The Internet relies on cloud computing and storage, which are mostly physically located in large data centers. According to Forbes, there are now more than 5 times more apps running from data centers than in 2018. The size of the largest data centers continues to grow along with their electrical power consumption. Reflecting their growing size, more than 500 of the largest data centers are categorized as “hyperscale data centers”. While data centers have become more energy efficient, they are projected to continue increasing their fraction of total electricity consumption worldwide.

On September 14, 2020, Google restated its “commitment to operate on 24/7 carbon-free energy in all our data centers and campuses worldwide” and “to get this done by 2030”. An example of large data center is the Mayes County Google Data Center near Pryor, Oklahoma.  The main building is almost 2200 feet (0.67 km) long and covers an area of about 23 US football fields. The complex continues to undergo expansion. Hyperscale data center sites can be much larger still.

Mayes County Google Data Center

Mayes County Google Data Center
image source:Xpda, CC BY-SA 4.0, https://commons.wikimedia.org/w/index.php?curid=81148939

Large data centers are operated by tech giants like Amazon, Google, Apple, IBM, Facebook, and Microsoft.  Our internal analysis and industry feedback indicate that companies which build hyperscale data centers are not installing rooftop solar PV for their vast roof area, because there is no viable PV technology on the market that meet with their performance and cost of installation requirements.  At present, many operators of large data centers purchase traditional renewable energy from another region, often in another state or province. This net “decarbonizes” their operations, but locally they consume ­­­fossil fuel-generated electrical power. Our team at PI Energy has met with companies that plan and build data centers and we have learned of the growing interest to incorporate onsite clean energy into future planning, but also frustration at the lack of compatible solutions from the current market technologies.

Concept Hyperscale Data Center

Conceptual illustration of a hyperscale data center.

Here are some of the potential benefits we identified for rooftop PV on hyperscale data centers:

  • Large roof area that could readily serve for solar PV, without additional land-use issues.
  • Increased energy reliability and energy savings.
  • Improved sustainability is desirable for corporate messaging to shareholders and customers.
  • Reduced dependence on grid during periods of strong sunlight and high temperature, when grid stability can be impacted by increased energy consumption on the local grid.

Despite the potential benefits, most large data centers do not have onsite PV. In Mumbai, we found the only example of a hyperscale data center with solar PV integration, though limited to its external walls and not the roof, using traditional solar PV panels that were mounted vertically on the external perimeter walls.

Our internal analysis identified the following requirements for rooftop solar PV for hyperscale data centers:

  • Only lightweight solar modules. Large area roofs of hyperscale data centers are typically not designed for the additional weight required to support traditional crystalline-silicon PV.
  • No bolts or screws should go through the rooftop surface during module installation. No roof perforation is permissible, as it can compromise a water-tight roof covering the server racks.
  • No toxic elements in solar cell, including cadmium, indium or lead. Release of toxic materials is a significant business risk and it can compromise community relations for the data center.
  • Good PV efficiency.
  • Installed-cost needs to be competitive.

Our conclusion is that the requirements for rooftop PV for large data centers cannot be met by any of the current market solar PV technologies. CdTe and CIGS can be lightweight, but they contain toxic elements that can pose substantial risks in the case of a fire, so they are not suitable for this PV application, according to our industry feedback. Many industrial/commercial buildings have unreinforced roofs (“non-weight-bearing” roofs), often made of sheet metal, which cannot bear much additional weight. This roof type is common to large data centers. Traditional crystalline silicon PV can be quite expensive to install on a non-weight bearing roof as it would require costly reinforcement to support the additional weight.

Data Centers Chart

How PV technologies of non-toxic composition and with the potential for good efficiency might address the requirements for rooftop PV on hyperscale data centers.

PI Energy‘s technology is uniquely suited for this growing market segment. The commercial customers of this market opportunity are the tech titans (Amazon, Google, Microsoft, etc.) that are well-funded, and their growing demand for more and larger data centers is expected to continue.

Hyperscale data centers are an example of a new solar energy market addressable by PI Energy’s technology in development. We see new construction and retrofit installations on most commercial/industrial roofs around the world as an attractive opportunity for PI Energy’s technology. Globally, a significant fraction of available roofs have many similar constraints that limit their potential to utilize traditional PV solutions. Installing solar PV on an existing structure, where the power generation and demand are in the same location, can be a highly practical and cost-effective solution for future potential customers. We want to advance a future where a significant proportion of global electricity could be generated on these currently ignored vast spaces, including these non-weight-bearing roofs that are now sitting idle covering commercial and industrial areas.