Scaling on Demand: Decentralizing Data Center Power for a World Gone Remote

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Vito Savino is wireline and data center segment leader for ABB Power Conversion.

The impact of worldwide stay-at-home orders and social distancing measures on digital infrastructure was as immediate as it was immense. Entire industries shifted massive numbers of employees to remote work, unleashing demand for digital tools and network services that would allow operations to continue with minimal disruption.

According to an IEA report, between February and mid-April 2020, global internet traffic surged by 40 percent. Microsoft Teams saw a 70 percent increase in usage in March alone. Today, more than eight months later, one thing is clear: returning to normal has been replaced by a new normal, one in which the cloud is considered mission-critical and digital tools like video conferencing and virtual services like telehealth essential.

Not surprisingly, the impact of this digital transformation amplifies a broader set of challenges for data center operations. First, how can data centers maintain resiliency, efficiency, and reliability amid the unprecedented and ever-growing demand for cloud-based, business-critical applications? Second, how can data centers ensure their facilities are well prepared to scale operations in response to rapidly changing and continuously increasing capacity demands?

Responding to these challenges requires that data center operators attend to the critical role power architectures play as potentially enabling or limiting factors for expanding data center capacity.

Maximum Capacity: The Limitations of Centralized Power Architecture

There are a few main factors that typically constrain data center expansion: physical space, power system capacity, and cooling capacity. However, a more in-depth look reveals that whether or not power acts as a constraint depends on the type of distribution architecture a data center deploys.

For most data centers, a centralized power architecture is the beating heart of the facility. In this scenario, a centralized uninterruptible power supply (UPS) system converts power from the AC utility grid to DC. The power is then stepped down during a series of additional points of conversion to provide the power levels required by the computing equipment in the data center racks. In the event of a significant disruption like utility failure, backup power is distributed from large battery banks at this central power location to critical equipment across the data center.

Most data centers use such centralized power architectures, but they are not without limitations. Take scalability, for example. When it comes to scaling to meet increased processing needs and capabilities, there may not be room to add more electrical infrastructure in the power room.

Centralized UPS power and backup capacity support a data center’s anticipated load based on forecasts made at the earliest facility design stages. However, because computing and power equipment are not installed all at once – especially in colocation data centers – capacity limits may quickly prove obsolete once the load is built out.

This also presents challenges as data centers upgrade to higher-capacity and higher-density networking equipment to meet ever-increasing computing needs.

As a result, data centers that rely solely on a centralized UPS architecture run the risk of exhausting their power capacity before filling all of their data center's available white space, and they may inadvertently be limiting their ability to scale rapidly to meet future demands.

Beyond Capacity: The Benefits of a Decentralized Power Architecture

So, how can data centers overcome power capacity constraints and ensure that their infrastructure is well-equipped to respond to growing demand while still maintaining maximum uptime and resiliency? The answer is adopting a decentralized DC power architecture.

As opposed to a centralized UPS, backup power in a decentralized system is distributed throughout the facility and designed to live proximate to the critical load equipment. By grouping small loads and placing critical battery reserves close to the physical computing equipment, decentralized systems reduce the potential single point of failure to a smaller portion of the facility, improving resiliency amid increasing demand without burdening the entire site.

Instead of relying on numerous AC-to-DC conversions, distributed DC power architecture directly connects the AC utility source to the cabinet, where smaller, more power-dense batteries and rectifiers are housed directly inside along with the networking equipment. This approach helps reduce the number of power conversion steps required to step down utility power to the needs of the servers and routers, helping improve efficiency, reliability, and scalability.

Perhaps the most critical feature of a decentralized UPS architecture is it allows data centers to meet increased demand by deploying equipment-specific resources that can scale according to needs. New cabinets can expand capacity as necessary, while additional rectifiers and battery modules can increase power for servers added to open racks. By relying on DC power components that connect directly to the AC utility feed, a decentralized power architecture allows facilities to operationalize stranded white space and maximize infrastructure without placing any additional strain on their existing UPS system.

Simply put, a distributed DC power architecture allows data center operators to add power and load concurrently. Unlike a centralized UPS, which constrains how much and where a data center can grow (from physical footprint and cable runs to battery and PDU capacity), a decentralized power architecture is designed to scale. It is precisely what data center operators need in a world of rapid, unexpected spikes in customer demand.

Preparing for the New Normal

While its unclear how long we will remain physically distanced, it's clear that we've already witnessed nothing less than a paradigm shift in how populations across the globe live, work, collaborate, and communicate. The digital transformation of the past eight months has only served to accelerate a broader set of long-term trends already underway, including advancements in AI, automation, and data analytics, as well as the evolution of 5G, IoT, and smart cities.

Against this backdrop, data centers face familiar long-term challenges imbued with a new sense of urgency. Now more than ever, data center operators need to reimagine the power architectures at the heart of their facilities. In the face of what are sure to be continuously increasing demands on capacity, introducing a decentralized, distributed power architecture is a critical step towards developing data center infrastructure with the flexibility to adapt and keep pace with whatever comes next.

Opinions expressed in the article above do not necessarily reflect the opinions of Data Center Knowledge and Informa.

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