Hitachi Energy’s transformers with low-carbon copper to support TenneT Germany’s supply-chain decarbonization program

As part of a framework agreement (FA) with TenneT Germany signed in 2023, Hitachi Energy has manufactured and delivered its first power transformer (380 megavolt-ampere (MVA)) with low-carbon copper to a substation in Hardebek, a municipality in Hamburg, Germany. All units under this agreement will be deployed with low-carbon copper conductors. With this, Hitachi Energy is actively supporting TenneT’s ambitious climate commitments. TenneT Germany is the largest transmission system operator in Germany. The company aims to reduce carbon emissions by 30 percent by 2030 (compared to 2019), as outlined in the company’s program.¹

The low-carbon copper conductor reduces embedded carbon emissions in transformer materials by 18 percent.² The anticipated total reduction across all transformer units under this frame agreement – currently at various stages of engineering and manufacturing – adds up to an estimated 9,500 metric tons of carbon emissions for TenneT. To achieve the same emission savings on the European electricity grid, approximately 24 megawatt (MW) of installed wind capacity operating for one year would be required.³

One of the first metals ever used by humans was copper, dating back over 10,000 years. While used for decorative items, weapons, and tools back then, the versatile metal is now essential for electrical wiring, plumbing, and electronics. In transformers, copper is mainly used as a conductor in the winding, chosen for its superior electrical and thermal conductivity. It helps maintain safe temperatures, prevents insulation damage, and withstands mechanical stresses, all contributing to the reliability and longevity of transformers. 

Copper mining and processing are resource-intensive, making copper conductors a significant contributor to the “cradle-to-gate” environmental footprint of transformers. Adopting low-carbon copper in a transformer reduces the overall environmental impact costs from material use by 60 percent, as measured by TenneT’s Environmental Cost Indicator (ECI) methodology.⁴

According to the GHG protocol, GHG emissions can be classified into three scopes:  

• Scope 1: Direct emissions from owned/controlled sources (e.g., company vehicles, emissions from fossil fuel combustion on-site) 
• Scope 2: Indirect emissions from purchased and consumed energy (electricity, heat) 
• Scope 3: All other indirect emissions in the value chain (e.g., procured goods and services, capital goods, use of sold products) 

Over the last few years, TSOs have substantially reduced their GHG Scope 2 emissions, partly thanks to highly efficient power transformers and an increasingly renewable-powered European energy mix. But as the demand for new transformers grows, TSOs face increased Scope 3 emissions from procured capital goods. Decarbonizing the material supply chain is therefore the most effective instrument for reducing GHG Scope 3 emissions and meeting climate commitments to a net-zero⁵ electricity future.