1. Natural Esters Mineral Oil Replacement
NWPPA
4/11/2016 Chip Bloomer Senior Project Specialist Environmental Compliance & Licensing
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2. 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)

3. 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?

4. 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

5. 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

6. 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

7. Cost
New Transformer
Slight Adder
Trending Lower
Maintenance Equipment

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

9. Negatives & Unknowns
Polymerization
Recover/Disposal

10. Questons?