Transmission and Distribution Loss Study Virgin Islands Water and Power Authority June 2008

Purpose Quantify T&D facility losses using available tools Provide a basis for recommendations to reduce T&D system losses Prioritize recommendations based on impact to T&D losses

Results of Loss Study - St. Thomas FY 2007

Results of Loss Study – St. Croix FY 2007

Results of Loss Study FY 2007 System Statistics Type STT STX Cost of Power (1) ($/kWh) $0.164 $0.195 Annual Cost of Losses (2) ($/peak kW) $817.51 $1,032.71 Transmission (mi) 30 N/A Distribution (mi) 339 479 Number of Customers 32,369 25,839 System Peak (MW) 88.1 54.1 Notes: (1) Based on fuel costs for FY 2007, only. (2) Calculated costs of losses based on cost of power for FY 2007.

Basis of Analysis & Assumptions Engineering models of T&D system loads at FY 2007 peak FY 2007 system energy & peak demand, and financial statistics VIWAPA and industry standards Cost of losses based on FY 2007 fuel cost only Customer load based on transformer size Secondary lengths and types based on averages Load factors per customer class based on 2007 system load factor

Strategies to Reduce T&D Losses Support, maintain, and upgrade engineering models Standardize distribution transformer sizing for more efficient use of capacity Increase maintenance practices Use economic analysis to select conductors for construction, upgrades, and conductor replacement program

Strategies to Reduce T&D Losses Implement new DOE Transformer Efficiency Standards GPS inventory of system facilities Improve voltage regulation on T&D systems Add proposed substation for St. Croix Add line regulation as interim solution for proposed substation Accelerate tree trimming program Increase infrared camera inspections

Strategies to Reduce Other System Losses Improve QA/QC of collected metering data Ensure billing processes are timely and accurate Implement Automated Meter Reading (AMR) system-wide Without AMR: Accelerate meter calibration program Continue focus on meter resealing and meter lock ring programs Reconcile unmetered lighting accounts Field verification of light operation