# Presentation: 513328

## 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**

## 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

**Notes:**
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.

## U.S. Industry Participation

**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**

**Notes:**
Numbers as of 4/29/05 (last partner added was to production sector. Southwestern Energy Company)

## Reduce Distribution System Pressure: Agenda

- Part 1: Problem Description
**Methane Losses**
**Methane Recovery**
**Discussion Questions**
- Part 2: Is Methane Recovery Profitable?
**Savings**
**Costs**
**Economics**
**Discussion Questions**
- Part 3: Industry Experience

## Distribution Sector Methane Losses

- Distribution sector is 19% of natural gas and oil methane emissions

- Inventory of US Greenhouse Gas Emissions and Sinks 1990 - 2003

**Emissions**

**Reductions**

**Production**
**148 Bcf**

**24 Bcf**

**Transmission & Storage**
**101 Bcf**

**18 Bcf **

**1 Bcf **

**Oil Downstream  **
**2 Bcf**

**Processing**
**36 Bcf**

**7 Bcf **

**Distribution **
**68 Bcf**

## Methane Losses by Source

- Nearly all distribution sector methane losses are unintended fugitive leaks

**Unprotected Steel Mains/Services**
**13 Bcf**

**Cast Iron Mains**
**8 Bcf**

**Customer Meter Leaks**
**6 Bcf**

**Regulator Stations**
**11 Bcf**

**M&R Stations **
**17 Bcf**

**Plastic Mains/Services**
**8 Bcf**

**Other Sources **
**2 Bcf**

**Protected Steel Mains/Services**
**3 Bcf**

## 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”**

## 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**

## 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**

## 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**

## 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

## 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**

## Automatic Pressure RegulationAlternatives

## Review of Part 1

- Methane emissions
- Distribution systems and pressure regulation
- Methods for matching pressure to demand

**Questions?**