Decarbonization of the electricity grid depends on materials, suppliers, and infrastructure choices that remain largely invisible.
By Ankush Kumar
Renewable electricity appears clean when it reaches consumers. But the grid behind it is far more carbon-intensive than it seems. High-voltage lines, substations, and transformers rely on large volumes of steel and copper—materials that carry significant carbon emissions long before electricity begins to flow.
For TenneT, the operator connecting Germany and the Netherlands, this hidden carbon footprint is becoming central to strategy. The company does not generate electricity; instead, it transports it across borders and connects offshore wind, solar, and conventional power to millions of users.
As a result, TenneT sits at the center of Europe’s energy transition. At the same time, it faces a structural challenge. Germany is targeting climate neutrality by 2045 and deep emissions cuts by 2030. Therefore, the grid must expand rapidly to support rising renewable energy flows. However, expansion also increases carbon emissions unless supply chains change.
To address this, TenneT focuses on emissions beyond its direct operations. Most carbon linked to the grid sits in Scope 3—covering transformers, cables, steel structures, construction, and raw materials. In practice, these supply chain emissions dominate the grid’s overall carbon footprint.
More broadly, this reflects a wider reality. Grid operators cannot decarbonize through internal efficiency alone. Instead, carbon remains embedded in the industrial systems that build the grid itself.
Where the grid becomes carbon-intensive
Transformers sit at the heart of this challenge. They are among the most material-intensive assets in the electricity grid. They regulate voltage, allowing power to travel efficiently over long distances before being stepped down for industrial and household use.
In transmission networks, these units are massive. A single transformer can weigh hundreds of tons and contains large quantities of copper, steel, and insulating materials. Consequently, manufacturing them requires energy-intensive industrial processes that carry a substantial carbon footprint.
Copper remains the most critical input. Each unit contains several tons, and its production is highly carbon-intensive, particularly when fossil fuels power mining and refining. Similarly, steel production adds significant carbon emissions.
As renewable capacity expands, demand for these materials is rising sharply. Therefore, the embedded carbon in grid infrastructure is becoming increasingly important.
In response, TenneT is working closely with suppliers such as Hitachi Energy, which manufactures high-voltage equipment globally. The company is now introducing transformers that incorporate lower-carbon copper, including recycled and more sustainably produced material streams.
Importantly, the goal is not to change how transformers operate. Instead, the focus is on reducing the carbon embedded in their production.
At scale, the impact becomes meaningful. A single transformer has limited effect. However, when deployed across the grid, incremental improvements in materials can significantly reduce total carbon emissions. TenneT states that it emphasizes assessing assets across their full lifecycle, rather than focusing only on operational emissions.
Expanding the grid without raising carbon
Meanwhile, Germany’s energy transition is placing increasing pressure on the grid. Offshore wind from the North Sea must travel long distances to industrial regions in the south. At the same time, solar output fluctuates, and electrification of transport and heating continues to raise demand.
As a result, TenneT is expanding the grid at pace. New transmission corridors, substations, and converter stations are under construction. Each project requires large volumes of materials and equipment, all of which carry embedded carbon.
This creates a clear contradiction. On one hand, the grid enables decarbonization of the wider economy. On the other hand, its construction increases carbon emissions in the short term.
To manage this, TenneT has set targets that extend beyond its own operations. By 2030, it aims to reduce supply chain carbon while nearly eliminating operational emissions.
Consequently, attention is shifting toward industrial suppliers. Steel producers, cable manufacturers, and equipment companies now play a decisive role in determining the grid’s carbon footprint.
“Our ambition is to advance economically viable, cost-efficient solutions that make sustainable materials the new standard,” said Florian Dotzler, director of supply chain management at TenneT Germany.
At the same time, design standards are evolving. Equipment is increasingly assessed based on lifecycle carbon, including how long assets operate and how materials can be recovered at the end of life.
However, the transition will take time. Transformers installed today may operate for decades. Therefore, decisions made now will shape the grid’s carbon footprint well into mid-century.
In addition, supply chains remain global. Copper may be mined in South America, refined in Asia, and assembled in Europe. Each stage adds complexity—and carbon.
“We are advancing the decarbonization of the transformer supply chain, offering lower-carbon and more circular material options,” said Namita Asnani, head of sustainability for transformers at Hitachi Energy.
A grid still in transition
Ultimately, Europe’s electricity grid remains a heavy industrial system. Its carbon footprint is not disappearing. However, it is beginning to change.
This shift remains gradual and largely invisible. It is driven by material choices, supplier strategies, and decisions made far upstream from the power socket. The energy transition, therefore, is no longer only about generating clean electricity. It is increasingly about how the grid itself is built—and how its carbon footprint is reduced.