“If you look at old data centers, per rack, which is a seven-foot telecom rack, it used to be 30 kilowatts. Today they went to 150. Today we are already at 250 kilowatts. And now we are talking about getting them up to a megawatt. If you stay at 50 volts and it's a megawatt, you're looking at 20,000 amps. … That's just not feasible. So the push is to go to 800 volts DC, so we can drop the amount of current delivered to each server by almost 20x.”
Volts · Climate & Energy · November 2026
Context
David Roberts asked why AI data centers are the first big market for solid-state transformers. Belur explains how fast rack power is rising and why delivering a megawatt at today's low rack voltage would need impractical current, which is the case for 800 volts DC.
Transcript
EVs and smart car and autonomous driving and cars and you could have an impact there. But I think it's constant race that you're in. You're going to constantly make sure that you're ahead of somebody who intends to do harm.
…mentioned this earlier, is just that a data center load, because of the way AI works and AI training works, is just going to be jumping up and down constantly. It's a very dynamic load. So talk about just what need our data centers creating and then how do solid state transformers meet that need?
Yeah. So like in every business, you look at business opportunities and look at demand. And data center was one place where very significant demand has been created and it's Because of exactly the things that you pointed out, a couple of things are happening. One is the loads becoming extremely dynamic, particularly training loads, because of the way the transformers are computed, mathematically operated on, coefficients are generated, et cetera. So these loads may go from 10% to 100%, you know, five times a second, right? Yeah. So they're fluctuating a lot. But the second thing that's a big driver also is just the amount of power that these computes are beginning to demand, right? If you look at old data centers, they were per rack, which is a seven-foot telecom rack, used to be 30 kilowatts. Today they went to 150. Today we are already at 250 kilowatts. And now we are talking about getting them up to a megawatt. Now, recall the very first narrative that you had, which said, hey, what do transformers do? They boost up the voltage. So if you stay at 50 volts and it's a megawatt, you're looking at 20,000 amps. 50 volts is what traditional racks run at 48 or 50 volts or 54. There's some nuance there, but let's assume 50. You're…
So, this is all by way of saying that data centers are shifting toward using DC inside the building, basically.
That's exactly right. There's a push to move towards 800 volts DC inside what's called the white space or the space where all the computer infrastructure lives. And where did 800 come from? That's an interesting story as well. 800 came from the automobile industry because when you do DC charging of…
Right. So you want something in between those loads and the utility that smooths it out and that presents basically a smooth, steady demand to the utility, to the bulk grid. To
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