DC power distribution at the rack level represents a significant innovation in data center power infrastructure, offering substantial efficiency gains and aligning well with the power requirements of modern AI hardware. This approach, exemplified by ABB's 380V DC data center in Zurich, demonstrates the potential for DC systems to revolutionize power delivery in high-performance computing environments.

The primary advantage of DC distribution lies in its ability to eliminate multiple AC-DC conversions typically found in traditional AC power systems. In a conventional AC data center, power undergoes several conversions: from AC to DC at the uninterruptible power supply (UPS), back to AC for distribution, and then to DC again at the server level. Each conversion introduces inefficiencies, resulting in energy losses. By implementing a DC distribution system, these conversion stages are significantly reduced, potentially lowering energy losses by 10-15% compared to traditional AC systems. This efficiency gain is particularly relevant for AI data centers, where power consumption is a critical factor. Most GPUs and AI accelerators operate on 12V DC, making a DC distribution system naturally compatible with their power requirements. The reduced number of conversion stages not only improves efficiency but also enhances reliability by eliminating potential points of failure. The impact of DC distribution on overall data center efficiency is substantial. Data centers implementing this technology have achieved power usage effectiveness (PUE) ratings as low as 1.1, a significant improvement over the 1.5-2.0 PUE typical in AC facilities. This improvement translates directly to reduced operational costs and lower environmental impact. Another key advantage of DC distribution is its ability to support high power densities. Modern DC systems can deliver up to 50 kW per rack, meeting the intensive power requirements of AI workloads. This high-density capability is crucial as AI hardware continues to evolve and demand more power in compact form factors.

However, the adoption of DC power distribution faces several challenges. One significant hurdle is the lack of standardization in the industry. Competing voltage standards, including 380V, 400V, and 48V DC, complicate equipment compatibility and interoperability. This fragmentation can lead to concerns about vendor lock-in and future scalability. Safety is another critical consideration in DC power systems, particularly at high voltages. The risk of arc flash in high-voltage DC systems necessitates specialized safety protocols and training for data center personnel. While these risks can be mitigated with proper design and procedures, they represent an additional complexity in system implementation and operation. The initial cost of DC power systems can also be a barrier to adoption. DC systems typically come with a 15-20% price premium compared to their AC counterparts. This higher upfront cost includes specialized DC power distribution units, DC-compatible IT equipment, and potentially more expensive cabling and connectors rated for DC use. However, it's important to note that these higher initial costs are often offset by long-term efficiency gains and potentially reduced maintenance needs.

Worth watching:

• ABB (Switzerland): A pioneer in DC power distribution for data centers, ABB has demonstrated the technology's potential with their 380V DC data center in Zurich. They offer a range of DC power systems and components designed for high-efficiency data center applications.
• Vertiv (USA): Formerly part of Emerson Network Power, Vertiv provides DC power systems and distribution solutions for data centers. Their offerings include high-efficiency rectifiers and DC power distribution units designed for modern data center needs.
• Eaton (Ireland/USA): A major player in power management solutions, Eaton has been actively developing DC power technologies for data centers. They offer DC power systems and are involved in industry initiatives to promote DC adoption.