January 2012 Capital Investment - National Grid

Exhibit ___ (EIOP-19)Page 109 of 684Mobile SubstationMobile substations are key elements for ensuring continued reliability and supporting thesystem during serious incidents. This program was listed under the System Capacityand Performance spending rationale in the 2011 CIP.Drivers:In order to improve the management of the mobile substation fleet, the Companyconducted a review which considered system requirements, the amount of mobileusage, and the uniqueness of the individual unit to better understand the condition of allmembers of the fleet and their associated risks. Highly utilized units may present a riskif they are not properly maintained or refurbished. Further, uniquely configured units orvery highly utilized units in which there is only one available unit on the system, presentsome risk since they may not be available for an emergency due to utilization elsewhere.Based on the review, mobile substation protection upgrades, rewinds and replacementunits were recommended.Customer Benefits:A mobile substation or transformer is the quickest method for restoring service tocustomers when an outage occurs in a substation, typically occurring within sixteen totwenty-four hours. By refurbishing, upgrading, replacing and purchasing new mobilesubstations, as necessary, via system reviews and condition assessments, the risk ofextended customer outages will be significantly reduced. In addition, properlyaddressing the needs of the mobile fleet will allow us to schedule maintenance forsubstation transformers in a timely manner since they are one of the most valuableassets on the system. Lastly, having an adequate number of mobile substations onhand will promote the completion of new construction projects on-time and on-budget.2011 to 2012 Variance:The projected investment is shown in the table below. The revised plan is based onidentified work related to the strategy.Table IV-25Mobile SubstationProgram Variance ($millions)CIP FY12 FY13 FY14 FY15 FY16 FY17 Total2011 1.0 2.0 2.0 2.0 2.0 - 9.12012 - 1.7 1.0 1.1 1.1 - 4.8Within this program, there is one specific project identified that exceeds $1 million in anyfiscal year:• Project Candidate, New NY Mobile Substation 69-13.8x4.8x4.16kV - A highlyutilized mobile substation has been identified in the eastern region of New Yorkas a new system requirement to sustain our emergency and maintenance needsby providing additional coverage for 30 substations.IV-33 33110