/ FAE INTERVIEW
How high-voltage DC is changing our power infrastructures
The trend toward high-voltage DC (HVDC) power is quickening in response to growing demand from AI and EVs. Below, Avnet Senior Technology Writer Philip Ling talks with Mark Tomas, an Avnet principal power field account executive, to find out more.
HVDC transmission uses voltages from 100 kV up to 800 kV. It reduces transmission losses and makes it simpler to share resources across different power networks. But the real drive behind its adoption is our demand for more power.
The power used by data centers dedicated to artificial intelligence (AI) is expected to reach around 90 TWh by 2026, according to research from Statista. That figure was zero in 2022. Many of the AI data centers will be located close to the demand to reduce latency. That means building more data centers in urban areas and providing them with more power.
At the same time, legislation in some countries is requiring office buildings to make provision for charging electric vehicles (EVs) in their parking areas. In some cases, over 50% of the parking bays must be equipped with EV charging. It is probable that all those bays will be charging EVs during the working day.
Both these trends see demand for significantly more power at the edge of the distribution network and further from the source. Generating more power isn’t the problem. Gas, coal and nuclear-powered turbines can typically work harder. As power consumption goes up, the problems inherent with transmitting AC power over the existing infrastructure become more apparent.
HVDC aims to address the issue. Transmitting HVDC is more efficient than high-voltage alternating current (HVAC), as Mark Tomas, an Avnet principal power field account executive in North America, explained.
Reactive power loss
According to Tomas, it’s the inductive nature of our power lines, plus the losses involved with up- and down-converting the AC voltages at either end of the distribution network that is becoming a problem.
DC saves energy
This raises the question of where and how we could use HVDC to meet the emerging demand coming from AI data centers and EV charging.
Stepping down HVDC
The components needed to handle HVDC are already available. The semiconductors used in AC distribution, such as IGBTs, thyristors and silicon-controlled rectifiers (SCRs) will still be used, and the development of wide bandgap devices such as silicon carbide (SiC) FETs will also be important in HVDC.
Semiconductors for HVDC
There are, of course, costs involved. If we migrate from AC to DC we can potentially continue to use much of the same wiring, but it is more likely that DC distribution will not fully displace AC, so new wiring may be needed. The conversion between AC and DC will also require new equipment.
The cost of HVDC
Will HVDC change the way we use power? It will at some level. Mark Tomas sees the real benefits in using it selectively to target the power-hungry applications that are emerging in urban areas.
What's next for HVDC?
It seems clear from analyst data that HVDC deployment is set to continue, with capacity going from MWs to GWs in the coming years. The underlying trends driving that transition are EVs and AI. Both of those trends are here for the long term.