Mastering grid upgrades: the impact of decarbonizing supply chains

There is a golden opportunity here. According to the International Energy Agency (IEA), reaching national emission goals will require adding or modernizing more than 80 million kilometers of grids by 2040 – as much as the entire existing global grid today. Now, what would happen if the materials of those grids were green and recyclable?

It is a question often overlooked as transmission system operators (TSOs) go about developing their infrastructure to reduce greenhouse gas emissions. But the truth is, our grids will need not only millions of kilometers of lines, but also hundreds of thousands of new high-voltage transformers and other high-voltage components – millions of tons of steel and copper. A single transmission power transformer can weigh a few hundred tons. The amount of copper needed for its windings is typically 15–20 percent of that weight, and nearly half of the material need for the construction of a transformer, says the IEA, is steel, “of which more than 60 percent is grain-oriented steel.”

This is a fact that the cross-border TSO TenneT and Siemens Energy Grid Technologies are very aware of, and both companies want to change this. “We’re still using too much material that could be made more sustainable,” says Christina Iosifidou, Head of Sustainability Grid Technologies at Siemens Energy. “We have a responsibility to take decarbonization to the supply chain.”

As a leading European grid operator, TenneT intends to lead the transition to clean, circular and decarbonized systems. The company has set ambitious goals to reduce its carbon footprint in line with the Paris Agreement. “We’re actively working to reduce our direct and indirect emissions,” says Florian Dotzler, Head of Supply Chai Management Large Projects Onshore at TenneT.

“Our goal is to reduce our Scope 1 and 2 absolute greenhouse gas emissions by 95 percent by 2030, compared to 2019 levels,” adds Dotzler. “However, the biggest potential lies in the reduction of Scope 3 emissions – Sustainable Procurement is central to our strategy.”

Together, TenneT and Siemens Energy aim to drive efforts in decarbonizing the transmission industry and reduce their combined CO2  footprint by 30 percent by 2030. To reach this goal, the companies have already identified roughly ten joint initiatives across their value chain, such as transformers that use 100 percent recycled copper or green steel.

“Building strategic partnerships and alliances is the driver of technological innovation and the key to success,” says Dotzler. “This new form of collaboration requires mutual understanding and the development of a shared vision. By joining forces, we have the power to make a significant impact.”

Iosifidou has been discussing the materials footprint issue all over the world with partners like TenneT. It all starts with increasing the awareness for embedded carbon emissions in the supply chain. “For a long time, the primary focus was on performance efficiency, which still holds a very high priority,” says Iosifidou.

“However, we must now also consider material waste and the environmental impact throughout a product’s life cycle, because we’re seeing enormous investments in grid extension – a doubling of the global grid length – with assets that will operate for more than 30 years, resulting in a significant embodied carbon footprint.”

A transformer, for example, has a lifespan of up to 35 years and an extensive supply chain. The main carbon footprint during its lifetime originates from operating the transformer (primarily because of transformer losses). But also a considerable CO₂ emissions stem of below 5 percent from the use of raw materials such as steel and copper, as well as the manufacturing of the transformers themselves.

Each point in the chain contributes to a transformer’s overall carbon footprint and requires commitment, communication and transparency for decarbonization. Siemens Energy Grid Technologies already track each year the implemented and planned carbon reduction actions taken by their suppliers. Their next goal, says Iosifidou, is to provide a proof of concept for a decarbonized supply chain within a few years.

The work to decarbonize the supply chain is already making headway with CO₂-reduced electrical steel from producers such as thyssenkrupp, increased transformer efficiency (currently with 0.3 percent losses and improving) and green transformer manufacturing at the Siemens Energy plant in Nuremberg, Germany, where emissions amount to less than one percent along the value chain.

But to make the chain’s sustainable issues more tangible, standardization needs full priority. How do parties all agree on what “green” means? How do they define “green” steel or “green” copper? Here, the industry is only getting started, with switchgear life cycle assessments currently being developed by the International Electrotechnical Commission (IEC).

Creating a regulatory framework for these standards is only now becoming mainstream. Siemens Energy and TenneT are ready to set the benchmark. And the European Union’s taxonomy legislation, defining what is sustainable and what is not, is a strong trigger, with its new sustainability reporting obligations. Because this kind of legislation also affects the world outside the EU, other suppliers are expected to follow soon.

One main hurdle in greening the power grids will be how to deal with the extra costs for greener commodities. “I’m convinced, for example, that with a carbon pricing mechanism in place, green steel will become cheaper than gray steel,” says Iosifidou, “but we have to work on agreements along the value chain about who takes the risks. Other commodities are expected to follow suit, but authorities will still need to establish appropriate grid fees.”

Siemens Energy is aiming to have their proof of concept for green markets in the grid within the next five years. Manufacturing transformers at their plant in Nuremberg already produces nearly zero Scope 1 and 2 emissions, and  their new factory in Charlotte, North Carolina, will have similar results.

But the larger challenges lie upstream in the extraction and manufacturing of base materials like steel and copper in power transformers. For example, the production of copper contributes to around 0.2 percent of all total greenhouse gas emissions, reports the International Copper Association, and for the last 20 years only around 15 percent of copper was recycled.

Using more recycled copper is one way to reduce the carbon footprint, but even here the effects are limited. Recycled copper rates are not expected to exceed 23 percent, while the global demand for copper will only continue to grow. “Capturing and processing the cleanest scrap,” says Iosifidou, “could serve as a closed-loop example to minimize emissions, but to truly decarbonize copper we will have to decarbonize the extraction process.”

Siemens Energy has already started selecting the ten key suppliers out of the four main commodities – steel, copper, aluminum and oil – half of which have signed letters of intent to reduce emissions. “Right now, we have to work case by case,” says Iosifidou, “but each time we succeed, we’re able to step up levels in other parts of the company too. Reducing our own carbon footprint is the biggest enabler for introducing more sustainability for our customers – a circular economy and biodiversity will follow.” All in all, Siemens Energy aims to set a benchmark supply chain decarbonization and the use of sustainable grid technology, paving the way for other industries.

About the author: Netherland-based physicist and author Rolf de Vos has been reporting on global developments in energy and the environment for more than 35 years. Among the first to cover climate change and sustainability, de Vos has also been an acting consultant for organizations such as the Dutch Ministry of Economic Affairs and Climate Policy.

Combined picture and video credits: Siemens Energy