Must-Read Research: Sustainability Gains Momentum While PUEs Plateau

Jan Michael Cruz •

Over the last couple of years, sustainability has become an all too important topic for businesses. What used to be a buzzword for some, is now a strategic priority for many. This is not surprising considering how imperative it is to tackle the challenges of net-zero emissions, energy efficiency, preservation of ecosystems, and improving the quality of life, just to name a few.

The data center industry is at the forefront of sustainability initiatives and strategies. The exponential growth of data center sites has brought with it closer examination from policy makers and environmental groups, not just on carbon emissions, but on the use of resources, including water.

Sustainability factors are increasingly part of many data center operators' CAPEX and OPEX considerations. Even investment firms are now integrating sustainability measures into their investment process.

This drive to sustainability strategy is evident from research conducted by the intelligence unit of Uptime Institute, which recently published its 11th annual global data center survey. This much-anticipated report is one of the most comprehensive and longest-running studies of its kind in our industry. It covers various topics such as data center operation, data center equipment, efficiency, trends, and sustainability.

The survey revealed that “data center sustainability is growing in importance”, but also reinforced that more work needs to be done, especially on how organizations track their environmental footprint. Let’s go into some of the results:

  • In 2021, the average annualized Power Usage Effectiveness (PUE) is at 1.57 compared to 1.59 in 2020. It shows that operators are maintaining good and stable efficiency levels, but it also means that the levels have plateaued. This indicates that previous efficiency strategies of improving airflow management and replacing aging equipment have been achieved.
  • Then again, the survey also mentions that the next efficiency gains can come from highly efficient cooling such as liquid cooling or solid-state cooling
  • Efficiency gains can also be found at the IT-rack level – Data suggests a link between power density and the size and efficiency of a data center. It shows a shift toward more power racks – between 5 and 10 kW – in facilities larger than 3 MW of maximum IT load
  • However, the survey also revealed that it’s time to track other metrics to widen the scope of sustainability measurement. This includes measuring and tracking server utilization, water usage, IT or data center carbon emissions, and e-waste or equipment life cycle.


As Uptime points out: “Overall, the picture is clear: After large efficiency gains through the first half of the 2010s, average PUEs have remained relatively stable for the past five or so years. There is a clear explanation for this. Even as a growing number of new builds sport design PUEs of 1.3 or better, it is not economically or technically feasible for many operators to perform the major overhauls needed for better efficiency in many older facilities. Further improvements will require significant change. In existing facilities this may include retrofitting with highly efficient cooling; in new data center designs it may require adopting innovative approaches or technologies, such as direct contact liquid or solid-state cooling.”

Another important area for data center sustainability includes server utilization: “…it is still common at smaller and privately owned enterprise data centers that the electric utility bill is paid by property management, which may have little interest or say in how the compute infrastructure is built or operated. This disconnect could explain why most still do not track server utilization, arguably the most important factor in overall digital infrastructure efficiency. Even fewer operators track emissions or the disposal of end-of life equipment, which underscores the data center sector’s overall immaturity in adopting comprehensive sustainability practices.”

Aside from sustainability, the survey reveals an industry that is growing significantly but is trying to cope with many complexities and challenges.

Those challenges include:

  • Impact of outages – According to the survey, about a fifth of outages are classified as serious or severe. While fewer, it is also found out that these outages cause significant loss of time, substantial financial losses, and reputational damage.
  • Supply chain disruption will persist – In recent years, the pandemic, extreme weather, and political factors cause tightness of supply for many key components like chips, power components, and electrical equipment. Most suppliers expect this disruption to continue for the next two years. They also predict that this will affect either CAPEX projects or availability of IT equipment, or even both.
  • Data center staffing shortages continue – Data center operators continue to have staffing challenges. This is due to many factors namely, staff being hired away by competitors and non-competitors and an aging workforce in mature markets leading to many experienced professionals retiring.


Meanwhile, aside from highly efficient cooling and sustainability initiatives, there are also other opportunities that the industry can look forward to, namely:

  • Edge data centers expand – Many expect to build or operate more edge data centers to process data closer to users and devices. Moreover, suppliers of data center equipment expect most of their customers to own edge micro data centers (<150 kW) within 5 years.
  • Lithium-ion battery use – the survey showed that nearly half of operators have adopted Li-ion for some of their centralized UPS systems. With its costs dropping and ever improving performance, batteries using Li-ion chemistries are the favorites in displacing lead-acid technology.


The optics could not be any clearer. Sustainability will impact many decision points moving forward: how we measure efficiency, the most appropriate cooling solution, and how to maintain efficiency as new opportunities, like the edge and Li-Ion batteries, take shape.

If you are interested in other research reports around the data center and critical infrastructure, please check out Vertiv’s new Analyst Research and Market Insights page.

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