1. Reduce Distribution System Pressure
Lessons Learned from Natural Gas STAR
Distribution Technology Transfer Teleconference
American Gas Association, Southern Gas Association,
Northeast Gas Association, Ohio Gas Association,
Texas Gas Association, Western Energy Institute, and
EPA’s Natural Gas STAR Program
May 17, 2005

2. EPA Natural Gas STAR
The Natural Gas STAR Program is a flexible, voluntary partnership between EPA and the oil and natural gas industry designed to cost-effectively reduce methane emissions from natural gas operations
338 Bcf methane savings since 1993
49 AGA members have partnered with Natural Gas STAR
26 SGA members have partnered with Natural Gas STAR
AGA and SGA members report savings of over 123 Bcf ($371 million) gas since 1993
62% of AGA comes from January 2005 presentation we gave to AGA, based on number of customers. All other numbers come from the endorser “web sites” pdf files we created in December 2004.

3. U.S. Industry Participation
117 Program Partners
62% of transmission
26 partners
60% of distribution
48 partners
51% of production
32 partners
63% of processing
12 partners
Numbers as of 4/29/05 (last partner added was to production sector. Southwestern Energy Company)

4. Reduce Distribution System Pressure: Agenda
Part 1: Problem Description
Methane Losses
Methane Recovery
Discussion Questions
Part 2: Is Methane Recovery Profitable?
Savings
Costs
Economics
Part 3: Industry Experience

5. Distribution Sector Methane Losses
Distribution sector is 19% of natural gas and oil methane emissions
Emissions
1 Bcf
Oil Downstream
2 Bcf
Reductions
Processing
36 Bcf
Production
148 Bcf
7 Bcf
Distribution
68 Bcf
24 Bcf
Transmission & Storage
101 Bcf
Inventory of US Greenhouse Gas Emissions and Sinks
18 Bcf

6. Methane Losses by Source
Nearly all distribution sector methane losses are unintended fugitive leaks
Protected Steel Mains/Services
3 Bcf
Other Sources
2 Bcf
M&R Stations
17 Bcf
Customer Meter Leaks
6 Bcf
Plastic Mains/Services
8 Bcf
Cast Iron Mains
8 Bcf
Unprotected Steel Mains/Services
13 Bcf
Regulator Stations
11 Bcf

7. What is the Problem? Fugitive leaks
Lead to higher maintenance costs
Cause product loss
Peak demand pressures are set for extended periods, but necessary only a small fraction of the time
Higher than necessary system pressure intensifies leakage
Increases maintenance costs and product loss
Increases “under-registered gas”

8. Distribution System Fugitive Sources
Facilities
Gate Stations: Reduce pressure and meter gas from
transmission lines
District Regulators: Further reduce pressure for customer
use
Lines:
High Pressure Mains: Carry gas from gate stations to
customer districts
Low Pressure Mains: Carry gas from district regulators to
service lines
Services: Branch-off from high or low pressure
mains to customer meter

9. Methane Recovery
Gas STAR Partners adjust system pressures for shorter intervals to better match current demand
Minimizes leaks and product loss
Reduces maintenance
Reduces under-registered gas

10. Methane Recovery Two approaches to match pressure with demand
Manual, periodic pressure regulation
Change of procedures to adjust DR set points
Low capital cost, higher operating costs
Automatic, near real-time pressure regulation
Installation of control systems to adjust DR set points
High capital cost, lower operating cost

11. Manual Pressure Regulation
Adjust DR set-points more frequently during scheduled maintenance
Example: from annual to semi-annual
Example: from semi-annual to quarterly
Example: from quarterly to monthly adjustments
Partners sometimes change pressure in steps to avoid system shock or pressure oscillations

12. Automatic Pressure Regulation
Automatic regulation can adjust DRs multiple times per day, more closely matching real demand with the lowest necessary pressures
Leads to lowest leak rates, less maintenance, less under-registered gas
Multiple degrees of automation technology
Lowest cost: clocking and temperature solenoids
Medium cost: remote terminal unit control systems
Highest cost: centralized supervisory computer

13. Automatic Pressure Regulation Alternatives
AUTOMATION FEATURES

14. Review of Part 1 Questions?
Methane emissions
Distribution systems and pressure regulation
Methods for matching pressure to demand
Questions?