neFO | DC- Coupling

New Era at Norvento

Integration of a direct current factory: The Norvento TECHnPower case project, the new zero-emission neFO (Norvento Enerxía Factory Zero) plant

In the current context of energy transition, the electrification of industry faces a fundamental challenge: optimising energy efficiency, maximising the integration of renewables and reducing losses associated with energy transport and conversion. One of the emerging technological paradigms for addressing this challenge is the adoption of internal direct current (DC) grids in industrial environments.

Direct current (DC) is a unidirectional flow of electrons that maintains constant polarity and magnitude over time, as opposed to alternating current (AC), where polarity and amplitude vary cyclically following a sinusoidal wave. In the industrial field, this difference is not merely academic, but has profound implications for network architecture, equipment sizing and the overall efficiency of installations.

Norvento TECHnPower’s new self-sufficient, carbon-neutral Norvento Enerxía Factory Zero (neFO), designed to be a benchmark for innovation in the sector, will be built using this direct current model, making it a pioneering facility in Spain in implementing a fully DC electrical distribution system. While at the Norvento Enerxía Innovation Centre (CIne), the company’s headquarters, the facilities have been connected to AC, neFO will opt for DC connection, which will allow the company to gain experience in both architectures and compare their advantages.

The primary reason for implementing a direct current (DC) coupling in the new neFO plant is that most of the energy assets operate natively in DC. More specifically, the plant will have 2 MW of rooftop photovoltaics, 2 MW of battery storage (BESS), an electrolyser, a fuel cell and an electric vehicle charging infrastructure. With a common DC bus, this equipment will be connected directly without intermediate AC/DC conversions, reducing losses and complexity. In addition, one of Norvento TECHnPower’s Multi-MW nXL converters will generate the factory’s AC voltage and act as an interface with the grid if necessary, as most of the time this production centre will operate as an island, completely disconnected from the electricity and gas grids.

DC grids eliminate the need for multiple conversions between AC and DC, which in most industrial plants are performed to power electronic equipment, variable speed motors, control systems, LED lighting and other consumers that intrinsically operate on direct current. These conversions, performed using rectifiers or power supplies, involve losses ranging from 2% to 8% per stage. In a conventional factory, the sum of these inefficiencies can translate into significant additional energy consumption and, therefore, an increase in associated emissions.

The neFO scheme, on the other hand, enables direct energy flows: it makes it possible to generate hydrogen from photovoltaics and BESS when necessary, it facilitates charging the BESS directly from photovoltaic panels without redundant rectification/inversion and it allows energy from the fuel cell to be injected into the DC bus, as well as meeting the plant’s AC consumption through the nXL.

In an AC system, phase synchronisation, frequency regulation and reactive power compensation are critical elements for grid stability. These aspects involve the use of transformers, capacitors and additional compensation systems. In contrast, in a purely DC system, frequency oscillations and the need for synchronisation between generators and loads are eliminated, simplifying the topology and allowing for more direct integration of renewable sources such as solar photovoltaics, which natively produce energy in direct current. Other technical advantages of a DC grid include its ability to operate at higher voltages with less risk of electromagnetic interference, and its ease of implementing hybrid microgrids that integrate renewable generation, storage and consumption in a highly controlled manner using advanced energy management systems (EMS).

There are precedents of factories and data centres that have adopted DC distribution schemes, such as Mercedes-Benz’s Factory 56 in Germany, although on a much smaller scale than Norvento Enerxía Factory Zero (neFO). This production centre is already exploring similar DC microgrid and advanced electrification solutions, reinforcing the viability of large-scale DC grid implementation in industrial environments. Other examples include the DC Factory project in Barcelona and the facilities of companies such as ABB in Switzerland and General Electric in the United States. These cases have demonstrated reductions in energy consumption of between 5% and 15%, improvements in the reliability of the internal network and greater ease of incorporating battery storage, which operates natively in DC. In the case of the new neFO plant, this approach will allow the entire production chain to be optimised to work without unnecessary conversions, reducing operating costs and increasing process efficiency.

Norvento TECHnPower’s zero-emission, self-sufficient neFO factory not only represents a milestone in the implementation of direct current technology at an industrial level in Spain, but also marks a clear direction towards the optimisation of energy processes in the industry of the future. The transition to DC networks is not a passing trend, but a structural change that, as implementation costs are reduced and safety and connection protocols are standardised, will become the norm for facilities seeking to maximise their competitiveness and sustainability.

References

[1] IEEE Std 946-2020. IEEE Recommended Practice for the Design of DC Auxiliary Power Systems for Generating Stations.
[2] ABB Technical Paper: ‘DC Distribution for Industrial Facilities’. ABB, 2023.
[3] International Electrotechnical Commission (IEC). IEC 60038: Standard Voltages.
[4] GE Energy Report: ‘High Efficiency DC Power for Industry’, 2022. [5] Mercedes-Benz Group. (2020, 2 de septiembre). Con la Factory 56, Mercedes-Benz presenta el futuro de la producción. Recuperado de: https://group.mercedes-benz.com/innovation/digitalisation/industry-4-0/opening-factory-56.html

Photo showing where aluminium is extracted: Svetlana bauxite.