What are the Energy Efficiency levels mandated by DOE as of January 1st 2016?

Frequently Asked Questions Distribution Transformers 

The US Department of Energy (DOE) has regulated the energy efficiency level of low-voltage (LV) dry-type distribution transformers in US since 2007, and liquid-immersed and medium-voltage (MV) dry-type distribution transformers since 2010.

DOE’s CFR (Code of Federal Regulation) title 10, part 431 defines the current energy efficiency standards for distribution transformers sold in US also known as TP1 energy efficiency levels as adopted by NEMA. Effective Jan. 1st 2016 DOE’s CFR 10 p.431 will require new higher levels of Energy Efficiency for transformers installed in any US territory as published in the Federal Register Vol. 78, No. 75 on April 18, 2013.

Any Distribution transformer manufactured on or after Jan. 1st 2016 and sold in any US state will have to comply with the new energy efficiency levels defined by this document.

Q2: What are the types of transformers affected?

The three types of distribution transformers covered by the standard are: low-voltage dry-type, liquid-immersed, and medium-voltage dry-type distribution transformers.

Q3: What are the Energy Efficiency levels mandated by DOE as of January 1st 2016?

The new Energy Efficiency levels mandated as of Jan.1st 2016 are as follows:

Amended Energy Conservation Standards for Low-Voltage Dry-Type Distribution Transformers

Single phase   Three phase  
kVA Efficiency (%) kVA Efficiency (%)
15 97.7 15 97.89
25 98 30 98.23
37.5 98.2 45 98.4
50 98.3 75 98.6
75 98.5 112.5 98.74
100 98.6 150 98.83
167 98.7 225 98.94
250 98.8 300 99.02
333 98.9 500 99.14
    750 99.23
    1000 99.28
Note: All efficiency values are at 35 percent of nameplate-rated load, determined according to the DOE Test Method for Measuring the Energy Consumption of Distribution Transformers under Appendix A to Subpart K of 10 CFR part 431.

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Amended Energy Conservation Standards for Medium-Voltage Dry-Type Distribution Transformers

Single phase       Three phase      
BIL* kVA 20–45 kV efficiency (%) 46–95 kV efficiency (%) 96 kV efficiency (%) BIL kVA 20–45 kV efficiency (%) 46–95 kV efficiency (%) 96 kV efficiency (%
15 98.1 97.86 – 15 97.5 97.18 –
25 98.33 98.12 – 30 97.9 97.63 –
37.5 98.49 98.3 – 45 98.1 97.86 –
50 98.6 98.42 – 75 98.33 98.13 –
75 98.73 98.57 98.53 112.5 98.52 98.36 –
100 98.82 98.67 98.63 150 98.65 98.51 –
167 98.96 98.83 98.8 225 98.82 98.69 98.57
250 99.07 98.95 98.91 300 98.93 98.81 98.69
333 99.14 99.03 98.99 500 99.09 98.99 98.89
500 99.22 99.12 99.09 750 99.21 99.12 99.02
667 99.27 99.18 99.15 1000 99.28 99.2 99.11
833 99.31 99.23 99.2 1500 99.37 99.3 99.21
        2000 99.43 99.36 99.28

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        2500 99.47 99.41 99.33
BIL means basic impulse insulation level              
Note: All efficiency values are at 50 percent of nameplate rated load, determined according to the DOE Test Method for Measuring the Energy Consumption of Distribution Transformers under Appendix A to Subpart K of 10 CFR part 431.

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