
•
•
Exploration
Production
Separation
Gathering
Processing
Well head to Burner tip
• Production & Gathering
• Transmission & Storage
• Distribution
Purpose of Storage
• Rather than design pipelines to meet
maximum demand (and work at less
than capacity during most of the year),
gas is stored in the summer for use in
the winter
• Primarily used during large demand
swings such as heating load during very
cold weather
Storage Injection and
Withdrawal Cycles
Load Factor = Average/Peak = 40%
Swing Factor = Peak/Minimum = 10
Peak
1000
Dem and (MMcf/d)
800
600
Average
400
200
Minimum
0
Apr 1
May 1
Jun 1
Jul 1
Aug 1
Sep 1
Oct 1
Nov 1
Dec 1
Jan 1
Feb 1
Mar 1
What is Storage?
• Reservoir
Former depleted gas or oil fields except with
more wells drilled to allow gas to be drained in one
season rather than multiple years and compression
used to inject gas into field
Most efficient way to store large quantities
• LNG
Gas liquefied by cooling to -260 ºF and stored in
tanks
Well head to Burner tip
• Production & Gathering
• Transmission & Storage
• Distribution
Customers
Transmission Systems
Serve:
• LDCs
• Some Industrials
• Some Power Plants
Local Distribution
Companies (LDC)
Serve:
• Residential
• Commercial
• Industrials
• Power Plants
Distribution
• City gates
Delivery point to LDC
Gas pressure is reduced
Odorant added for leak detection
• Mains
6” to 12” diameter lines that carry gas at
300 down to a few psi to service lines
• Service Lines
Less than 2” diameter lines that carry gas
to an end users meter
National Pipeline Grid
Summary
• Production & Gathering
• Transmission & Storage
• Distribution
Production & Gathering
Transmission & Storage
Distribution
How the Natural Gas System
Works
Michael Armiak
October 14, 2004
Wisconsin Public Utility Institute
Energy Utility Basics