Steel cores central in DOE’s transformer energy efficiency proposal

The US Department of Energy (DOE) has proposed new energy efficiency standards for distribution transformers. Almost all transformers produced under the new standard would feature amorphous steel cores that are, according to the DOE, significantly more energy efficient than those made of traditional, grain-oriented electrical steel.

The aim of the DOEs proposal is to improve grid resiliency, lower utility bills and reduce domestic carbon-dioxide emissions. If adopted within DOE’s proposed timeframe, the new rule will come into effect in 2027.  

“The Biden-Harris Administration continues to use every means available to reduce America’s carbon footprint while strengthening our security posture and lowering energy costs,” said US Secretary of Energy Jennifer M. Granholm.

“Efficient distribution transformers enhance the resilience of our nation’s energy grid and make it possible to deliver affordable electrical power to consumers in every corner of America. By modernising their energy-conservation standards, we’re ensuring that this critical component of our electricity system operates as efficiently and inexpensively as possible.” 

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Transforming the transformer

Current US efficiency standards apply to liquid-immersed, low voltage dry-type and medium voltage dry-type distribution transformers. DOE’s proposed rule would amend the energy conservation standards for all three categories. 

DOE estimates that the proposed standards, if finalised, would reduce US CO2 emissions by 340 million metric tons over the next 30 years — an amount roughly equal to the annual emissions of 90 coal-fired power plants. DOE also expects the proposed rule to generate over 10 quads of energy savings and approximately $15 billion in savings to the nation from 30 years of shipments.

Additionally, as the supply of traditional, grain-oriented steel tightens, DOE is focused on diversifying domestic steel production where capacity can be expanded, such as in the production of amorphous steel used in advanced transformers.

In support of these efforts, DOE is also finalising the implementation guidance for the distribution transformer and extended product system rebate programmes established by the Energy Act of 2020 and funded by President Biden’s Bipartisan Infrastructure Law.

This rebate programme encourages the replacement of energy-inefficient distribution transformers and extended product systems with more-efficient replacements.