DOE Standards for Distribution Transformers Would Cut Electricity Waste, Climate Pollution

Contact: Mark Rodeffer, 202-507-4018,  

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Washington, DC—A U.S. energy efficiency standard proposed today for new distribution transformers—a familiar sight on utility poles—would cut greenhouse gas emissions significantly by reducing electricity lost on the way to homes and businesses. The plan from the Department of Energy (DOE) would avert 340 million metric tons of carbon emissions and save $15 billion over the next 30 years—savings that should largely be passed on to electric customers.

Nearly all electricity generated at power plants goes through one or more transformers, so even small efficiency improvements can significantly reduce electricity production and thus greenhouse gas emissions from power plants.

“Most distribution transformers today use outdated technology that wastes electricity before it even gets to our homes and businesses. This standard would ensure all new models minimize waste and use materials with a robust long-term supply,” said Andrew deLaski, executive director of the Appliance Standards Awareness Project. “Just this small efficiency improvement would avert significant greenhouse gas emissions because these things are everywhere.”

The primary function of distribution transformers is to change the voltage of distributed electricity. For example, transformers reduce electricity voltages from the levels used to send power over transmission and local distribution lines to the lower levels used to power homes, businesses, and industry. The new proposal would update standards for both “liquid-immersed” models (found outdoors, e.g., on utility poles or concrete pads, and owned by utilities) and “dry-type” models (generally installed indoors and owned by building owners).

Standards for both types were last updated in 2013, but that change required only minimal improvement.

Transformers essentially consist of an electrical steel core surrounded by copper or aluminum windings. The cores of transformers meeting the new standards would almost certainly use a material called amorphous steel, a proven technology that has been used in more-efficient transformers in the United States since the early 1990s. Still underutilized in this country, it is widely used in distribution transformers in China and India.

DOE’s proposal presents compelling evidence that the supply of the amorphous steel used in the more efficient transformers will be both stable and reliable. Growing demand for electric vehicles, which use electrical steel in their motors, has constrained supply for the less efficient, conventional electrical steel now typically used in transformers. Shifting transformers to amorphous steel, which is not used in electric vehicle motors, would reduce this supply constraint.

Under federal law, DOE was supposed to propose new distribution transformer standards by 2019 and finalize them by 2021. If finalized, the new standards would take effect in 2027.


The Appliance Standards Awareness Project (ASAP) organizes and leads a broad-based coalition effort that works to advance, win and defend new appliance, equipment and lighting standards that cut emissions that contribute to climate change and other environmental and public health harms, save water, and reduce economic and environmental burdens for low- and moderate-income households.