SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 1:
What is the size of the gas compressors being replaced and the new electric
compressor? Please provide in horsepower and in any available measure of gas
compressed per hour.
RESPONSE 1:
The existing facility consists of three identical turbine driven compressor (TDC) trains.
Each train consists of: 1) a natural gas fired turbine gas generator, General Electric
LM1500: 2) a power turbine wheel, Clark DJ125G: 3) a speed increasing gear, Western
Gear 4116HSS and: 4) a centrifugal two-stage compressor, Clark 272B 3/4.
The GE LM1500 was originally rated at 15,000 HP ISO rating. ISO is a standard rating
formula that uses 59.5 degrees F as the inlet ambient air temperature, at sea level, with
no inlet or outlet pressure losses. Correcting for actual site conditions at Aliso Canyon,
the site rating of the LM1500 is approximately 12,000 HP. As the unit ages, efficiency
drops and maintenance/rebuild is required. Over the many years of service, even after
rebuilds, the original horsepower output can never be achieved. The Benedict-WebbRubin (BWR) equation currently calculates the average existing horsepower at 10,200
to 10,400 hp. At end-of-cycle conditions, when the field inventory is at its highest and
compressor duty is also at its highest, the existing facility is capable if injecting 300
mmcfd with a suction pressure of 550psig and a discharge pressure of 2900psig.
Each of the three new electric driven compressor trains will consist of: 1) a 22,000 HP
VFD electric motor; 2) speed increasing gear and; 3) a two-stage centrifugal
compressor. At end-of-cycle conditions, the new facility will be capable of injecting 450
mmcfd with a 550psig suction and a 3400psig discharge. Electric motors are not
derated by elevation or normal temperatures; therefore the horsepower rating for each
motor is 22,000 hp.
1
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 2:
Please provide an analysis of the monthly energy consumed by the three gas turbine
compressors, as well as the monthly kWh of electricity consumed by the proposed new
electric compressor by time period and peak kW of electricity demand (both coincident
with peak electrical usage periods and non-coincident peak).
RESPONSE 2:
Taking the three year period from 2005 to 2007, the average monthly gas consumption
of the compressors was as follows:
Gas Consumption (MMBtu)
2005 - 2007
(Average)
MMBtu
January
February
March
April
May
June
July
August
September
October
November
December
4,382
126
43,368
204,231
276,771
202,681
111,229
67,275
152,435
166,262
63,702
21,403
2
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
RESPONSE 2 (continued):
Converting the above gas consumption to an equivalent electric consumption, and
taking into consideration the time of day of usage, yields the following profile:
Year 2005 - 2007 Average
Energy Consumption (kWh)
Sum OnSum MidPeak
Peak
Energy
Energy
Month
January
February
March
April
May
June
2,185,145
3,427,830
July
620,643
1,092,916
August
168,416
283,920
September
1,193,628
2,033,539
October
November
December
-
Sum OffPeak
Energy
8,390,435
5,971,337
4,195,744
7,304,718
-
Win MidPeak
Win Off-Peak
Energy
Energy
54,105
248,685
8,727
1,000,426
1,995,939
4,647,048
9,463,476
7,017,655
12,104,698
3,301,886
8,185,315
1,000,953
3,400,291
273,853
1,204,926
This profile can be stated as follows to better highlight the relative amount of energy
consumed monthly in each of the time periods defined in the SoCal Edison tariffs.
Energy Consumption (% of Total)
Sum On- Sum MidPeak
Peak
Energy
Energy
Month
January
February
March
April
May
June
2.4%
3.8%
July
0.7%
1.2%
August
0.2%
0.3%
September
1.3%
2.2%
October
November
December
-
3
Sum OffPeak
Energy
9.2%
6.6%
4.6%
8.0%
-
Win MidPeak
Energy
0.1%
0.0%
1.1%
5.1%
7.7%
3.6%
1.1%
0.3%
Win OffPeak
Energy
0.3%
0.0%
2.2%
10.4%
13.3%
9.0%
3.7%
1.3%
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
RESPONSE 2 (continued):
The peak demand for this energy profile is shown below:
Metered Demand (kW)
Sum OnPeak
Demand
Month
January
February
March
April
May
June
27,981
July
27,639
August
9,949
September
28,156
October
November
December
-
Sum MidPeak
Demand
28,416
28,294
22,122
28,655
-
Sum OffPeak
Demand
28,650
28,716
28,545
28,889
-
Win MidPeak
Win Off-Peak
Demand
Demand
9,598
9,873
2,726
23,139
16,275
28,703
29,152
28,915
29,105
28,741
28,856
25,663
25,877
9,655
28,766
*At full capacity, new compressor may achieve peak demand of 66,000/1.34 kW.
4
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 3:
Please provide a comparison of the energy efficiency of new modern gas turbine
compressors with the old inefficient compressors that SoCal proposes to remove.
RESPONSE 3:
See response to Question 1 of this data request.
The original ISO rating for the LM1500 was 15,000hp at a 9470Btu/hp-hr heat rate. At
the current average 10,300hp and a 80 degree F inlet temperature the attached curve
indicates a 12,000 Btu/hp-hr heat rate. As a check, the current average fuel rate to the
LM1500s is 131,000scfh. At a 1020 Btu/scf, the calculated heat rate is 12,972 Btu/hphr.
A new gas turbine of similar size, for example, would be a Solar Mars 100 with an ISO
rating of 15,000 HP and a mechanical drive heat rate of 7490 Btu/hp-hr. Adjusting for
site conditions at approximately 20% loss, the horsepower equates to 12,000 HP with a
8900 Btu/hp-hr heat rate.
The Clark 272B 3/4 compressor has an efficiency of approximately 80% whereas new
compressors range from 84% to 86%.
5
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
6
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 4:
Has SoCal considered the use of a hybrid electric and gas system that would retain
some gas-fired compression for the specific purposes of replacing electric compression
during periods of peak electrical demand as well as for backup purposes? If so, please
provide any memoranda or other documentation of the results of such analysis or
consideration. If not, why not?
RESPONSE 4:
No, SoCalGas did not consider a hybrid electric and gas system that would retain some
gas-fired compression to replace electric driven compression during periods of peak
electrical demand. Retention of the existing gas turbines is not an option given that
those units are old, obsolete and could no longer be economically maintained.
Installation of a new gas-driven compression system that could support 145 mmcfd of
injection capacity during periods of peak electrical demand would be cost prohibitive as
it would require essentially a 100% back-up gas-driven compression system to avoid
the limited incremental cost of electricity during peak electrical demand periods.
Based on historical usage, the estimated annual On-Peak electric consumption would
be approximately 4,170 MWH (roughly 4.6% of the total annual electric consumption).
Were a gas-driven back-up system available, the equivalent gas consumption would be
approximately 45,630 MMBtu. A comparison of the energy cost for estimated On-peak
gas and electric consumption is as follows:
On-Peak Energy
Consumption
4,170 MWH
45,630 MMBtu
On-Peak
Energy Cost
$ 1,022,874
$ 273,787
D Cost $ 749,087
Gas cost evaluated at $6/MMBtu;
Electric cost evaluated at Critical Peak Pricing for Sub transmission level service
These annual energy cost savings would only support a capital investment in the range
of $5.0 million, which is far too small to install a new gas-fired back-up system capable
of the new injection capacity.
It should also be noted that during peak electrical demand periods SoCalGas’ storage
operations are normally operating in gas withdrawal mode and not in gas injection
mode. That is why historically less than five percent of Aliso Canyon’s gas injection has
incurred during On-peak electrical periods.
7
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 5:
Has SoCal Gas considered use of turboexpander or similar technology to capture
energy from the withdrawal of compressed gas from storage? If so, please provide any
memoranda or other documentation of the results of such analysis or consideration. If
not, why not?
RESPONSE 5:
No, this technology was not considered; therefore no memoranda or documentation
exists. The reasoning why this technology was not undertaken is explained below.
The Aliso Canyon Turbine Replacement Project is a gas compression project and does
not address gas withdrawal in any way. The project’s main objective is to replace the
obsolete LM1500 driven compressor trains that have been in service almost 40 years
and to increase injection capacity by at least 145 mmcfd.
However, field piping during withdrawal from the injection/withdrawal wells combines at
the inlet to the dehydration station. The pressure differential between the dehydration
process outlet and plant discharge pressure is less than 100 psig. With this small
pressure differential and a withdrawal duration averaged over the past three years of
less than 3000 hours/year, turboexpanders would be of little value. Capturing the
energy from the small pressure differential must then be converted to some useful
benefit such as mechanical drive or electric generation which further increases cost.
This benefit would only be available during withdrawal when plant energy requirements
are small.
8
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 6:
Please provide itemized estimates of the costs of the new compressor plant (e.g.,
materials, labor, contracts, overheads, etc.)
RESPONSE 6:
The major pieces of plant equipment within the Procurement category of the EPC
contract can be itemized as follows:
Major Plant Equipment*
Gas Compressor
Electric Motor
High Speed Gear Box
Lube Oil Console
Variable Frequency Drive
Seal Gas System
Coolers
Surge Control System
Additional Support Systems
Cost ($MM)
$
8.10
$
6.90
$
1.80
$
1.80
$
6.62
$
1.62
$
3.30
$
0.83
$
2.35
* Note the above costs are not escalated and do not account for the total Procurement cost estimate
The Construction category of the EPC contract accounts for materials, labor, and other
related fees, which can be described in more detail as follows:
Cost Element
Demolition
Site Improvement
Earthwork
Concrete
Structures
Pipe - Mat'l Installation
Electrical - Mat'l Installation
Instru & Controls - Bulks & Installation
Painting / Coating
Insulation
Buildings
Capital Spares
Labor
Materials
($MM)
($MM)
$
0.29 $
0.01
$
1.42 $
0.92
$
9.66 $
1.07
$ 10.91 $
2.12
$
0.59 $
0.89
$
5.97 $
3.62
$
4.48 $
6.77
$
0.56 $
1.97
$
0.10 $
0.01
$
0.08 $
0.02
$
0.26 $
0.47
$
$
0.98
9
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
RESPONSE 6 (continued):
Related Fees
Construction Management
Insurance
Bonds
Taxes
Freight
2 Year Operational Spares
Contractor Fees
Cost ($MM)
$
4.74
$
1.53
$
0.29
$
5.75
$
5.58
$
0.76
$
13.92
SoCalGas overhead is estimated to be $0.92 million.
10
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 7:
Please provide a discussion of the efficiency of the electric compression equipment that
SoCal proposes to use and any benefit-cost or cost-effectiveness analysis of the fuel
cost versus the capital cost of the option chosen by SoCal versus other options).
RESPONSE 7:
Electric motor drives are more efficient than the gas drive alternative (turbines) that was
being considered for the new Aliso Canyon compressors.
Option
EPC Cost Estimate*
Electric Motor
$156 MM
Gas Turbine
$176 MM
* Represents unescalated cost
The benefits of a lower capital cost and lower operating costs associated with the
electric motor option are partially offset by higher energy costs.
Taking into account these various factors, the overall economics favor the electric motor
option.
As referenced in Responses 1 & 3, gas turbine efficiency is rated at ISO and site
conditions. A gas turbine site rated at the same horsepower as the site rated electric
motor, 22,000 hp, would have approximately 32-35% thermal efficiency. A 22,000hp
electric motor would have an efficiency of 97-98%. However, taking into account the
thermal efficiency of the electricity generation to power the motor, approximately 3537%, the motor energy system and the gas turbine energy system are similar.
11
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 8:
Please provide the gross plant and depreciation reserve associated with the amounts
included in Accounts 354 and 351 expected at the time of retirement.
RESPONSE 8:
Account 351
The book life of assets in FERC account 351 is 37 years. At the end of 37 years, the
gross plant associated with amounts included in this account will equal the original
investment of $3.357 million.
The depreciation reserve will equal the original investment plus the net salvage value.
Net salvage value is 30% of the original investment. Therefore, the depreciation
reserve will equal $4.364 million.
$3.357 million + (30% x $3.357 million) = $4.364 million
At the expected time of retirement, the net plant balance will equal the net salvage
value.
Account 354
The book life of assets in FERC account 354 is 40 years. At the end of 40 years, the
gross plant associated with amounts included in this account will equal the original
investment of $197.557 million.
The depreciation reserve will equal the original investment plus the net salvage value.
Net salvage value is 5% of the original investment. Therefore, the depreciation reserve
will equal $207.435 million.
$197.557 million + (5% x $197.557 million) = $207.435 million
At the expected time of retirement, the net plant balance will equal the net salvage
value.
12
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 9:
Please provide detailed workpapers supporting the revenue requirement. Please
include data showing book and tax depreciation, assumed property tax rates, and
amounts of the new plant in Accounts 354 and 351.
RESPONSE 9:
See attached worksheets:
Aliso Compressor
Acct 351 9-11-09.xls
Aliso Compressor
Acct 354 9-11-09.xls
Aliso Compressor
Summary 9-11-09.xls
Capitalized
Maintenance Credit 9-10-09.xls
13
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 10:
Is there any reason to expect that electric compressors will have a shorter or longer life
than gas turbine compressors?
RESPONSE 10:
The compression trains have several components that are very similar. For turbine
driven, the train consists of a turbine, gear, centrifugal compressor and selective
catalytic reduction (SCR) units for controlling the turbine emission quality. For electric
driven, there is an electric motor, gear, centrifugal compressor and a variable frequency
drive (VFD) for controlling the motor. The electric motor or gas turbine is the driver that
provides power to a separate stand-alone centrifugal compressor. The life of the
compressor is independent of the drive source. The turbines require regular
maintenance and rebuilds that are proportional to hours of use and number of starts.
The lifespan of a typical turbine between zero hour rebuilds is approximately 30,000
hours. The turbine SCRs would also require catalyst replacement at intervals
dependent on number of fired hours. The electric motors have almost no maintenance,
but the motors would need replacement in 30-40 years and the VFDs would require
replacement every 15 to 20 years. The gear and compressor lifespan are not affected
by the type of driver used to power them; thus, the lifespan of these components are the
same for either driver option.
14
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 11:
Please provide detailed workpapers supporting Table 4 of the application, including but
not limited to (a) injection revenue requirement before the increases in revenue
requirement arising from the project in 2013-2017 and its allocation between core
storage, load balancing, and unbundled storage; and (b) the total revenue requirement
after the project and its allocation between core storage, load balancing, and unbundled
storage.
RESPONSE 11:
The figures in Table 4 are derived by applying the Post-Replacement capacities in
Table 3 to the Post-Replacement Injection Revenue Requirement. The PostReplacement Injection Revenue Requirement includes both (i) the revenue requirement
before the Project; and, (ii) the revenue requirement of the replacement project. The
amounts related solely to the replacement project are the difference between the PostProject and the Pre-Project amounts.
Injection Revenue Requirement for Year 1
$millions
(w/o FFU)
1
2
Post-Project
% of total
Core
$18.1
Load
Unbundled
Balancing
Storage
$9.3
$19.0
Total
$46.4
1
2
39.0%
20.1%
40.9%
100.0%
less Pre-Project
$10.3
$5.6
$7.8
$23.7
Project
$7.8
$3.8
$11.2
$22.8
3
4
3
5
6
4
5
15
6
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 12:
Please provide workpapers showing the derivation of the storage fuel in-kind factor on
page 19.
RESPONSE 12:
See attached worksheet.
alisofuelfinal.xlsm
16
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 13:
Please identify all costs associated with the gas turbines that are going to be replaced if
this application is approved that were included in the base year 2005 costs in Account
834 that formed the basis of SoCal’s 2008 GRC request for this account.
RESPONSE 13:
The base year 2005 costs in Account 834 of SoCal’s 2008 GRC are an aggregate of all
834 costs for SoCal’s storage activity. The costs applicable to the gas turbines are
$1,200,000.
17
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 14:
Will the installation of new compressors and increased inventory cause any changes in
oil production at Aliso Canyon? If so, please provide a description of any such changes.
RESPONSE 14:
No, the installation of new compressors will not cause any change in the oil production
at Aliso Canyon. This project will not increase gas storage inventory.
18
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 15:
What is the basis for SoCal’s estimate of $500,000 per year of capital maintenance for
the old compressors?
RESPONSE 15:
The historical capital maintenance expenses over the three year period from 2007 to
2009 were used as the basis for this estimate, as illustrated in the following table:
Year
Capital Spending
2007
$244,000
2008
$110,000
2009 (YTD)
$1,181,000
Average
$511,000
Note the 2009 capital spending total is a year to date figure.
19
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 16:
Have the compressor overhauls included in Exh. SCG-5 JMR-CWP-292 in SoCal’s
2008 GRC been completed? If not, why not?
RESPONSE 16:
Overhaul of Engine K26 was completed in 2007. A partial overhaul of Engine K25 was
completed in 1st quarter 2009. Based on the annual inspections of all units and run
hours, no overhauls were done in 2008.
20
SOUTHERN CALIFORNIA GAS COMPANY
APPLICATION TO AMEND ITS CERTIFICATE OF PUBLIC CONVENIENCE &
NECESSITY OF THE ALISO CANYON GAS STORAGE FACILITY
(A.09-09-020)
(1ST DATA REQUEST FROM TURN)
______________________________________________________________________
QUESTION 17:
What is the schedule for gas turbine compressor overhauls at Aliso Canyon? When
would additional overhauls be required but for the new electric system? Would any
overhauls prior to 2013 be eliminated if the new electric system is installed?
RESPONSE 17:
See SoCalGas plant Operation and Maintenance section in the Project Description
located in Appendix A of the CPCN Application. To make the maximum injection rate,
the units are scheduled for overhaul every few years to insure their availability and
reliability. With the inherent uncertainty of constructing projects of this magnitude, the
existing maintenance plan for the TDCs will not be altered at this time. As construction
progresses, the existing maintenance plan will be reevaluated to determine where
savings can be made by avoiding further overhauls. With the entire engineering,
procurement, and construction (EPC) process scheduled for 30 months or less, it is
likely that some maintenance can be avoided. Again, construction progress and the
condition of the TDCs in three years will determine any possible cost avoidances.
21