HomeMy WebLinkAboutStaff Report 427-08City of Palo Alto
CRy Manager’s Repot t
TO:HONORABLE CITY COUNCIL
FROM:
DATE:
CITY MANAGER
NOVEMBER 17, 2008
DEPARTMENT: UTILITIES
CMR: 427:08
REPORT TYPE: INFORMATION
SUBJECT:The Natural Gas Distribution System Annual, Green House
Gas/Fugitive Emissions Report For 2008
This is an information report and no Council action is required.
BACKGROUND
The first calculation of fugitive emissions from the City-owned natural gas distribution system
was reported in December 2007 for calendar year 2006. The CPP, dated December 3, 2007,
stated that the fugitive emissions associated with the gas distribution system leakage were 19,358
metric tons of CO2e (Carbon Dioxide equivalent). This amount was 30% of the total reported
Green House Gas (GHG) emission sources calculated for the City. The GHG calculation for
calendar year 2006 was based on the natural gas system "unaccounted for" gas, which is the
reconciliation between metered gas purchases and metered gas sales to customers. In spring
2008, staff committed to returning to Council with this updated annual report on ,the Natural Gas
Distribution System Annual Green House Gas/Fugitive Emissions.
DISCUSSION
A revised GHG fugitive emission report was prepared by staff on August 27, 2008 for calendar
year 2007 (see Attachment A). The methodology utilized in 2008 to prepare the 2007
calculations (reporting on fugitive emissions for calendar year 2007) was based on the World
Resource Institute - Discussion Paper for a Natural Gas Transmission and Distribution
Greenhouse Gas Reporting Protocol (WRIR). The referenced WRIR paper recommends against
using "unaccounted for" gas for estimating fugitive emissions. While "unaccounted for" gas
includes leakage, it also includes meter measurement inaccuracies. "As a result lost and
unaccounted for gas is not an accurate surrogate for vented and fugitive emissions" (taken from
the referenced WRIR paper, page 72). The 2007 calendar year calculations were based on the
actual components of the gas distribution system using distribution system component leakage
factors recommended in the WRIR. The distribution system components were identified and
quantified using the City’s Geographic Information System, distribution maps and as-built
CMR: 427:08 Page 1 of 2
records, The distribution system component quantities used in the attached report are the same
as those submitted by the City to the Department of Transportation (DOT) in the City’s A~mual
DOT Gas Distribution System Report for Calendar Year 2007.
The revised calculation methodology for the 2007 reporting period resulted in total ff~gitive
emissions from the natural gas distribution system of 4,717 metric tons of CO2e, which is 75.6%
lower than the amount reported for calendar year 2006.
RESOURCE IMPACT
Funding for the preparation of future GHG fi~gitive emission reports will be paid fi’om Utilities
Operating Budget Funds in the form of staff salaries. Additional funding will be required to
have the calculations verified, along with the reported citywide emissions. The gas utility will
pay a portion of the estimated $7000 for the verification ofcitywide emissions.
POLICY IMPLICATIONS
The preparation of the GHG fugitive emission report is in line with the City’s Sustainability
Policy and Council’s adoption of the Climate Protection Plan.
ENVIRONMENTAL REVIEW
The actions described in this report do not meet the definition of a project pursuant to Public
Resources Code {}21065, thus no California Environmental Quality Act review is required.
ATTACHMENT
A. Natural Gas Transmission and Distribution Greenhouse Gas Report
PREPARED BY:~ohn Nguy, Engineer
reg Seoby, St. Project Engineer
Roger Cwiak, Engineering Manager
DEPARTMENT APPROVAL:
VALER~~NG
Director of Utilities
CITY MANAGER APPROVAL:
JAMs!~. ~EENE
City M__~ager
(’MR: 427:08 Page 2 o1~2
ATTACHMENT A
City of Palo Alto
Utilities Engineering Department
(Water - Gas - Wastewater)
Natural Gas Transmission and Distribution
Greenhouse Gas Report
(Calendar Year 2007)
Prepared: John Nguy
Reviewed: Greg Scoby
8/27/2008
CITY OF PAI~O AI~TO - UTILITIES ENGINEERING DEPARTMENT
Fugitive Gas Emissions Calculations (Calendar Year 2007)
Gas Distribution System Meters and Piping
(Taken from Page 80, Table VII-5. More Detailed Fugitive Emission Factors for Transmission Equipment, World Resources Institute, June 6, 2007)
CPAU Gas Distribution System Source
Commerciaillndustrial Meters1
Resldentual Customer Meters
=lastic Pipeline, Main Length2’3
=lastlc Pipeline, Main Length (Oxidation)2’~
Plastic Pipeline, Main (Leak)2’3
Protected Steel Pipeline, Main Length
Protected Steel Pipeline, Main Length (Oxidation)2
Protected Steel pipeline (Leak)2
Copper Pipeline Services=
Copper Pipeline, Services (Oxidation)2
Copper Pipeline, Services (Leak)=
Plastic Pipeline, Services=’~
Plastic Pipeline, Service (Oxidation)=’3
Plastic Pipeline, Service (Leak)2’~
Protected Steel Pipeline, Services2
Protected Steel Pipeline, Services (Oxidation)2
Protected Steel Pipelines, Services (Leak)=
Emission Factor
2.02
5.85
693.00
38.89
41.64
129.50
11.01
7.86
10.74
0.00
0.63
0,39
0.29
0.03
7.45
0.55
0.45
Units
Ib CH4/meter-year
Ib CHJmeter-year
Ib CHJmeter-year
Ib CO,/mile-year
Ib COz/mile-year
Ib CHJmeter-year
Ib CO,/mile-year
Ib CO2/mile-year
Ib CO2/service-year
lb CO2/service-year
Ib CO2/service-year
Ib CHJservlce-year
Ib CO~/service-year
Ib CO2/service-year
Ib CHJservice-year
Ib CO2/service-year
Ib CO~/service-year
Total CH4 Emissions/year =
Total CO2 Emissions/year =
CPAU-Units Units
2340.00 # of 9as meters
21060.00 # of gas meters
137.60 miles
137.60 miles
137.60 miles
69.30 miles
69.30 miles
69.30 miles
51.00 # of services
51.00 # of services
51.00 # of services
18047.00 # of services
18047.00 # of services
18047.00 # of services
1200.00 # of services
1200.00 # of services
1200.00 # of services
248,775 Ib of CH4 1J19,389 Ib of COz
Ib of CH4
4,731
123,138
95,357
8,974
548
Ib of CO2
5,351
5,730
763
545
0
32
7,065
5,243
529
8,941
656
541
1.CPA commercial/industrial meters account for approximately 10% of total number of meters (23,400 meters total taken from 2007 "All About Your Utilities Publication")
2.Mileage based on Annual Report For Calender Year 2007 Gas Distribution System submitted to the DOT.
3.Plastic pipe includes ABS, PVC, and PE materials.
Gate Station Emissions Calculations
M&R Stations (Transmission Interconnects)
(Taken from Page 79, Table VII-4. More Detailed Fugitive Emission Factors for Transmission Equipment, World Resources Institute, June 6, 2007)
CPAU-Source Emission Factor Units CPA-Units Units tb of CH~
Gate Station 61,390 Ib CH41station-year 4 # of gate stations 245,560
Total CH~ Emissions/year =245,560 Ib of CH~I
NATURAL GAS DISTRIBUTION SYSTEM GREEN-HOUSE GAS EMISSIONS (2007)
Total CH~ Emissions/year =494,335 Ib of CH~IITotal CO2 Emissions/year =19,389 Ib of CO2
NATURAL GAS DISTRIBUTION SYSTEM GREEN-HOUSE GAS EMISSIONS 2007 (CONVERTED TO COz.)
CH 4 emissions must ~e converted to CO~ According to the City Climate I~rotection Plan, Page 13, the Global Warming Potential for CH~ is 21 times the potential for’~0 2, therefore the CH 4 emissions must be inflated 21 fold to be stated as CO~
Total CH4 Emissions/year =10,381,027 Ib of COze
Total CO2 Emissions/year =19,389 Ib of CO2e
Total =10 400 417 Ib of CO2~
NATUI~L GAS DISTRIBUTION SYSTEM GREEN-HOUSE GAS EMISSIONS 2007 (COI~-VERTED TO METRIC TONS)
(1 metric ton = 2205 Ibs~I TOTAL =4,717 Metric Tons of COze ’1
11/4/2008
Explanation of the difference in calculated emissions from December 3, 2007
report:
This calculation shows a reduction of approximately 75.6% in CO2e from the
calculation as stated in the December 3, 2007, Palo Alto Climate Protection Plan.
This reduction is due to the methodology employed in the calculations. The most
recent calculation is based on the actual footages/materials/facilities of the
distribution system rather than on the "unaccounted for" quantity used last year.
This change in methodology was prompted by adhering to World Resources
Institute "Discussion Paper for a Natural Gas Transmission and Distribution
Greenhouse Gas Reporting Protocol", Final Draft Report, dated June 6. 2007.
The World Resources Institute report addresses the use of "unaccounted for" on
Page 72 under VI.8 Lost and Unaccounted for Gas, which states:
Lost and unaccounted for gas (also referred to as LUG, L&U, or UAF), refers to
the reconciliation between gas receipts and gas deliveries. The two primary
contributors to lost and unaccounted for gas are leakage from the system and
measurement inaccuracies. Some companies may also include unmeasured
gas. As a result lost and unaccounted for .qas is not an accurate surro.qate for
vented and fuqitive emissions.
The last sentence was used to make the decision not to use unaccounted for gas
in the calculations.
Utilizing the tables on Pages 79 and 80 from the World Resource Institute report,
the calculations were prepared based on the most recent system report
submitted to the Department of Transportation for fiscal year 2007.
The calculations resulted in a total fugitive emission for the City of Palo Alto
natural gas distribution system of 4,717 metric tons of CO2e. The calculation,
prepared December 3, 2007, based on the unaccounted for gas was 19,358
metric tons CO2e.
Attachment:
Page 4. 2007 Annual Report Calendar Year 2007 Gas Distribution System
Page 5. (Page 79, Table VII-4. More Detailed Fugitive Emission Factors for
Transmission Equipment, World Resources Institute, June 6, 2007)
Page 6. (Page 80, Table VII-5. More Detailed Fugitive Emission Factors for
Transmission Equipment, World Resources Institute, June 6, 2007)
8/27/2008
NOTICE: This raped ia mqu|red by 40 CFR Part 191. Failure to report may mault in a civil penalty not to exceed $100,000 for each violation Fo~’m Approved
for esoh day Ih~ y!o,19tfq.q cenllnuea up to a maximum of $1,000,000 as p~r0v!ded in 49 USC 60t22.OMB No: 2137-0522
e~ANNUAL REPORT FOR CALENDAR YEAR 20o~...!_INITIAL REPORT ~]U.$. I~padmsnl el Ti’an~portafJonP|p~gne and Hazard~Js Materiels
Safely Adrnlnlsb’aUon
PART A - OPERATOR INFORMATION
1. NAME OF oPERATOR
PALO ALTO, CITY OF
2, LOCATION OF OFFICE WHERE ADDITIONAL
INFORMATION MAY’ BE OBTAINED
250 tl~ILTON AVENUE
Numbe~ end Street
JPALO ALTO SANTA CLARA
City and County
CA 94301
State end Zip Code
STEEL
DUCTILE IRON
COPPER
CAST/WI~OUGHT
IRON
PLASTIC
1. PVC
2, PE
3. ASS
OTHER
OTHER
SYSTEM TOTAt~
3. NUMi~ER:OF’,~ERYlC..ES,.IN SYSTEM AT END OF YEAR
GAS DISTRIBUTION SYSTEM SUPPLEMENTALREPORTI-I
DOTU’~EONLY 200"/0547 -"’ 735’I,, ] I "’
3. OPE’~,~:FOR’S ~ DIGIT IDENTIFICAT’ION NUMBER
/, / ~5oetz ,,/,, /
4. HEADQUARTERS NAME & ADDRESS, IF DIFFERENT
¯Number and Street
Clty’~.d cou,ty ... "-,. :" ~ .’"
._, ".~d,--~--’~ , "-’-t" \State ane ,qp u .~-, ,..., .....
5. STATE IN WHICH SYSTEM OPERATES:I~ (provide a separate report for each state Itn whl!~lz,,s~s~8~, bfierates)
PART B - SYSTEM DESCRIPTION ~ Repo~ ~lle~ of’main and number of se~e~n’~ye~"at~d ~f,~r." " ’"
~, GENE~L " "’ .... " ’ x~’
UNPROTECTED CATHODICA’LL’Y ’~OUG~ :..DUB~IL’-,. ~.OTHER
PRO~ECTED P~S~IC IRO~"~~"x COPPER
MILES OF ~IN 0 0 0 67.2 /. :~29/8 -".~. x. ’0 l~ 0 0 0
2.. M~LES OF MAINS IN SYSTEM AT END OF YEAR ’.. ’~, " ......
MATERIAL UNKNOWN 2" OR LESS ~’ 0V~R 2" ’ .... ’,,OVER 4" OVER 8’
’ L~ ./0 0 0 O
.’-0 "’~0 0 0 0 0
OVER 12"
OTHER TOTAL
207
19298
TOTAL
69.3
0
0
0
35.8
75.7
26 .I
o
o
,206.9
AVERAGE SERVICE LENGTH 40 FEET
,STEEL
DUCTILE IRON
coPPER
CAST/WROUGHT!RON
PLASTIC
,,1, PVO ,
2. PE
~i A’~S
OTHER
OTHER
SYSTEM TOTALS
0
Form PHMSA F 7100.1-1 (12-05)
1" OR LESS
1178
51
o
3o61
1174~
2102
0
1813~
OVER1"
THRU2"
OVER ~
THRU4"
22
0
0 0
0 0
324 75
63
64
0 0
~o
899 202
OVER 4"
THRU 8"
0 0
0 . 0
0
0
62
0
0
0
63
Reproduction of this form is permitted.
OVERS"
0
0
o
o
0
O.
o
TOTAL
1200
0
51
0
3461
12150
2436
O
o
19298
Pg. 4’
Table VII-4. More Detailed Fugitive Emission Factors for Transmission Equipment
Souree
M&R~ Stations (Farm T~ps’or Dh’ect
Sales)
M&R Stations (Trans~ission
Interconnects) .....
Cast Iron Pipeline
Cast,Iron, Pipeline (Oxidation) d
Cast lro9 Pipeline (Leak)
Plastic. pipeline
Plast!e Pipeline (Oxidation) d
Plastic pipeline (Leak) ....
Protected Steel Pipeline .....
Protected Steel Pipeline (Oxidation)Protected Steel Pipeline (Leak).
Unprotected Steel Pipeline
Unprotected Steel Pipeline
(Oxidation)~
Unprotected Steel Pipeline (Leak)
Emission Factor~
4~0.8 Ib CH4/station-yr
61,390 Ib CH4/station-yr
10,079 Ib CH.~/mile:’yr
18,710 Ib CO~!mile-yr
994.2 Ib COz/mile-yr
22.51 Ib CH4/m!le-yr
1.264 Ib C0.z/mile-yr
1.353 Ib CO2/mile-yr
15.13 Ib CH~/mi!e-yr
. 1.287 lb COz/mile-yr
0.91.,85 Ib CO2/mile-yr
.275.9 lb CH4/m![e=yr
13.91 Ib CO2/mile-yr
16.55 )b Ol/mile-yr
Precisionb ± (%)
80%
80%
64%
73%
69%
225%
228%
226%
131%
136%
133%
139%
143%
141%
Source: Shires, T.M. and C.J. Loughran. GHGCalc Version 1.0 Emission Factor Documentation, Draft, Gas
Technology Institute, January 2002. Cites data from Table 4-7.a The average CH4 eoncenlration associated with these emission factors is 93.4 mole %; the average COz
concentration (for buried pipelines) is 2 mole %. If the actual concentration differs from the default value, the
emission factors shown above can be adjusted by the ratio of the site concentration to the default
concentration.
b Precision based on 90% confidence interval.
~ Metering and Pressure Regulating (M&R) stations.d A portion of CH4 emitted from underground pipeline leaks is oxidized to form CO~.
Table VII-5 includes some additional, more detailed distribution segment equipment-level
emission factors, which are taken from GHGCalc Version 1.0 (Shires, 2002). These are similar to
the level of detail shown in the Table VII-4 for the transmission segment. The pipeline leak
emission factors were derived from the GRI/EPA methane emissions project (Campbell, et. al,
Volume 9, 1996). These emission factors were not provided to this level of detail in the API
Compendium. They are also not provided in the 2005 INGAA guidance as the distribution
segment was not included within the scope of that document.
Care should be taken when applying the more detailed emission factors in Tables VI1-4 and VII-5
to avoid double-counting with the emission factors provided in Table VI1-3. That is, the meter,
pipeline, and distribution service fugitive emission factors should either be used from Table VI1-3
or from Tables VIt-4/VII-5, but not from both Table VII-3 and the latter two tables.
79 Pg. 5
J
Table VII-5. More Detailed Fugitive Emission Factors for Distribution Equipment
Sollrce
"~2’~n~ercial/lndustrial Meters
Residential Customer Meters
Cast h’on Pipeline, Main Len~il~.
Ca.s~t lr0n Pipeline, Ma..i.n Length (Oxidatio._n).c
....Cas! Iron Pipeline~ Main Lenl~th (Leak) ..
.Plastic Pipeline, Main. Length
Plastic Pipeline, Main Length (Oxidation)
Plastic Pipeline,,Main Length (Lea.k)
Protected Steel pipeline, Main Leng_t_h._
Protected Steel PipFline, Main Length (Oxidation)
..protected Steel Pip.e!ine, Main Length (Leak)
Unprotected Steel Pipeline, Main Length
Unprotected Steel Pipeline, Main Length
(Oxidation)
Unprotected .S.teel Pipeline, Main Length (Leak)
Cppper Pipeline, Services
Copper Pipeline, Services (Oxid~.t!on) c
Copper Pip~l~ine, Services (Leak)
Plastic Pipeline, Services
Plastic Pipeline, Services (Oxidation) c
Plastic Pipelin.e, Services (Leak)
Protected Steel.Pipeline~ Services
Protected Steel Pipeline, Services (Oxidation)
Protected Steel Pipeline, Services (Leak)
Unprotected Steel Pipeline, Services
Unprotected Steel P~pehne, Serwces (Ox=dahon) ..
Unprotected Steel Pipelin.F., Services (Leak)
Emission Factora
2.022 Ib CH4/meter-yr
5.847 lb.CH~/meter-yr
10,079 Ib CH4/mile->,r
18,710 lb COz/mile-yr
994.2 Ib CO~/mile-yr
69~.0 lb CH4’mile-yr
38.89 Ib COz/mile-yr
:41..64’ lb CO~/.mile-yr ....
129.5 Ib CH~/mile-yr
11.01 Ib CO2/mile-yr
7.86,2 Ib CO2/mi’ie-yr
4652 Ib CH~/mile-yr
234.5 lb CO:/mile-yr
278.9 i’b’ C02/mile-~r "’
10.74 lb CH~/service-yr
0 lb CO~/serviee-yr
.0.6322 Ib C0~/service-yr
0.3926 Ib CH~(service -yr
0.2905 Ib CO~/service-yr
0.0293 lb CO~)service-yr
...7.451 lb CHn/service -},r
0.5470 Ib CO,/service -yr
0.4505 Ib CO,/service -yr
71.81 Ib CH~/service -yr
2.196 Ib CO~/service -yr
4.276 Ib C’0~/service -y[.
Precisi°nb +
35%
17%
64%
73%
69%
282%
284%
283%
118%
123%
121%
122%
127%
154%
N/A
156% .....
222%
225%
223%
169%
173%
171%
189%
192%
Source: Shires, T.M. and C.J. Loughran. GHGCalc l"ersion 1.0 Emission Factor Documentation, Draft,
Gas Technology Institute, January 2002. Cites data from Table 4-10.a The average CH~ concentration associated with these emission factors is 93.4 mole %; the average CO~
concentration (for buried pipelines) is 2 mole %. If the actual concentratlbn differs from the default value,
the emission factors shown above can be adjusted by the ratio of the site concentration to the default
concentration.
~ Precision based on 90% confidence interval.
~ A portion of CH4 emitted from underground pipeline leaks is oxidized to form (~O~.
VII.2.3 Facility and Equipment Level Emission Factor Considerations
An independent review of the API Compendium emission factors conducted for the California
Energy Commission pointed out some areas for improvement (1CF, 2005). Those related to NG
T&D sources included fugitive emissions from plastic pipelines in the distribution sector and
compressor seals.
For centrifugal compressors, two technologies are available to seal the rotating sha~ at one or both
ends of the compressor case. The more mature technology, referred to as a wet seal, uses oil. This
80 Pg. 6