Table 7-1

Report Name Affiliation

Year 

of 

Report

Activity 

Factors

Emission 

Figures

Control 

Information

VOC Emissions from Oil and Condensate Storage 

Tanks1

Texas Environmental 

Research Consortium

2009 Regional X X

Lessons Learned from Natural Gas STAR 

Partners: Installing Vapor Recovery Units on 

Crude Oil Storage Tanks2

U.S. Environmental 

Protection Agency

2003 National X

Upstream Oil and Gas Storage Tank Project Flash 

Emissions Models Evaluation – Final Report

Texas Commission on 

Environmental Quality

2009 Regional X

Initial Economics Impact Analysis for Proposed 

State Implementation Plan Revisions to the Air 

Quality Control Commission’s Regulation 

Number 3 and Regulation Number 7 – Regulation 

3, Parts A, B, and C; Regulation 7, Sections IXVIII, Per C.R.S. 25-7-110.5

Colorado 2008 n/a X

E&P Tanks American Petroleum 

Institute

National X
Table 7-2. Model Condensate Tank Batteries

Model Condensate Tank Battery

Parameter E F G H

Condensate throughput (bbl/day)

a

15 100 1,000 5,000

Condensate throughput (bbl/yr) a5,475 36,500 365,000 1,825,000

Number of fixed-roof product storage tanks a

210 barrel capacity 4 2

500 barrel capacity 2 2

1,000 barrel capacity 2 4

Estimated tank battery population (1992)a12,000 500 100 70

Estimated tank battery population (2008) b14,038 585 117 82

Total number of tanks (2008) b56,151 2,340 468 328

Percent of number of tanks in model condensate 

tank battery

94.7% 3.95% 0.789% 0.552%

Percent of throughput per model condensate tank 

batterya

26% 7% 15% 51%

Total tank battery condensate throughput 

(MMbbl/yr)

c

32.8 9.11 18.2 63.8

Condensate throughput per model condensate 

battery (bbl/day)

6.41 42.7 427 2,135

Condensate throughput per tank (bbl/day) 1.60 10.7 106.8 534

Minor discrepancies may be due to rounding.

aDeveloped for NESHAP (Reference INSERT CROSS REFERENCE TO BID).

b

Population of tank batteries for 2008 determined based on condensate throughput increase from 106 

MMbbl/yr in 1992 to 124 MMbbl/yr in 2008 (Reference INSERT CROSS REFERENCE TO GHG 

INVENTORIES).

c

2008 condensate production rate of 124 MMbbl/yr distributed across model tank batteries using same 

relative ratio as developed for NESHAP (Reference INSERT CROSS REFERENCE TO BID).
Table 7-3. Model Crude Oil Tank Batteries

Model Crude Oil Tank Battery

Parameter E F G H

Percent of number of condensate tanks in model 

size rangea

94.7% 3.95% 0.789% 0.552%

Number of tanksb491,707 20,488 4,098 2,868

Percent of throughput across condensate tank 

batteries

26% 7% 15% 51%

Crude oil throughput per model plant category 

(MMbbl/yr)

351 97.5 195 683

Crude oil throughput per tank (bbl/day) 1.96 13.0 130 652

Minor discrepancies may be due to rounding.

a

Same relative percent of tank population developed for model condensate tank batteries. Refer to Table 

7-2. 

b Calculated by applying the percent of number of condensate tanks in model size range to total number 

of crude oil tanks (519,161 crude oil tanks estimated for 2008).INSERT CROSS REFERENCE FOR 

LESSONS LEARNED

c

Same relative percent of throughput developed for model condensate tank batteries. Refer to Table 7-

2.
Table 7-4 Summary of Data from E&P TANKS Modeling

Parameter*

Average of 

Dataset

Average of 

Tanks with 

API Gravity 

> 40 degrees

Average of 

Tanks with 

API Gravity 

< 40 degrees

Throughput Rate (bbl) 500 500 500

API Gravity 40.6 52.8 30.6

VOC Emissions (tpy) 531 1046 107

Emission factor (lb/bbl) 5.8 11.5 1.18

*

Information from analysis of E&P Tanks dataset, refer to Appendix ???
Table 7-5. Model Tank VOC Emissions

Parameter

Model Tank Battery

E F G H

Model Condensate Tank Batteries

Condensate throughput per tank (bbl/day) 1.60 10.7 107 534

VOC Emissions (tpy)b3.35 22.3 223 1117

Model Crude Oil Tank Batteries 

Crude Oil throughput per tank (bbl/day)c2.0 13 130 652

VOC Emissions (tpy)d0.4 2.80 28 140

a Condensate throughput per tank from table 7-2.

b Calculated using the VOC emission factor for condensate tanks of 11.5 lb VOC/bbl condensate.

c

 Crude oil throughput per tank from table 7-3.

d Calculated using the VOC emission factor for crude oil tanks of 1.18 lb VOC/bbl crude oil.
Table 7-6. Nationwide Baseline Emissions for Storage Tanks

Model Tank

E F G H Total

Model Condensate Tank Batteries

Total number of tanks (2008) 56,151 2,340 468 328 59,286

Total projected number of new or modified tanks 

(2015)*

4,630 193 39 27 4,889

Number of uncontrolled tanks in absence of 

federal regulation†

1,688 70 14 10 1,782

Uncontrolled VOC Emissions from Model Tank‡3.35 22.3 223 1,117 1,366

Total Nationwide Uncontrolled VOC Emissions 5,657 1,572 3,143 11,001 21,373

Model Crude Oil Tank Batteries

Total number of tanks (2008) 491,707 20,488 4,098 2,868 519,161

Total projected number of new or modified tanks 

(2015)*

40,548 1,689 338 237 42,812

Number of uncontrolled tanks in absence of 

federal regulation†

14,782 616 123 86 15,607

Uncontrolled VOC Emissions from Model Tank‡ 0.4 2.80 28 140 171

Total Nationwide Uncontrolled VOC Emissions 6,200 1,722 3,444 12,055 23,421

Minor discrepancies may be due to rounding

* Calculated by applying the expected 8.25 percent industry growth to the number of tanks in 2008.

† Calculated by applying the estimated 36 percent of tanks that are uncontrolled in the absence of a 

Federal Regulation to the total projected number of new or modified tanks in 2015.

‡ VOC Emissions from individual model tank, see Table 7-5.
Table 7-7. Total Capital Investment and Total Annual Cost of a Vapor Recovery Unit

Cost Item*

Capital 

Costs

($)

NonRecurring, 

One-time 

Costs ($)

Total 

Capital 

Investment 

($)†

O&M 

Costs ($)

Savings 

due to Fuel 

Sales 

($/yr)

Annualized 

Total Cost 

($/yr)

‡

VRU $78,000

Freight and Design $1,500

VRU Installation $10,154

Maintenance $8,553

Recovered natural gas ($1,063)

Subtotal Costs (2007) $78,000 $11,654 $8,553 ($1,063)

Subtotal Costs 

(2008)§

$85,423 $12,763 $98,186 $9,367 ($1,164)

Annualized costs 

(using 7% interest, 15 

year equipment life)

$9,379 $1,401 n/a n/a $18,983

* Assume cost data provided is for the year 2007. Reference insert cross reference to EIA from 

Colorado

†

Total Capital Investment is the sum of the subtotal costs for capital costs and nonrecurring one-time 

costs.

‡

Total Annual Costs is the sum of the annualized capital and recurring costs, o&m costs, and savings 

due to fuel sales.

§ Costs are escalated to 2008 dollars using the CE Indices for 2007 (525.4) and 2008 (575.4). insert 

cross reference to CE index
Table 7-8. Total Capital Investment and Total Annual Cost of a Flare

Cost Item*

Capital 

Costs

($)

NonRecurring, 

One-time 

Costs ($)

Total 

Capital 

Investment 

($)†

O&M 

Costs ($)

Annualized 

Total Cost 

($/yr)

‡

Flare $16,540

Freight and Design $1,500

Flare Installation $6,354

Auto Igniter $1,500

Surveillance System§$3,600

Pilot Fuel $1,897

Maintenance $2,000

Data Management $1,000

Subtotal Costs (2007) $21,640 $7,854 $4,897

Subtotal Costs (2008) ** $23,699 $8,601 $32,301 $5,363

Annualized costs (using 7% 

interest, 15 year equipment life)

$2,602 $944 n/a $8,909

* Assume cost data provided is for the year 2007. Reference insert cross reference to EIA from 

Colorado

†

Total Capital Investment is the sum of the subtotal costs for capital costs and nonrecurring one-time 

costs.

‡

Total Annual Costs is the sum of the annualized capital and recurring costs, o&m costs, and savings

due to fuel sales.

§

Surveillance system identifies when pilot is not lit and attempt to relight it, documents the duration of 

time when the pilot is not lit, and notifies and operator that repairs are necessary.

**Costs are escalated to 2008 dollars using the CE Indices for 2007 (525.4) and 2008 (575.4). insert 

cross reference to CE index
Table 7-9. Secondary Impacts for Flares used to Control Condensate and Crude Oil Storage 

Tanks

Pollutant

Emission 

Factor Units

Emissions per 

Storage Tank 

(tpy)*

THC 0.14 lb/MMBtu 0.0061

CO 0.37 lb/MMBtu 0.0160

CO2 60 Kg/MMBtu†5.62

NOX 0.068 lb/MMBtu 2.95E-03

PM 40 μg/l (used lightly smoking flares 

due to criteria that flares should 

not have visible emissions i.e. 

should not smoke)

5.51E-05

* Converted using average saturated gross heating value of the tank vapor (1,968 Btu/scf) and an average 

vapor flow rate of 44.07 Mcf per tank. See Appendix ??.

† CO2 emission factor obtained from 40 CFR Part 98, subpart Y, Equation Y-2.
Table 7-10. Options for Throughput Cutoffs for Condensate Tanks

Regulatory 

Option

Throughput 

Cutoff 

(bbl/day)

Equivalent 

Emissions 

Cutoff 

(tpy)*

Emission 

Reduction 

(tpy)†

Annual 

Costs for 

VRU 

($/yr)‡

Cost 

Effectiveness 

($/ton)

Number 

of 

impacted 

units§

1 0.5 3.0 2.89 $18,983 $6,576 1782

2 1 6.1 5.77 $18,983 $3,288 94

3 2 12.2 11.55 $18,983 $1,644 94

4 5 30.4 28.87 $18,983 $658 24

*

Emissions calculated using emission factor of 33.3 lb VOC/bbl condensate and the throughput 

associated with each option. 

† Calculated using 95 percent reduction

‡ Refer to Table 7-7 for VRU Annual Costs.

§ Number of impacted units determined by evaluating which of the model tank categories and tank 

populations associated with each model tank category (refer to Table 7-6) would be subject to each 

regulatory option. A model tank category was considered to be impacted by the regulatory option if its 

throughput and emissions were greater than the cutoffs for the option.
Table 7-11. Options for Throughput Cutoffs for Crude Oil Tanks

Regulatory 

Option

Throughput 

Cutoff 

(bbl/day)

Equivalent 

Emissions 

Cutoff 

(tpy)*

Emission 

Reduction 

(tpy)†

Annual 

Costs for 

VRU 

($/yr)‡

Cost 

Effectiveness 

($/ton)

Number 

of 

impacted 

units§

1 1 0.3 0.28 $18,983 $68,432 15607

2 5 1.5 1.4 $18,983 $13,686 825

3 20 5.8 5.55 $18,983 $3,422 209

4 50 14.6 13.87 $18,983 $1,369 209

*

Emissions calculated using emission factor of 33.3 lb VOC/bbl condensate and the throughput 

associated with each option. 

† Calculated using 95 percent reduction

‡ Refer to Table 7-7 for VRU Annual Costs.

§ Number of impacted units determined by evaluating which of the model tank categories and tank 

populations associated with each model tank category (refer to Table 7-6) would be subject to each 

regulatory option. A model tank category was considered to be impacted by the regulatory option if its 

throughput and emissions were greater than the cutoffs for the option.
Table 7-12. Nationwide Impacts of Regulatory Options

*

It was assumed for the purposes of estimating nationwide impacts that 50 percent of facilities would install a flare and 50 percent a VRU. This accounts for the 

operational difficulties of using a VRU.

† Methane Reductions calculated by applying the average Methane to VOC factor from the E&P Tanks Study (see Appendix ??). Methane:VOC = 0.219

‡

For purposes of evaluating NSPS impact, impacts were determined for an average tank by calculating total VOC emissions from all tanks and dividing by the total 

number of impacted tanks to obtain an average VOC emissions per tank.

Model 

Plant 

Category

Number 

of 

Sources 

subject to 

NSPS*

VOC 

Emissions 

for a 

Typical 

Tank 

(tpy)

Capital 

Cost for 

Typical 

tank*

($)

Annual Cost for a 

Typical Tank*

($/yr) Nationwide Emission 

Reductions (tpy)†

VOC Cost Effectiveness 

($/ton)

Methane Cost 

Effectiveness 

($/ton)

Total Nationwide Costs

(million $/year)

Without

Savings

With

Savings VOC Methane†

Without 

savings

With 

savings

Without 

savings

With 

savings

Capital 

Cost

Annual 

without 

savings

Annual 

with 

savings

Regulatory Option 2: Condensate Tanks

F 70 22.3 $65,243 14,528 13,946 1,483 325 685 658 3129 3004 4.57 1.02 0.98

G 14 223 $65,243 14,528 13,946 2,966 649 68 66 313 301 0.913 0.203 0.195

H 10 1117 $65,243 14,528 13,946 10,612 2,322 14 13 62.6 60.1 0.652 0.145 0.139

Regulatory Option 3: Crude Oil Tanks

G 123 28 $65,243 14,528 13,946 3,272 716 546 524 2496 2396 8.02 1.79 1.71

H 86 140 $65,243 14,528 13,946 11,438 2,503 109 104 499 479 5.61 1.25 1.20

Combined Impacts‡

Typical 

Tank

304 103 $65,243 14,528 13,946 29,746 6,490 149 143 680 652 19.8 4.41 4.24
 

1

Hendler, A., (URS Corporation), Nunn, J. (COMM Engineering), and J. Lundeen (Trimeric Corporation). VOC Emissions from Oil and Condensate Storage Tanks – Final 

Report. Prepared for Texas Environmental Research Consortium. The Woodlands, TX. October 31, 2006 (revised April 2, 2009)

2