The Energy Transition Needs High-Voltage Direct Current

An energy path that Thomas Edison envisioned but did not have the power electronics and digital technologies to create is now proving to be a transformative technology for electricity transmission system operators (TSOs) worldwide: Direct Current (DC).

Nikola Tesla outdueled Thomas Edison in the War of the Currents more than 140 years ago, establishing Alternating Current (AC) as the most convenient way to transmit electricity by using transformers to easily elevate and decrease voltage. Telsa’s solution was, however, not optimal. While DC allows a uniform circulation of electrons within a cable, the uneven circulation of AC creates inefficiencies that result in significant power losses. With AC, eddy current generated by the periodic change of magnetic fields creates additional resistance in the center of the conductor. That causes a skin effect in which electron density is greater at the surface of the conductor. This phenomenon increases the resistance within the conductor, which generates power losses via heat dissipation – called Joule effect. Second, AC generates electromagnetic fields in electric winding devices, which create non-efficient power called reactive power. For these reasons, High Voltage Direct Current (HVDC) transmission losses can be up to 50% less than AC transmission, ensuring that more of what is generated reaches the intended destination.

These numbers matter. At a time when the world is increasingly electrifying, every electron counts. Efficiency is a key pillar for reaching Net Zero. That’s why TSOs are overturning a century of convention to embrace HVDC. 

HVDC is essential for point-to-point transmission, such as connecting offshore renewables to the grid and moving bulk power over long land distances. It can also transmit bulk power in an energy efficient way via submarine links that connect islands or countries, as GE Vernova will do with its Eastern Green Link 1 project linking Scotland to the northeast of England. 

Power electronics and advanced digital computing now allow DC current to do much more: HVDC can interconnect desynchronized High-Voltage AC networks (varying phases or frequency) back-to-back. This allows transmission systems to connect from region to region, or country to country. 

This next step in HVDC technology aims to allow multiple HVDC terminals to be connected, enabling more power sharing and energy security across borders. The future HVDC grid will no longer be  messy point-to-point linear links, but rather a multi-point link. In this type of multi-terminal HVDC network, multiple nodes can connect with another one – creating a highly efficient highway of electrons.  

TenneT, the Dutch-German transmission systems operator, has begun laying the foundation for this with its standardized 2 GW HVDC offshore program designed to be multi-terminal ready. In March 2023, GE Vernova’s Grid Solutions business entered into an agreement with TenneT to build five platforms – three in the Dutch North Sea and two in the German North Sea.

It’s a transformative moment similar to the telecommunications revolution we experienced in the 1980s when ultra-broadband communication networks connected the continents, creating the “Information Superhighway,” the foundation of the worldwide internet. We believe that HVDC will become the new “Electron Superhighway,” the worldwide foundational infrastructure for 21st century electrification and the energy transition.

GE Vernova is committed to playing a central role in forging the path to the future, working to meet the technical challenges that arise, and creating opportunities to push the energy transition ahead with forward-looking solutions. We believe that the next decade will be a promising time for investment in lower carbon energy and HVDC will be at the core. 

This article was written by GE Vernova's Philippe Piron, Chief Executive Officer, Electrification Systems.