addressing uncertainty in oil and natural gas industry greenhouse
addressing uncertainty in oil and natural gas industry greenhouse
addressing uncertainty in oil and natural gas industry greenhouse
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Uncerta<strong>in</strong>ty Estimate for CH 4 <strong>and</strong> CO 2 Emissions from Chemical Injection Pumps:<br />
1.737 tonne CH ⎛<br />
4<br />
0.80 tonne mole CH<br />
4(facility)<br />
⎞<br />
E<br />
CH<br />
= (67 CIPs) × × 118 tonnes CH<br />
4<br />
⎜<br />
⎟=<br />
4<br />
/yr<br />
CIP - yr ⎝0.788 tonne mole CH<br />
4<br />
(default EF) ⎠<br />
1.737 tonne CH<br />
4<br />
tonne mole CH4 0.80 tonne mole CH<br />
4<br />
(facility)<br />
E<br />
CO<br />
= (67 CIPs) × × ×<br />
2<br />
CIP - yr 16.04 tonne CH 0.788 tonne mole CH (default)<br />
tonne mole <strong>gas</strong> 0.12 tonne mole CO<br />
0.8 tonne mole CH tonne mole <strong>gas</strong><br />
4 4<br />
2<br />
2<br />
× ×<br />
4<br />
44.01 tonne CO<br />
× = 48.6 tonnes CO<br />
2<br />
/yr<br />
tonne mole CO<br />
2<br />
E<br />
48.6 tonne CO<br />
=<br />
⎛118 tonne CH<br />
+<br />
21 tonne CO e ⎞<br />
× = 2,530 tonne CO e/yr<br />
⎝<br />
⎠<br />
2 4 2<br />
CO∂e ⎜<br />
⎟<br />
2<br />
yr yr tonne CH4<br />
A 5% <strong>uncerta<strong>in</strong>ty</strong> was assigned to the count of chemical <strong>in</strong>jection pumps based on expert judgment. The<br />
<strong>uncerta<strong>in</strong>ty</strong> <strong>in</strong> the emissions factor is 108% per Table 5-16 of the API Compendium. Because it is not<br />
possible to have negative emissions, the lower bound <strong>uncerta<strong>in</strong>ty</strong> will be truncated at zero. As a result, the<br />
lower <strong>and</strong> upper bound uncerta<strong>in</strong>ties are estimated separately.<br />
The <strong>uncerta<strong>in</strong>ty</strong> <strong>in</strong> the default methane content is 5.53% from the GRI/EPA Methane Study (Shires <strong>and</strong><br />
Harrison), which is provided <strong>in</strong> Table E-4 of the API Compendium. The <strong>uncerta<strong>in</strong>ty</strong> <strong>in</strong> the site specific<br />
mole % is 4%. The <strong>uncerta<strong>in</strong>ty</strong> of both the CO 2 <strong>and</strong> CH 4 emissions are calculated by apply<strong>in</strong>g Equation 4-6<br />
<strong>and</strong> us<strong>in</strong>g the relative <strong>uncerta<strong>in</strong>ty</strong> values.<br />
( ) ( )<br />
2 2<br />
U ( rel) = U( rel) +U( rel) +U rel +U rel<br />
CO2 CH4<br />
Upper:<br />
2 2 2 2<br />
Urel ( ) = 5.00 + 108 + 4.00 + 5.53 =+ 108% tonnes/yr<br />
CO2 CH4<br />
2 2<br />
E ,E AF EF Facility mole% Default mole%<br />
E ,E<br />
( )<br />
2 2 2 2<br />
U(rel)<br />
E CO & E<br />
= U( rel) 2 CH<br />
AF<br />
+ U( rel) EF<br />
+ U( rel) Facility mole%<br />
+ U( rel)<br />
Default mole%<br />
4<br />
Lower:<br />
2 2 2 2<br />
U(rel) = − 5.00 + − 100 + − 4.00 + − 5.52 =−100% tonnes/yr<br />
E CO & E<br />
2 CH4<br />
( ) ( ) ( ) ( ) ( )<br />
Uncerta<strong>in</strong>ty Estimate of CO 2 e Emissions from Chemical Injection Pumps:<br />
U ( abs) = U ( abs) + U ( abs)<br />
2 2<br />
ECO2e ECO E<br />
2 CH4<br />
Upper:<br />
2 2<br />
U ( abs) = (1.08× 48.6) + (1.08× 21× 118) = 2,690 tonnes CO e/yr<br />
ECO2e<br />
2<br />
2,690 tonnes CO e/yr<br />
Urel ( ) = 100% × =+ 106% tonnes CO e/yr<br />
( )<br />
2<br />
ECO2e<br />
2<br />
2,530 tonnes CO2e/yr<br />
Pilot Version, September 2009 F-27
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