Partner Reported Opportunities (PROs) PRO Fact Sheet No. 504 for Reducing Methane Emissions 

Eliminate Unnecessary Equipment 

and/or Systems 

Technology/Practice Overview 

Description 

As operating parameters change over 

time, Partners in all sectors have found 

that certain pieces of equipment or 

systems initially crucial to operations 

have become superfluous or greatly 

exceed operational demands to the point 

of inefficiency. Production facilities, for 

example, are designed to accommodate

the maximum expected production rate.

As fields mature, pressure decline causes 

production to decrease, resulting in 

excess processing capacity, inefficient 

operation, and unnecessary onsite 

emissions. 

For example, crude oil is processed in 

the field to separate lighter 

hydrocarbons from produced waters. 

This process can lead to methane 

venting when the resulting crude oil and

water flows are stored in fixed roof 

tanks. 

As production decreases, partners have 

reported reducing the quantity of 

methane emissions by consolidating and 

centralizing their liquid storage

facilities. Through a reduction in the 

number of field tanks, Partners have 

been able to reduce methane emissions 

associated with standing losses due to 

temperature variations and working 

losses resulting from changing fluid 

levels and tank agitation. Consolidated 

storage facilities are also more economic

for vapor recovery. 

While changing conditions allow 

Partners to eliminate some initial 

equipment, they can also necessitate the 

addition of equipment. For example, as 

Estimated 

Gas Price 

Annual 

Methane 

Savings 

Value of 

Annual

 Gas Savings* 

Estimated 

Implementation Cost 

Incremental 

Operating 

Cost 

Payback 

(months) 

$7.00/Mcf 4,200 Mcf $31,300 $10,000 $0 4 Months 

$5.00/Mcf 4,200 Mcf $22,300 $10,000 $0 5 Months 

$3.00/Mcf 4,200 Mcf $13,400 $10,000 $0 9 Months 

Economic and Environmental Benefits 

Economic Evaluation 

Additional Benefits 

 Operations and maintenance cost savings 

 Increased operational efficiency 

Estimated annual methane emission reductions Consolidate storage tanks: 4,200 Mcf per tank 

Methane Savings 

* Whole gas savings are calculated using a conversion factor of 94% methane in pipeline quality natural gas. 

Compressors/Engines 

Dehydrators 

Directed Inspection & 

Maintenance 

Pipelines 

Pneumatics/Controls 

Tanks 

Valves 

Wells 

Other 

Applicable Sector(s) 

Production 

Processing 

Transmission 

Distribution 

Other Related Documents: 

Install Pressurized Storage of 

Condensate, PRO No. 501 

Convert Water Tank Blanket 

from Natural Gas to Produced 

CO2 Gas, PRO No. 503 

Installing Vapor Recovery Units 

on Storage Tanks, Lessons 

Learned 
 

 

 

 

 

PRO Fact Sheet No. 504 Continued 

Consolidate Crude Oil Production and Water Storage Tanks and 

Eliminate Unnecessary Equipment and/or Systems 

a high-pressure gas well matures, the initial separator

and glycol unit would be oversized and require 

downsizing. At the same time, a compressor, water 

storage tank, and salt water disposal system might need 

to be added to continue production. The operator would

need to evaluate the remaining gas reserves to justify

these additional expenditures. 

The more than 17 Partners that have reported this PRO 

found that eliminating or downgrading unnecessary 

pieces of equipment or systems increased efficiency,

lowered operation and maintenance costs, and reduced

methane emissions. Equipment eliminated or 

downgraded included tanks, compressors, glycol 

dehydrators, truck loading sites, heater/treater units, gas

-driven water treating flotation cells, and CO2 membrane 

units. 

Operating Requirements 

In general, eliminating or downgrading unnecessary 

equipment will not affect operating requirements, though 

some changes may require a facility redesign and the 

removal of unnecessary auxiliary systems. 

Applicability 

Facilities operating well below design rates should be

good candidates for eliminating unnecessary equipment

and/or systems. 

Methane Emissions 

When eliminating unnecessary equipment from facilities, 

reductions will vary according to the type of equipment 

eliminated, the equipment's efficiency/leakage rate, and 

equipment/facility throughput. 

For example, emissions from crude oil production and

water storage tanks occur due to the venting of gas 

liberated from standing and working losses. Methane 

emissions reductions can be estimated using EPA’s AP42 guidelines or API’s “E&P Tank” software program for

specific tank alternatives. 

Economic Analysis 

Basis for Costs and Emissions Savings 

Partner reported reductions for this practice have ranged 

between 5 and 130,000 Mcf per year. 

Methane emissions reductions of 4,200 Mcf per year 

apply to the consolidation of wellhead storage tanks in 

one central vessel. Methane emissions savings of 5 Mcf 

The average methane content of natural gas varies by natural gas 

industry sector. The Natural Gas STAR Program assumes the 

following methane content of natural gas when estimating 

methane savings for Partner Reported Opportunities. 

Production 79 % 

Processing 87 % 

Transmission and Distribution 94 % 

Methane Content of Natural Gas 

per year are associated with the removal of 10 stack pack 

separators and 3 glycol dehydrators. Methane emissions 

savings of 130,000 Mcf per year are associated with the 

elimination of 42 compressors at a processing facility. 

Discussion 

Elimination of unnecessary equipment and/or systems

can have a quick payback. Primary benefits are 

increased operational efficiency and reduced operation 

and maintenance costs. Associated benefits are the 

methane emission reductions from the elimination of 

unnecessary equipment and improvement in processing

efficiency. 

EPA provides the suggested methane emissions estimating methods contained 

in this document as a tool to develop basic methane emissions estimates only. 

As regulatory reporting demands a higher-level of accuracy, the methane emission estimating methods and terminology contained in this document may not 

conform to the Greenhouse Gas Reporting Rule, 40 CFR Part 98, Subpart W 

methods or those in other EPA regulations. 

2011 2