2.0 PROJECT JUSTIFICATION 2.1 JUSTIFICATION

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1 2.0 PROJECT JUSTIFICATION 2.1 JUSTIFICATION The principal justification for the proposed upgrade of CS-2B is to replace equipment that is near the end of its service life and which poses the greatest compression reliability risk to the Southern Mainline System. Westcoast undertakes periodic risk analysis and reviews of system reliability. CS-2B was identified as the next critical station in the Southern Mainline System requiring a compressor unit and utility system upgrade to replace equipment that is near or at the end of its useful service life. It is a continuation of a program that began in 1994/1995 with installations at CS-4A, CS-4B and CS-5 and again in 2002/2003 with installation of units at CS-6A and CS Reliability and Maintenance CS-2B has one Westinghouse W92 gas turbine engine and one Cooper Coberra (SPEY ) 3045 gas turbine engine both with a DeLaval PV 30 x 30 centrifugal compressor operating in series. The Westinghouse W92 gas turbine engine is capable of providing 8.3 megawatts (MW) of rated power. It was installed at CS-2B in 1968 and is an obsolete piece of equipment which is nearing the end of its service life. After the LM200 compressor unit is put into service, the W92 will be operated only on a standby basis and will eventually be retired. Westcoast will file the appropriate application for the decommissioning of the W92 unit at that time. The Cooper Coberra (SPEY-1900) engine was installed in 1982 and is capable of providing 12.0 MW of rated power. The Cooper Coberra (SPEY-1900) is currently in reasonable operating condition but the manufacturer stopped producing these engines in excess of 20 years ago and hence, only minimal support is provided by the manufacturer. The proposed installation of the Nuovo Pignone LM2000 compressor unit at CS-2B will provide sufficient power to meet the compression requirements for non-peak day gas throughputs. This will result in reduced run time for the Cooper Westcoast Energy Inc., a Duke Energy company: Compressor Station 2B Upgrade Page 2-1

2 Coberra compressor unit, as it will primarily be operated during peak day gas throughput. The expectation is that the reduced run time for the Cooper Coberra unit will extend its expected service life beyond the year Replacement Parts Sourcing of replacement parts for the existing compressor units at CS-2B creates both a maintenance issue and an increased reliability risk for the Southern Mainline System. Due to the age of the existing units in service, obtaining replacement parts has become increasingly difficult. In the case of the Westinghouse W92, this unit is also no longer manufactured; however, because it is an industrial unit, a higher percentage of the components can be repaired as compared to Spey components. To maintain these units, Westcoast has had to source spare parts from units that have been taken out of service and from third party brokers. Westcoast has also developed and supports repair schemes and procedures. As mentioned above, the manufacturer of the Spey 1900 gas generator (engine) stopped producing this engine in excess of 20 years ago. Four gas pipeline and power generation companies still operate these engines, including other operating companies within DEGT. This has resulted in a severe world-wide shortage of spare parts which exacerbates the repair of components in this style of engine. Also, this style of engine has a defined life span and Westcoast s Spey fleet is approaching this defined life. Compressor Unit Shutdowns Compressor units shut down in response to variations in throughput, planned shutdowns for maintenance purposes and emergency shutdowns in response to unplanned incidents. After the upgrade, the number of compressor unit shutdowns at CS-2B will be reduced for the following reasons: Westcoast Energy Inc., a Duke Energy company: Compressor Station 2B Upgrade Page 2-2

3 (i) the new LM2000 compressor unit will have a wider operating flow range than the existing units at CS-2B; therefore, fewer unit start-ups/shutdowns will be required. (ii) The new gas turbine engine will typically operate more reliably than the existing units and therefore will shut down less often Operating Efficiency The new LM2000 compressor unit operates more efficiently than the other units in operation at CS-2B. The fuel consumption of the LM2000 unit is estimated to average MJ/KW-Hr versus the estimated fuel consumption of MJ/KW-Hr for the Westinghouse Gas Turbine unit it will replace. The fuel savings attributable to the installation of the LM2000 unit is currently estimated to be 3.31 MMscf/d at CS- 2B, based on peak day loading Environmental Benefits Air Emissions Methane Gas Methane emissions vary from year-to-year depending upon the number of compressor blowdowns required for each unit. Blowdowns are defined as the venting or blow down of high-pressure gas in order to de-pressurize a compressor unit. When these blowdowns occur, methane gas is vented into the atmosphere. There will be fewer blowdowns because: (i) the Westinghouse W92 and Cooper Coberra (Spey-1900) compressor units were designed and are operated to automatically de-pressure for any type of shutdown. The new LM2000 compressor unit has been designed to remain pressurized for all shutdowns except emergency and planned maintenance Westcoast Energy Inc., a Duke Energy company: Compressor Station 2B Upgrade Page 2-3

4 station shutdowns and/or other unit shutdowns where the station operator has evaluated the situation and has deemed it necessary; and (ii) the new LM2000 unit will prove to be more reliable. The overall result will be fewer blowdowns and a corresponding reduction in methane emissions. NO x and Other Potential Air Contaminants With the installation of the new LM2000 compressor unit and assuming 365 days per year operation, the net annual reduction in emissions of oxides of nitrogen (NO x ) is 59 tonnes per annum (-23%). Atmospheric dispersion modelling demonstrates there will be a commensurate drop in concentrations of nitrogen dioxide (NO 2 ) in ambient air near the facilities. The maximum predicted one-hour concentration of NO 2, even when added to the maximum historic values of NO 2, will still equal approximately two-thirds of the most stringent Federal 1 objective for NO 2 in ambient air. The discharge of oxides of nitrogen at the site poses minimal risks to human health and to the environment. It has also been concluded that there are insufficient quantities of other potential air contaminants emitted by the LM2000 unit to be of concern in the ambient environment. These substances include carbon monoxide (CO), fine particulate matter (PM 2.5 ), volatile organic compounds (VOC), sulphur dioxide (SO 2 ) and formaldehyde. 1 In Canada, the federal government has established a series of national ambient air quality objectives for NO2. There are three levels of objectives maximum desirable, maximum acceptable, and maximum tolerable. The maximum desirable objective is the most stringent. The current federal objective values for NO 2, the principal contaminant of concern, are summarized in Table No. 1. Federal or provincial objectives have been established for NO x (refer to the Environmental Assessment which is attached to this application as Appendix IV) TABLE 1 - Summary of Federal Ambient NO 2Air Quality Objectives Contaminant Averaging Period Maximum Desirable Objective (?g/m 3 ) Maximum Acceptable Objective (?g/m 3 ) NO 2 1- hour hour Annual arithmetic mean Westcoast Energy Inc., a Duke Energy company: Compressor Station 2B Upgrade Page 2-4

5 A detailed Dispersion Modeling Report by Levelton Engineering Ltd., comparing the predicted NO 2 concentrations both for the existing and proposed new equipment at CS-2B, is contained within Appendix A of the Environmental Assessment attached to this application as Appendix IV. This report was commissioned in 2001 for the Southern Mainline Expansion project but is still applicable since the CS-2B station configuration has not changed since that time. Noise Emissions The current noise level emitted from CS-2B will not be exceeded through a combination of noise reduction panels in the new building walls, an acoustic enclosure for the LM2000 compressor turbine, residential style turbine exhaust, and air intake and vent silencers. In the Province of British Columbia, the only environmental noise standards are those enacted by municipalities. As a result, Westcoast has adopted the requirements of the Alberta Energy and Utilities Board ("AEUB") Noise Control Directive (ID 99-08) with respect to the regulation of noise generated by energy facilities like CS-2B. Additional information concerning noise emissions is provided in the Environmental Assessment attached to this application as Appendix IV. Westcoast Energy Inc., a Duke Energy company: Compressor Station 2B Upgrade Page 2-5