New Federal Battery Charger Efficiency Standards Will Power America’s Mobility without Costing the Earth

Update 6/13/2016: The effective date of the standards was updated to June 13, 2018, per DOE’s notice of final rule published on the Federal Register on June 13, 2016.

The Department of Energy is to be congratulated for setting efficiency standards for the nation’s 2 billion-plus electrical chargers that America’s consumers and businesses rely on every day to keep our mobile society moving. The Natural Resources Defense Council has been a principal advocate for these standards for years.


More than 500 million of these chargers (those little bricks on the power cord of products with rechargeable batteries) are sold every year and there already are an estimated 2 billion in use in American homes and businesses. They keep our cell phones, laptops alive, our other electronic widgets juiced up, our power tools ready for use, and even those drones up in the air and hover boards rolling. Screwdrivers, drills, vacuum cleaners and more all can be ordered “to go” thanks to these rechargeable batteries.

These new DOE standards address the battery charger system part of portable products that typically includes: the power supply unit that plugs into an outlet, the battery that is being charged, and the charge control circuitry that is often integrated into the product.

Small devices, big savings

The DOE’s new standards, released in May and formally published in the Federal Register on June 13, are designed to make chargers more efficient by just over 10 percent on average when they go into effect on June 13 2018, saving 500 million kilowatt-hours annually, enough electricity to power all the households in a city of 100,000 people.

However, this is just the tip of the iceberg: national savings are roughly 30 times as high, or 18 billion kilowatt-hours, when accounting for California’s existing battery charger standards that have been in effect since 2013 and whose effects were felt far beyond the Golden State’s borders. In fact, DOE estimates that 95 percent of all products sold on the U.S. market now comply with California requirements. State and federal standards combined will save enough electricity annually as the output of six large (500-megawatt) coal-fired power plants.

DOE’s new standards mostly mirror California’s and extend them to the rest of the country, ensuring all products sold in America are designed to waste less energy, and locking-in the financial, health, and environmental benefits driven by the original state standards. The new federal standards mirror California’s for most products, and even improve them for a few product types such as electric toothbrushes and golf cars.

Until the DOE’s standards, there had been only two states, California and Oregon, that had acted on concerns about the energy wasted to keep mobile product batteries charged, such as when continuing to pump current into fully charged batteries for lack of charge control, or when charge control circuits draw much higher vampire loads than necessary.

While some of the smaller individual devices, like cordless phones and cell phones, require only a small amount of electricity to achieve a full charge, the fact that there are more than two billion such devices nationwide—between 15 and 20 per household—being powered up daily constitutes a substantial drain on the grid.

Missed opportunities

While these new federal standards are a good step toward reducing unnecessary energy waste by inefficient products, DOE missed some opportunities to cut even more energy waste.

First, DOE could have doubled savings from these new federal standards to more than 1 billion kilowatt-hours annually by raising the bar for cell phone chargers. DOE’s own analysis showed that tighter levels would have been cost-effective overall for these products, but it chose not to because while these higher levels would have been cost-effective overall, they would have cost more than they would have saved for certain applications.

Second, DOE decided to temporarily exclude battery backup systems (such as uninterruptible power supplies or UPS), a sub-category of battery chargers, from the rule, while still defining them as battery chargers. This will preempt existing state standards for UPSs when the federal standards take effect in 2018. DOE recently published a separate test procedure proposal for battery backup systems, and may then set standards for these products. During the period between May 2018 and new federal battery backup systems standards become effective, these products will no longer be covered by either state or federal efficiency standards. This could lead to a loss of savings if manufacturers take advantage of this situation. While the risk of significant regression may be low if the non-coverage period is short, we urge DOE to proceed swiftly and finalize these battery backup system standards as soon as possible.

Despite these missed opportunities, the DOE’s new standards will ensure the industry keeps energy efficiency in mind when designing and producing products for our portable world. That world will only expand in the future, and these standards create a framework that not only will allow that expansion, but also be energy efficient.

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