Brochure · EN — Siemens Energy brochure (2022, 6 pages, marked Unrestricted) on how power transformers contribute to the energy transition. It covers the climate-neutral-by-2030 program and green factory network (insulation-oil reuse in Jundiaí, 1 MW rooftop PV in Zagreb, e-mobility at Nuremberg and Weiz), product technologies that make transformers sustainable (efficiency-optimized designs, heat recovery, biodegradable ester insulation liquids including the world's first 400 MVA / 420 kV natural-ester transformer, Pretact EcoSafeT), digitalized Sensformer Advanced/Edge transformers with digital-twin capability, and circular-economy initiatives such as Life Cycle Assessments, raw-material passports, and more than 95% end-of-life recyclability.
Climate change and accelerating electrification are reshaping energy systems worldwide: studies project global energy demand could rise by up to 25% by 2040, with greenhouse-gas emissions climbing alongside it. For a transformer manufacturer this creates three central challenges — supporting grid expansion for reliable transmission of that rising demand, reducing customers' carbon footprints through environmentally friendly products, and coping with growing grid fluctuations caused by increasing renewable infeed.
Today more than one sixth of the world's electricity is generated with Siemens Energy products, and decarbonizing the entire value chain — supply chain, operations, and portfolio — is central to the company's sustainability program. The headline goal is climate neutrality by 2030, supported by a switch to 100% green energy consumption by 2023. Notably, more than 40% of power transformers produced today are generator step-up units (GSUs) for renewable energy sources, while GSUs for conventional sources represent less than 5% of production volume.
Power transformers sit at a key point in the energy value chain. According to the IEA, transmission expansion needs in the coming decade are 80% higher than in the last one. Phase-shifting transformers and variable shunt reactors protect power lines from overloads, provide active power-flow control, and compensate reactive power losses, while step-up transformers with efficiency ratings exceeding global regulations enable the transition to solar and wind generation.
Reusing insulation oil: insulation oil ages and degrades in service, and the polar components that form historically prevented its reuse. A team at the Jundiaí, Brazil factory invented a purification process that removes these polar components and restores the oil to its original state. Purifying and reusing more than 300,000 liters of oil each year cuts CO2 emissions by 770 tons in Brazil alone, and several other power transformer factories have adopted the process.
E-mobility at the factories: the Nuremberg (Germany) and Weiz (Austria) plants installed electrical charging stations on-site, electrifying the company fleet and encouraging employee EV adoption. All power transformer factories are also switching to 100% electric construction machines and vehicles such as cranes and forklifts.
Rooftop solar in Zagreb: 3,230 photovoltaic panels were installed on four buildings of the Zagreb, Croatia factory, generating regularly since June 2018. The 1 MW installation covers more than 17% of the factory's electricity consumption and avoids 415 tons of CO2 per year. Beyond decarbonization, the sites reduce water consumption, create green areas to preserve biodiversity, automate lighting and heating to cut power use, and reuse or eliminate packaging materials to reduce waste.
Highly efficient products ensure low losses: over a transformer's lifetime, transformation losses are in many cases the biggest contributor to its CO2 emissions. All units are built to local energy-efficiency regulations, and designs are optimized for the balance between transformer losses and weight-induced CO2 emissions. A peak efficiency index calculator helps customers compare efficiency ratings and identify the most ecological and economical option.
Heat recovery can further maximize overall efficiency by putting transformation losses to use, up to the highest power ratings. The usable temperature range for heat recovery can be extended with heat pumps or alternative insulating liquids such as esters.
Alternative insulation liquids: traditional mineral oils are non-biodegradable. Biodegradable mineral oil made from biowaste behaves similarly to conventional mineral oil with a smaller carbon footprint. Biodegradable natural ester goes further — it captures CO2 from the atmosphere and has a higher flash point, enabling operation at higher temperatures or extending transformer lifetime. Synthetic ester allows cold starting at very low temperatures and offers several end-of-life options including regeneration and full recycling. Biodegradable liquids also prevent harm to groundwater and the surrounding area.
Siemens Energy has more than 15 years of experience in ester technologies. The world's biggest natural-ester-filled transformer — rated 400 MVA, 420 kV — was built at the Nuremberg factory for Kupferzell, TransnetBW. These environmental properties are bundled in the Pretact EcoSafeT program and can be combined with safety functions such as a rupture-safe tank design; the Pretact EcoSafeT fire-safe substation concept sets new standards for substations in environment, health, and safety.
Sensformer Advanced and Sensformer Edge add a digital layer of operational transparency to power transformers, helping operators manage growing grid complexity. Both feature digital-twin technology — a virtual replica of the specific transformer based on its design and operational parameters — that delivers real-time performance and condition information and simulates load scenarios in advance.
The digital twin serves three scenarios: simulating any load and ambient-temperature cycle 24 hours into the future, determining permissible overload under defined boundary conditions, and automatically calculating the transformer's relative aging. These capabilities help extend transformer lifetimes and increase grid loading, letting operators meet rising power demand with their existing fleets.
Beyond factory measures and product features, Siemens Energy is expanding environmental transparency by issuing certified Life Cycle Assessments and Environmental Product Declarations for each transformer according to the respective norms, and will provide a transformer-specific raw-material passport documenting CO2 emissions along the value chain.
A strong circular economy is central: materials comply with international standards, suppliers are encouraged to use increasing shares of recycled, lower-CO2 materials, and recycling partnerships maximize the recycled share at end of life. More than 95% of a power transformer can be recycled after a lifetime that often exceeds 30 years.
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