There is a secular trend in the data center industry toward building more facilities away from the construction site, using a modular construction approach. A key driver of this prefabricated construction trend is cloud computing, where large, hyperscale data centers need to be built rapidly and cost-effectively, by operators like Amazon Web Services (AWS), to support the surging demand for their cloud applications. At the same time, container data centers are swiftly being deployed at distributed edge locations to support new software-defined applications and 5G communications, with the goal of reducing latency and lowering bandwidth usage.

Modular data centers are pre-engineered, prefabricated, and standardized buildings, equipped with power and cooling, that house servers and network equipment. The types of modular data centers include container data centers, prefabricated data halls, and prefabricated power & cooling modules.

Dgtl Infra provides an in-depth overview of modular data centers, including their purpose, how they differ from a traditional data center, and their different types. Importantly, cloud service providers (CSPs) and large internet companies, collectively known as hyperscalers, are using modular approaches to build their hyperscale data centers. These hyperscale data center operators are taking advantage of modular designs to achieve: time reductions for construction, cost savings, just-in-time delivery, scalability, a repeatable process, and flexibility.

What is a Modular Data Center?

Modular data centers are pre-engineered, prefabricated, and standardized buildings, equipped with power and cooling infrastructure, designed to house computer servers and network equipment. Typically, a modular data center is synonymous with a container or containerized data center, which combines prefabricated IT, power, and cooling modules into standardized enclosures. Sometimes, a modular data center can be alternatively referred to as a portable, mobile, pod, or skid-mounted data center.

Microsoft Azure Modular Data Center
Microsoft Azure Modular Data Center. Source: Microsoft.

Adding further breadth to the term, modular data center design principles and construction methods are also applied to building traditional data centers at different levels, ranging from components and server rooms to building shells and campuses.

Overall, a modular data center can be deployed outdoors as a standalone building or indoors as part of a larger facility. As such, some modular data centers are simply subsystems of a larger structure, requiring IT, power, and/or cooling modules to be linked together. For example, servers and network equipment may reside in one structure, power infrastructure in another, and cooling systems in a further separate enclosure.

What is the Purpose of a Modular Data Center?

Modular data centers serve two key purposes: they allow for potential savings of time and cost during the construction and deployment of a data center.

  • Time: Modular data center manufacturers, Schneider Electric and Vertiv, have stated that modular facilities can reduce construction and deployment times by 40% to 50%, as compared to traditional data center build methods
  • Cost: Modular data centers offer cost savings through standardized designs and components, which allows for efficient supply chain management. Additionally, they reduce on-site labor by transforming traditional construction methods into an assembly process

What is a Modular vs Traditional Data Center?

A modular data center is an alternative to the traditional data center. In a traditional data center construction process, some or all of the data center components are built on-site out of a collection of parts. In contrast, modular data center construction utilizes components that are manufactured off-site and delivered as pre-engineered, prefabricated, and pretested modules.

Traditional data center construction approaches involve building facilities on-site in large phases, often with extra space to accommodate future growth. Because it takes time to fill these data centers with IT equipment and/or tenants, a traditional construction approach results in underutilization of the asset. In contrast, a modular approach scales data center construction and capacity alongside an operator’s computing needs, limiting the over-provisioning of resources.

Modular Data Center Market Size

The global modular data center market size is estimated to comprise total revenue of $35 billion by the end of 2024 and is forecasted to grow by a 19% compound annual growth rate (CAGR) through 2030, reaching nearly $100 billion of total revenue.

What are the Types of Modular Data Centers?

There are three types of data centers that are generally considered to be modular: container data centers, prefabricated data halls, and prefabricated power & cooling modules. According to Schneider Electric, ~20% of total data center capacity is being deployed through these different types of prefabricated modular data centers.

Server Farm in the form of a Shipping Container with Digital Computer Network Inside for Communications

1. Container Data Centers

Container data centers, also known as containerized data centers, are “all-in-one” prefabricated data halls constructed in standardized units. These units combine the facility structure, IT equipment, power infrastructure, and cooling systems into one cohesive enclosure. For example, the prefabricated components within these containerized data center enclosures include:

  • IT Equipment: Power Distribution Units (PDUs), hot and cold aisle separation, cable trays, lighting, busways, as well as fire detection and suppression systems. The IT space in containerized data centers is designed to support industry-standard server racks, along with storage and networking equipment
  • Power: Uninterruptible Power Supply (UPS) with batteries, switchgear/switchboard, transformer, panelboard, and Automatic Transfer Switch (ATS). Containerized data centers do not include electrical backup generators, which must be integrated separately
  • Cooling: Air- or water-cooled chillers, pumps, drives, valves, and a storage tank. Containerized data centers can potentially incorporate air-side economizers, which utilize outdoor air for free cooling
Container Modular Data Centers
Source: Schneider Electric.

Overall, a single container data center can support a variety of designs, typically ranging from 20 kilowatts (kW) to 250 kW of IT capacity and 4 to 20 racks. On average, this implies power densities of 5 kW to 15 kW per rack.

Physical Features

Each containerized data center ‘unit’ is an enclosure, typically having the same dimensions as a 20- or 40-foot ISO shipping container, as follows:

  • 20’ Container: 20 feet long by 8 feet wide by 8.5 feet tall
  • 40’ Container: 40 feet long by 8 feet wide by 8.5 feet tall

This standardized design is deliberate to ensure that container data centers can be transported efficiently utilizing existing logistics supply chains. Additionally, shipping container designs are easy to procure and have already been tested for structural integrity.

On the other hand, custom-built container data centers, with non-ISO dimensions, are also being manufactured to meet the specific space and technology needs of customers. For instance, a company might require a data center with specific dimensions to fit into a designated area on their premises, where a standard ISO container would not fit.

Deployment

Container data centers are prefabricated in a manufacturing facility and then transported to the end user’s site. These enclosures are then lifted off of the truck using a crane and placed onto a concrete pad. Installation requires only a connection to a power input, chilled water pipes, and networking equipment.

Container data centers are designed to be walk-in, fully integrated, and weather-resistant, enabling them to be deployed in outdoor environments. Typically, containerized data centers are used for new deployments, including both large free-standing data centers and smaller edge facilities.

2. Prefabricated Data Halls

Large wholesale and hyperscale data centers often comprise multiple data halls, which are secure, fully walled rooms housed within a data center that contain servers and network equipment. Data halls are often leased to a single customer, who may have different reliability or power density requirements than other tenants within the broader data center building. For wholesale and hyperscale data centers utilizing a phased construction approach, prefabricated data halls can be incorporated into the building over time, responding to either internal needs or customer demand.

Prefabricated Data Halls Centers
Source: Schneider Electric.

Prefabricated data halls are a type of modular data center deployment that can quickly add ‘white space’ to an existing data center facility, using manufactured components. These prefabricated data halls represent a hybrid or semi-prefabricated approach, because they leverage a combination of traditional and modular data center construction methods.

Prefabricated data halls, which comprise several thousand square feet of space and 50 to 200+ racks, allow large wholesale and hyperscale data centers to be built from smaller subsystems.

Prefabricated data halls involve a ‘hybrid’ of on-site and off-site work in parallel:

  • On-Site: Powered shell and core of the building are constructed at the site, such that they can accommodate space for future data center expansion
  • Off-Site: Factories are used to manufacture prefabricated data halls, which are then transported to a particular data center for installation

Subsequently, the on-site powered shell and core are fitted-out with the off-site prefabricated data halls, which contain the IT infrastructure. These prefabricated data halls are installed on an individual basis in portions of the building space. In turn, the process of building a data center becomes more of a process of assembly as opposed to construction.

Real-World Prefabricated Data Halls

According to NTT Global Data Centers, incremental prefabricated data hall capacity can be brought online in 4 months, equivalent to ~17 weeks. While CyrusOne, another major data center company, states that its “modular data center hall construction typically can be completed in 12 to 16 weeks”.

3. Prefabricated Power and Cooling Modules

Prefabricated power and cooling modules consist of a complete power or cooling system that has been pre-engineered, integrated, and pretested off-site. These power and cooling modules are shipped to a data center and arrive ready for installation.

Power Modules

Power modules comprise the Uninterruptible Power Supply (UPS) with batteries, switchgear/switchboard, transformer, panelboard, and Automatic Transfer Switch (ATS). Electrical backup generators are not included and must be integrated separately.

Power modules can be delivered as a complete power room or as an open, skid-mounted system:

  • Power Room: Fully enclosed system which can be externally mounted and completely exposed to the outdoor elements. Power rooms can either be ‘walk-in’, where personnel can go inside or, alternatively, accessed only via panels on the outside of the enclosure
Prefabricated Power Room Modules
Source: Schneider Electric.
  • Skid-Mounted: Placed into a frame or onto rails and fitted-out within an existing building. Particularly suited for large, indoor deployments, as components are unprotected from the outdoor elements
Prefabricated Power Skid Mounted
Source: Schneider Electric.

Prefabricated power modules serve larger IT loads with a power system layout that ensures redundancy through a distributed architecture. These modules come in different formats. Enclosed power modules provide capacities ranging from 250 kilowatts (kW) to 500 kW. In contrast, skid-mounted designs are capable of supporting even larger capacities, ranging from 1 megawatt (MW) to 2 MW.

Cooling Modules

Cooling modules, also known as hydronic modules, are chilled water systems which comprise air- or water-cooled chillers, pumps, drives, valves, and storage tanks. These cooling modules can be delivered with or without air-side economizers, which utilize outdoor air for free cooling.

Prefabricated Cooling Modules
Source: Schneider Electric.

Modular data centers benefit from cooling efficiency because it is easier to cool a confined enclosure than one large room, in the case of a traditional data center.

Below is an example of modular cooling units at Google’s data center in Mayes County, Oklahoma:

Google Modular Cooling Units Mayes County Oklahoma Data Center
Source: Google.

READ MORE: Google Cloud’s Data Center Locations

What are the Advantages and Disadvantages of Modular Data Centers?

Advantages of Modular Data Centers

The advantages of modular data centers are time reduction for construction, cost savings, just-in-time delivery, scalability, a repeatable process, and flexibility.

1) Time Reduction for Construction

Modular data centers can reduce construction and deployment times by 40% to 50%, as compared to traditional data center build methods. This is primarily accomplished by shifting conventional on-site construction tasks to off-site manufacturing facilities.

The following is a comparison by Digital Realty, a data center company, of the construction timelines for modular versus traditional data centers:

Digital Realty utilizes a modular design architecture to deliver a fully commissioned standard design data center in under 30 weeks, equivalent to ~7 months. In comparison, a traditional data center design and construction process can take 18 to 24 months or longer.

Modular data center components are pre-engineered, preassembled, and pretested at an off-site manufacturing facility. In turn, this eliminates traditional on-site construction tasks such as sourcing raw materials and components, coordinating delivery, integration and testing, and hiring skilled labor. Not having to preplan and manage around these interdependent schedules allows for time savings. Instead, a pre-engineered, prefabricated, and pretested system arrives on-site ready for connection and utilization.

Additionally, modular data centers allow for on-site and off-site work in parallel, which reduces time as compared to a linear, entirely on-site construction process. Particularly, this is relevant for prefabricated data halls, prefabricated power modules, and prefabricated cooling modules.

2) Cost Savings

Modular data centers deliver cost savings by using standardization and reducing on-site labor:

  • Standardization: Economies of scale can be realized through the use of standardized designs and components, which allow for more predictable and manageable costs. Specifically, through supply chain management, raw materials and components can be procured in bulk, rather than on a project-by-project and time-sensitive basis, as is often the case with traditional data centers
  • Labor: Manufacturing data center modules in a factory utilizes less personnel than traditional construction approaches – which can often require over 1,000 construction workers temporarily on-site at the peak of construction for a hyperscale data center. Additionally, modular data centers require fewer specialized architects, engineers, and technicians on-site given that modules have already been pretested in a factory environment for quality control

Overall, a data center’s power (electrical) systems and cooling systems are two of the most expensive categories when constructing a traditional data center, representing 40% to 45% and 15% to 20% of total build costs, respectively. Standardization, in particular, helps to reduce these power and cooling system costs.

3) Just-in-Time Delivery

Modular data center construction – particularly for prefabricated data halls, prefabricated power modules, and prefabricated cooling modules – involves an on-site powered shell and core being fitted-out incrementally with IT, power, and cooling infrastructure, based on demand from customers. This approach allows for the gradual build-up of infrastructure to match the specific requirements of a customer, which could be a commitment in the form of a pre-lease for data center capacity.

By delivering capacity incrementally, on a just-in-time basis, capital expenditures can be significantly reduced and investment can be deferred until as late as possible, improving return on investment (ROI). At the same time, data center providers can minimize risk by ensuring that they only begin construction on a data center once they have a pre-lease in-place for a specific amount of capacity.

4) Scalability

Modular data centers can be scaled by adding more standardized units or modules as demand for capacity grows. Indeed, the only limitation on scalability for a modular computer facility is the supporting on-site infrastructure (e.g., electrical substations) and available land.

As an example, power modules allow for a straightforward way of scaling power in relation to actual capacity needs, by simply deploying additional modules outside of the white space of a data center. To this end, hyperscale data center operators, such as Meta Platforms (Facebook), are using prefabricated power and cooling modules to incrementally build-out their data center campuses – which can often span 10+ buildings, 100+ megawatts, and 1+ million square feet.

5) Repeatable Process

Modular data centers bring simplified and standardized designs, allowing hyperscalers to add capacity on-demand in pre-defined building blocks. This approach is repeatable because pre-defined building blocks eliminate the need for hyperscalers to design a new data center each time and at every single location where they build.

As such, companies like Amazon Web Services (AWS), which have global data center operations, can deploy standardized facilities regardless of the location of their project.

6) Flexibility

Modular data centers, particularly container data centers, offer flexibility because they can be delivered to a site to fill an immediate and/or temporary need, as well as be deployed in a location where it is not easy to construct a traditional data center. For example, IoT technology necessitates the deployment of data centers in environments closer to end users, such as dense urban cities at the network’s edge.

Flexibility in modular data centers is also evident because older modules can easily be replaced when they become obsolete or if newer technology is needed. This approach ensures that modular data centers remain up-to-date and efficient by allowing for easy replacement of outdated components with newer, more advanced technology.

Additionally, modular data center systems allow operators to add incremental IT, power, and cooling infrastructure, thereby accommodating increasing power densities within their facilities. As end user power density needs increase, for applications like artificial intelligence (AI), modular facilities offer the flexibility to meet these IT demands.

Disadvantages of Modular Data Centers

The disadvantages of modular data centers are transportation risk, supplier risk, durability, and physical security.

1) Transportation Risk

Modular data centers typically are prefabricated in an off-site factory, often located hundreds of miles from where the on-site powered shell and core of the building is being constructed. Consequently, these data center modules need to be transported to a specific site for installation.

The transporters and riggers must be extremely careful with each data center module as one accident during transportation could cause the entire module to need significant repairs or replacement. As a result of a mishap, the entire sequence of installation could be delayed.

2) Supplier Risk

Modular data center manufacturers, such as Schneider Electric and Vertiv, are limited in options, as compared to general contractors with traditional data center construction experience. This concentrated base of suppliers creates execution risk if a particular modular data center manufacturer does not perform.

3) Durability

Modular data centers, especially container data centers that are situated outdoors, may be less resilient to natural elements compared to traditional data centers. For example, these facilities are susceptible to damage from a variety of sources, including rain, wind, vandalism, animals, and insects. As such, the building enclosure and internal equipment are more exposed to corrosive elements such as rust, compared to traditional data centers.

4) Physical Security

Modular data centers typically are not built with the robust physical security layers that traditional data centers offer. Therefore, it is the responsibility of the end user of a modular facility to provision their own physical security measures, such as anti-climb fencing, a main entrance gate, security guards, biometric identification, and more.

Modular Data Center Manufacturers

The major modular data center manufacturers are Schneider Electric (including APC), Vertiv, Huawei, and Eaton. While other third-party modular data center solutions providers include Cisco, Dell, Hewlett Packard Enterprise (HPE), IBM, and Johnson Controls. These companies specialize in the manufacturing of modular infrastructure products and solutions, such as power and cooling modules, used in data centers.

Mary Zhang covers Data Centers for Dgtl Infra, including Equinix (NASDAQ: EQIX), Digital Realty (NYSE: DLR), CyrusOne, CoreSite Realty, QTS Realty, Switch Inc, Iron Mountain (NYSE: IRM), Cyxtera (NASDAQ: CYXT), and many more. Within Data Centers, Mary focuses on the sub-sectors of hyperscale, enterprise / colocation, cloud service providers, and edge computing. Mary has over 5 years of experience in research and writing for Data Centers.

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