DoE Level VII (7): New Standards for US Energy Efficiency

The U.S. Department of Energy (DoE) regulations on power conversion efficiency have been enforced for many years to reduce energy consumption and lessen environmental impact. Currently, the standard is Level VI, but a new "Level VII" standard is scheduled to be introduced in the future.

Planned Transition of DoE Level from VI to VII

The U.S. Department of Energy (DOE) is planning to transition its efficiency regulations from the current Level VI to a more stringent Level VII.

The origin of these efficiency standards dates back to the 2007 Energy Independence and Security Act (EISA), which laid the foundation for energy-saving standards for external power supplies (EPS). The most recent version, Level VI, was published in 2014. Compared to 10 years ago, advancements in wide-bandgap technologies like silicon carbide and gallium nitride (GaN) have enabled the production of more efficient EPS, and since products using these technologies are now widespread in the market, there has been a movement to raise the efficiency standards accordingly.

Top 5 Differences Between DoE Level VI and Level VII

1: Expanded Scope of Efficiency Regulations

Level VII expands the scope of EPS coverage. While Level VI standards were limited to Class A direct operation EPS, Level VII introduces a unified standard that includes both Class A and non-Class A EPS, regardless of whether they operate directly or indirectly. This simplifies the regulatory application.

	Class A EPS	Non-Class A EPS
Direct Operation EPS	Level VI	Level VI
Indirect Operation EPS	Level IV	No standards

2: Differences in Marking and Compliance Protocols

The Level VI standard required efficiency marks with Roman numeral "VI" on EPS. In contrast, Level VII updates this protocol by introducing a new marking system that clearly indicates compliance with the latest Level VII standards.

3: Efficiency Requirements

DoE Level VII is designed to impose stricter restrictions on both operational efficiency and no-load power consumption, thereby promoting reduced energy usage.

(Single Output AC-DC Adapter - Basic Voltage)

Rated Output Power	Minimum Average Efficiency	Maximum No-Load Power Consumption
1W or less	0.5×Pout + 0.169	≤0.075W
Over 1W – 49W or less	0.071×ln(Pout) - 0.00115×Pout + 0.67	≤0.075W
Over 49W – 250W or less	89.0%	≤0.150W
Over 250W	89.0%	≤0.150W

(Single Output AC-DC Adapter – Low Voltage)

Rated Output Power	Minimum Average Efficiency	Maximum No-Load Power Consumption
1W or less	0.517×Pout + 0.091	≤0.075W
Over 1W – 49W or less	0.0834×ln(Pout) - 0.0011×Pout + 0.609	≤0.075W
Over 49W – 250W or less	88.0%	≤0.150W
Over 250W	88.0%	≤0.150W

(Multiple Output Power Supply)

Rated Output Power	Minimum Average Efficiency	Maximum No-Load Power Consumption
1W or less	0.497×Pout + 0.067	≤0.075W
Over 1W – 49W or less	0.0782×ln(Pout) - 0.0013×Pout + 0.643	≤0.075W
Over 49W – 250W or less	88.5%	≤0.150W
Over 250W	88.5%	≤0.150W

Note:

Pout represents rated output power (W).
Efficiency is shown as a decimal (e.g., 88.0% = 0.880).
Basic Voltage: Output voltage of 6V or higher.
Low Voltage: Output voltage below 6V.

5: Considerations for Adaptive EPS

For adaptive EPS such as USB-C and PD power supplies (which support multiple output voltages), there are ongoing discussions for setting different efficiency limits to reduce design burdens while improving efficiency. Especially for low output voltages (3.3V or 5V), more flexible efficiency standards are being considered.

Benefits of Introducing DoE Level VII

1: Reduced Operating Costs for End Users
Annual operating cost savings are estimated at approximately $47.3 million. Even with a 7% discount rate, savings of about $42.7 million per year are projected.

2: Environmental Benefits
Greenhouse gas reduction benefits are estimated at approximately $11.5 million annually, contributing positively to climate change efforts. These estimates are based on a 3% discount rate for calculating the social cost of carbon reduction.

3: Health Benefits

Reductions in harmful emissions such as SO₂ and NOₓ are expected to result in annual health-related benefits valued between $16.7 million and $20.4 million. Especially, reducing precursors of PM2.5 is believed to offer significant health advantages.

Based on these figures, the adoption of Level VII standards is expected to bring substantial economic, environmental, and health benefits.

Final Announcement and Preparation Period for the New Standards

The final rule for the Level VII standards is scheduled to be announced in the second half of 2024. Following the announcement, a two-year preparation period for compliance will be provided, consistent with previous energy conservation regulations. At Unifive, we already offer a lineup of products compatible with the draft DoE Level VII standards.

For the latest information, please feel free to contact our sales team.