Ongoing digitalization is massively increasing data centers’ energy demand. Energy consumption is rising—and often costs as well. From both ecological and economic perspectives, switching to a green data center is highly attractive for companies. Energy-efficient servers and storage solutions, intelligent heat recovery, and virtualization technologies help green data centers conserve resources and sustainably reduce operating costs.
In the past year alone, according to a recent Bitkom study, 45% of data center capacity in Germany was used for cloud applications. It quickly becomes clear: the massive growth in cloud computing capacity—alongside artificial intelligence (AI)—is a key driver of growth in the data center market. However, as technological capabilities increase, data centers’ energy demand is also rising rapidly: according to the study, energy demand of just under 20 billion kWh was expected in German data centers for 2024. By 2030, this figure is very likely to rise to around 30 billion kWh. PWC experts note that even today, around 1.5 percent of global energy consumption is attributable to the data center industry.
The good news: with more efficient server hardware and the use of modern cooling technologies, data centers can be operated significantly more energy-efficiently. This benefits the environment and, in some cases, reduces costs substantially.
Experts refer to green data centers. These data centers are characterized by relying largely on renewably generated electricity, investing in intelligent heat recovery , and using virtualization technologies. This enables much more flexible use of physical IT resources. Data centers do not need to provide a dedicated server per customer that remains underutilized most of the time. Instead, IT resources in the cloud data center are shared across multiple customers, optimizing the utilization of each individual hardware component. What is not needed is therefore automatically switched off. Various providers, including TÜV Rheinland and Blue Angel, offer suitable certification options for green data centers.
Good to know: green data centers are fully in line with the Energy Efficiency Act (EnEfG). Under this act, data centers will be required from January 1, 2027, to cover 100% of their electricity consumption on a balance-sheet basis with electricity from renewable energy sources.
Energy efficiency, resource conservation, and reducing CO2 emissions—the goals are clearly defined. But what comes next? Before companies can adopt a suitable method to save energy, they must first analyze the energy consumption of all devices in the data center. Because anyone who wants to set up their IT in a modern and resource-efficient way needs valid and reliable measurement data. Experts refer to this as an energy audit.
The initial focus is on identifying where there is potential for improvement. For an objective view of energy and resource requirements, it makes sense to record and archive the most important consumption data as a first step. Based on the resulting data series, the next step is to determine where there is potential for savings.
In this context, it is important not only to record IT energy consumption, but also the secondary drivers—above all, cooling, which is an indispensable prerequisite for the highly available operation of IT infrastructures. In addition, redundancies typically exist, up to and including full overdimensioning of supply, distribution, and cooling systems. These excess capacities—especially in UPS systems—operate in normal conditions far from their optimal operating point in the rated load range.
As a rule, the biggest lever for greater efficiency lies in optimized cooling of the server rooms. There are several approaches that green data centers take into account: a simple measure is the strict separation of cold and hot air, as this improves airflow management in the data center. This minimizes the fan speed of the recirculation cooling units, saving electricity. Warm air is drawn in, cooled, and supplied to the cold aisle at the appropriate temperature.
Another measure is raising the room temperature or supply air temperature in the data center’s cold aisle. This approach shortens the time required for mechanical cooling and extends the time for free cooling using ambient air. Against this backdrop, it is not surprising that many cloud providers now operate their data centers in northern, cooler regions such as the Scandinavian countries, as they do not require mechanical cooling there. However, even in Germany, the climate during the cold season temporarily allows operation without compressor power in the air-conditioning units.
With flexible and scalable cloud services, companies can respond quickly to changing requirements. Of course, cloud data centers also consume energy, but leading cloud providers generally rely on modern, energy-saving systems and IT components as well as optimized cooling.
In contrast, the in-house data centers of many German companies operate with sometimes severely outdated hardware and therefore have a high PUE value. This indicates how effectively data centers use the energy supplied. However, modernization is difficult—and above all, costly.
According to PWC, migrating to cloud computing can help companies break free from the proverbial cost trap of their data centers—as they no longer need to continuously invest in infrastructure, hardware, and specialized personnel.
Whether modernized in-house or sourced externally: many companies clearly need to take action. For many, analyzing the status quo and the path to a green data center is an important goal that aligns with their sustainability efforts. This is a key aspect, considering that reducing energy consumption and CO2 emissions is among the most important sustainability goals for many companies—and forms the basis for transparent sustainability reporting.
