In the current scenario of climate emergency and the transition toward clean energy sources, the role of transformers for green hydrogen production has become fundamental to ensuring the technical and economic viability of large-scale electrolysis. These units are not merely passive components but rather the critical link that allows for the adaptation of energy from renewable sources—such as solar photovoltaic or wind—to the demanding direct current (DC) requirements of industrial electrolyzers. At EREMU, we apply our more than 60 years of experience in magnetic engineering to design solutions that maximize the performance of every plant, reducing energy losses and ensuring unprecedented operational stability in the hydrogen sector.
The Context of Green Hydrogen and the Need for Power
The decarbonization of the global economy demands sustainable alternatives for sectors that are difficult to electrify, such as heavy industry, maritime transport, and aviation. Green hydrogen, produced by splitting the water molecule using renewable electricity, is the most promising answer. However, this process requires extremely precise energy management.
An electrolyzer needs vast amounts of direct current (DC). Since the electrical grid and renewable plants operate on alternating current (AC), the power conversion system becomes the heart of the facility. This is where transformers for green hydrogen production (specifically rectifier transformers) play a leading role. Their function is to step down the voltage and provide the necessary phases so that rectifiers can convert current efficiently and with the lowest possible ripple.
Technical Requirements of Transformers in Electrolysis Plants
The design of transformers for this sector cannot be standardized. Each electrolysis technology (whether alkaline, PEM, or anion exchange membrane) presents distinct load curves and voltage requirements.
1. Harmonic Management and Grid Quality
Power rectifiers generate harmonics that can distort the electrical grid and unnecessarily heat the transformer. At EREMU, we design multi-pulse transformers (12, 18, or even 24 pulses) that help cancel these harmonics naturally, protecting both the equipment and the client’s grid infrastructure.
2. Handling Overloads and Variable Cycles
Unlike conventional distribution transformers, transformers for green hydrogen production must be prepared for intermittency. If a plant is connected directly to a wind farm, the transformer must withstand sudden power fluctuations without degrading its thermal insulation. Our units are mechanically reinforced to resist the electrodynamic stresses derived from these constant cycles.
3. Efficiency and Loss Reduction
In a hydrogen project, the Levelized Cost of Hydrogen (LCOH) depends largely on the system’s efficiency. A 1% loss of efficiency in the transformer can mean thousands of euros in energy waste over a year. Therefore, we use low-loss silicon steel cores and high-purity electrolytic copper conductors, optimizing the design so that performance is maximized even under partial load conditions.
Design Typologies: Dry-Type vs. Oil-Immersed
At EREMU, we manufacture both technologies, adapting them to the hydrogen plant’s installation environment:
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Cast Resin Dry-Type Transformers: These are ideal for installation in electrolysis containers (skids) or near areas where fire risk must be minimized. They require no fluid maintenance and are highly ecological, aligning with the “green” philosophy of hydrogen.
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Oil-Immersed Transformers: For very high powers in gigawatt-scale plants, oil provides superior cooling and allows for more compact outdoor designs. We offer options with biodegradable vegetable oils to minimize environmental impact in case of leaks.
EREMU’s Custom Engineering: A Differentiating Factor
Most manufacturers offer catalog products. At EREMU, we understand that the hydrogen industry is in a phase of constant innovation. Therefore, our added value lies in collaborative engineering.
Customization of Output Voltages
Electrolyzers typically work at relatively low DC voltages but with currents of thousands of amperes. Our transformers are designed with specific low-voltage secondaries, minimizing the physical distance between the transformer and the rectifier to reduce Joule effect losses in the connection bars.
Intelligent Monitoring (IoT)
We integrate temperature, humidity, and gas sensors (in the case of oil transformers) that allow for predictive maintenance. In hydrogen plants, where availability is critical, knowing that a transformer is operating outside its normal parameters before a failure occurs is vital for project profitability.
Sustainability and Circular Economy in EREMU’s DNA
It would make no sense to produce green hydrogen using equipment whose manufacturing or life cycle is highly polluting. At EREMU, we apply the principles of the circular economy in the production of our transformers for green hydrogen production.
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Recyclable Materials: At the end of their useful life (which typically exceeds 30 years), almost 95% of the transformer’s materials (copper, aluminum, steel) can be recycled.
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Repairability: Unlike low-cost, low-quality equipment, our transformers are repairable. We offer rewinding and technological upgrading (retrofitting) services that allow for extending the asset’s life without the need to manufacture a new one from scratch.
The Impact of Transformers on the Cost of Hydrogen (LCOH)
For green hydrogen to be competitive against gray hydrogen (produced from natural gas), it is necessary to reduce operational costs (OPEX). An optimized transformer reduces auxiliary energy consumption and improves the plant’s power factor.
Furthermore, by reducing harmonics, the need to install expensive external harmonic filters is avoided, which reduces the initial investment (CAPEX) of the project. The transformers for green hydrogen production designed by EREMU are, therefore, a financial tool as much as a technical solution.
Future Trends: Integration with Microgrids
The future of green hydrogen involves isolated microgrids. In these systems, the transformer must interact not only with the electrolyzer and the renewable grid but also with Battery Energy Storage Systems (BESS). EREMU is already working on multi-winding transformers that allow for managing energy flow between these three pillars (Grid, Battery, Electrolyzer) in an integrated manner.
This technical complexity requires a manufacturer that understands not just magnetism, but global power systems. Our international presence and participation in pilot projects throughout Europe place us at the forefront of this technology.
Reliability: The Key to Large-Scale Success
The jump from pilot projects to industrial-scale production (Gigafactories) requires components that offer absolute reliability. A failure in a transformer at a 100 MW plant does not just imply the cost of the repair; it implies the total halt of hydrogen production, affecting the entire downstream value chain, from refineries to transport fleets.
At EREMU, our manufacturing process includes rigorous testing in our own laboratories, ensuring that every unit delivered to a hydrogen project meets the highest international standards (IEC, IEEE). We understand that in the energy transition, there is no room for unplanned downtime.
Conclusion: A Trusted Partner for a Clean Future
The green hydrogen revolution is not a distant promise; it is an industrial reality being built today. However, the success of generation plants depends on the reliability of their most critical components. Transformers for green hydrogen production are the guarantors that renewable energy is transformed into clean fuel efficiently, safely, and constantly.
At EREMU, we are proud to be part of this solution. We combine technical craftsmanship in winding with the most advanced simulation engineering to offer equipment that not only complies with international regulations but exceeds our clients’ expectations in terms of durability and performance.
Are you planning a green hydrogen project?
Do not compromise your plant’s efficiency with standard solutions. At EREMU, we design the transformers for green hydrogen production that your engineering team needs to reach the most ambitious performance targets. From small pilot plants to large-scale installations, we have the production capacity and technical knowledge to accompany you.
Contact our power engineering department and request a technical study for your project here
