Natural Esters Mineral Oil Replacement NWPPA 4/11/2016 Chip Bloomer Senior Project Specialist Environmental Compliance & Licensing Subhead about the topic Date etc. Presented by: any additional information here

Portland General Electric 842,000 customers 2,600 employees Service territory population 1.8 million, 45% of state’s population 52 cities served 4,000-square-mile service area 1,200 miles of transmission lines 3,414 MW of generation Summer peak load of 3,950 MW (2009) Winter peak load of 4,073 MW (1998) 190,000 distribution transformers ~180 substations Last Updated: March 2015 (Quick Facts)

Overview Drivers Operational Benefits Environmental Benefits Cost - Availability Negatives and Unknowns Advantages of natural esters including biodegradability, fire resistance and longer transformer life. higher first cost?

Drivers Drivers Push From Outside Environmental Group PCB Elimination Program Evaluation of distribution transformers Risk and Liability analysis – No future liability Already Using In Some Areas O8 Transformer Shop, Purchasing, Distribution Standards Engineering

Operational Benefits Safety Reliability Flash Point Solubility Conventional mineral oil has a flash point of 145°C while natural esters have a flash point from 330 to 360°C. Factory Mutual Insurance Company (Factory Mutual) has stated that using approved ester-based insulating fluid, water spray protection and barriers are not needed if minimum spacing is provided. Research also shows that natural ester insulated transformers age more slowly than those insulated with mineral oil. Paper insulation in transformers deteriorates (loses tensile strength) over time due to water which can eventually lead to transformer failure. This is largely due to the greater solubility of water in ester oils, which draws moisture out of the cellulose insulation thereby reducing the cellulose aging rate. Relative accelerated aging study of new thermally upgraded cellulose paper

Environmental Benefits Edible Biodegradability Not Regulated in Oregon No state spill reporting No clean up standards No Risk Based Concentrations Ester dielectric oils are completely miscible with mineral oils and most standard transformers require no mechanical modications in order to be retrofilled with the fluid There are no Risk based Concentration screening levels

Cost New Transformer Slight Adder Trending Lower Maintenance Equipment

Implementation Backfilled Inventory Not Retro Filling Mineral Oil Transformers Designated Recovery Equipment

Negatives & Unknowns Polymerization Recover/Disposal

Questons?