Efficiency Standards History: Materials related to the 1997 determination are on DOE’s determination analysis webpage.

Under contract to DOE, LBNL’s Energy Efficiency Standards (EES) group conducted analysis for distribution transformers starting in 2000. On November 1, 2000, DOE held a public meeting to present and discuss its Framework Document.

In July, 2004, DOE published its advance notice of proposed rulemaking (ANOPR) in the Federal Register and posted the ANOPR and the ANOPR technical support document (TSD) on its distribution transformers website. The spreadsheet models used in the analyses are available on the ANOPR analytical spreadsheets webpage.

DOE conducted a public meeting to discuss the ANOPR on September 28, 2004. Presentation materials from the meeting are available on the ANOPR public meeting webpage.

DOE published the notice of proposed rulemaking (NOPR) on August 4, 2006, and posted the NOPR TSD and supporting analytical spreadsheet models on its NOPR webpage shortly thereafter. DOE held the public meeting for the NOPR on September 27, 2006.

On February 9, 2007, DOE published a notice of data availability, which described methods for addressing size constraint issues.

In October, 2007, DOE published the final rule and posted both the TSD and analytical spreadsheet models that support this final rule on its final rule webpage.

Product Description and Usage: Electrical energy is passed through distribution transformers to lower high voltage levels on distribution lines down to end-use levels. Nearly all energy used in the United States passes through at least one distribution transformer before being consumed by an end-use appliance, motor, or other piece of equipment. Transformers are found in all sectors of the economy: residential, commercial, and industrial.

Technology: Distribution transformers are generally categorized in several ways:

· type of insulation: liquid-immersed or dry-type;

· number of phases: single-phase or three-phase;

· voltage class (for dry-type): low or medium; and

· basic impulse insulation level (BIL), for medium-voltage, dry-type.

Basic impulse insulation level, or BIL, is a technical concept important in the construction of medium-voltage, dry-type transformers. Most liquid-immersed distribution transformers tend to be built for similar BIL levels and so BIL does not result in different product classes within the category of liquid-immersed transformers.

Efficiency Rating: Distribution transformer efficiency is measured as the ratio of the power output to the power input. Efficiency is a function of the load on the transformer, and the DOE test procedure evaluates efficiency at a loading level of 50% rated capacity for medium-voltage transformers, and at a loading level of 35% of rated capacity for low-voltage transformers. Typical distribution transformer efficiencies are in the range of 97% to 99.5%, depending on the size of the transformer.

Product Classes: DOE’s final rule considered this set of eight product classes for the types of distribution transformers subject to the rulemaking. (The final rule did not consider two other product classes originally included in the rulemaking—low-voltage, single-phase, dry-type and low-voltage, three-phase, dry-type—since EPACT 2005 established energy conservation standards for these two product classes.)

· liquid-immersed, single-phase

· liquid-immersed, three-phase

· dry-type, single-phase, medium-voltage, low BIL

· dry-type, three-phase, medium-voltage, low BIL

· dry-type, single-phase, medium-voltage, medium BIL

· dry-type, three-phase, medium-voltage, medium BIL

· dry-type, single-phase, medium-voltage, high BIL

· dry-type, three-phase, medium-voltage, high BIL

Analyses: Under contract to DOE, LBNL's Energy Efficiency Standards (EES) group conducted analysis for the ANOPR, the NOPR, and the final rule, including:

· Markups for Equipment Price Determination

· Energy Use and End-Use Load Characterization

· Life-Cycle Cost and Payback Period Analysis

· Shipments Analysis

· Employment Impact Analysis

· National Impact Analysis (National Energy Savings and Net Present Value)

· Net National Employment Impact

· Utility Impact Analysis

· Environmental Assessment

· Regulatory Impact Analysis