Energy Consumption

  • NfS: Environmental Matters/Energy
  • GRI 302
  • GRI 302-1
  • GRI 302-2
  • GRI 302-3
  • GRI 302-4
  • GRI 305
  • GRI 305-1
  • GRI 305-2
  • GRI 305-3

Our network infrastructure and the server capacity provided by our data centers are needed to supply internet and telecommunications services to our customers. At the same time, their operation accounts for most of our energy consumption. Roughly half of the Group’s expenditure on electricity comes from our global data center operations. Most of the other half results from our fiber-optic network operations; the small remainder is attributable to our office buildings. Further details on the information given in the following table can be found in the relevant sections.

  • NfS: Nonfinancial Key Performance Indicators

Energy consumption




Electricity consumption - data centers in MWh




Electricity consumption - fiber-optic network in MWh




Electricity consumption - office buildings in MWh(1)




Total electricity consumption in MWh




Heating consumption (natural gas and heating oil) in MWh




Gasoline consumption in MWh




Diesel consumption in MWh




Total fuel consumption in MWh(2)




Total energy consumption in MWh




Revenue in € million




Energy intensity (ratio of energy consumption to revenue) in Wh/€




(1) The increase in electricity consumption is attributable to an expansion in data collection due to the inclusion of additional sites and companies (Strato and Versatel).

(2) Conversion factors/calorific values: gasoline: 8.5 kWh/l; diesel: 9.7 kWh/l. The decline in fuel consumption in 2020 and 2021 is due to the restrictions caused by the COVID-19 pandemic and to the new Guidelines on Working from Home introduced at the Company.

Electricity Consumption in Our Data Centers

IONOS Holding’s high-performance data center operations are georedundant, making the services we provide to our customers as secure and reliable as possible. This approach ensures that power outages and environmental factors do not affect the operation of the applications concerned, and gives our customers unconstrained, permanent access to them. This added reliability comes at the cost of increased electricity consumption, which we address by using renewable energy and constantly improving our energy efficiency.

Climate Neutrality and the Use of Renewable Energy

  • NfS: Use of Renewable and Nonrenewable Resources

We have used electricity from renewable energy sources for our data centers in Germany for more than a decade now. Green electricity is now the main source of supply for our locations in all countries. We only still use certificates to offset carbon emissions at a few locations, or if there is no alternative for technological or organizational reasons. As a result, we are able to operate IONOS Holding’s and 1&1’s data centers climate-neutrally. All 1&1 Mail & Media Applications SE’s servers in Germany are run at IONOS data centers, meaning that regular operations of these as well as of IONOS’s servers are climate neutral. Using renewable energy from nearby geographical areas – mostly in the same country or an adjacent region – is another priority. What is more, IONOS has been a certified VMware Zero Carbon Committed Partner since the end of the 2021 reporting period. This initiative honors cloud providers that have undertaken to develop their services in an emissions-free manner and to only power their data centers with renewable energy by 2030.

  • NfS: Nonfinancial Key Performance Indicators

The following table shows the electricity consumed in our data centers and other data centers belonging to the Group, along with the carbon emissions that we avoided.

Electricity consumption and carbon emissions for
data centers(1)




Electricity consumption in MWh




Energy intensity (ratio of electricity consumption to revenue) in Wh/€




CO2 equivalents in tonnes(3) (Scope 2)




Avoided CO2 equivalents in tonnes(4)




(1) The figures refer to our 10 own and our rented data centers; they relate to the data centers for IONOS, Arsys, Fasthosts, and Strato, plus the data centers for IONOS Cloud,, InterNetX, and World4You. Electricity consumption for 1&1 AG’s data centers is included under the energy consumption data for its office buildings, since it is not currently possible to capture consumption separately.

(2) The reduction in electricity consumption in the reporting period 2020 is due to a number of factors; see the section entitled “Increased energy efficiency”

(3) Climate-neutral thanks to the mix of renewable energy sources and carbon offsets. The figures for CO2 equivalents show the contribution made to the greenhouse gas effect. In addition to CO2 itself, they comprise other greenhouse gases such as methane and dinitrogen monoxide.

(4) Approximate figure calculated on the basis of the average annual and country-specific CO2 emissions per kilowatt-hour of electricity consumed; emissions from the electricity mix in the various countries are falling over time, due among other things to the growing proportion of renewable energy used.

Managing Consumption with an ISO 50001-compliant Energy Management System

In 2018, we took the decision to introduce an energy management system (EnMS) complying with ISO 50001. This EnMS covers the IONOS and Strato data centers that we operate ourselves and in which we can therefore manage energy consumption. Using it allows us to continuously pursue our goals of increasing energy efficiency and ensuring transparency. As a result, the EnMS helps identify and remedy potential energy wastage, hence cutting costs, and to identify and comply with external requirements such as regular energy audits. In this way, it makes an important contribution to sustainability management and can have a positive impact on our reputation and market position. The EnMS was successfully audited and certified in 2021.

The head of TechOps Hosting at IONOS and the Data Center unit manager at Strato are responsible for the EnMS and its strategic focus. In addition, a designated energy manager ensures that the EnMS is aligned with our targets, and manages the Energy Team. The latter comprises the regional staff responsible for this topic at the IONOS and Strato data centers in the various countries concerned (Germany, France, Spain, the United Kingdom, and the USA). In addition, a management system manager has been appointed.

Increased Energy Efficiency

  • NfS: Use of Renewable and Nonrenewable Resources

The air conditioning system at the Logrono data center in Spain was successfully renewed in 2021. As a result, we already made energy savings of 10% in the reporting period. 2022 will see the commissioning of our new, high-performance data center in the Birmingham region of the UK. This will replace the existing UK data center in Gloucester in the coming years. The project aims both to increase capacity and to enhance operational efficiency in the United Kingdom. Current plans expect an improvement in energy consumption of at least 20% in comparison to the existing data center.

In addition, we are implementing a continuous stream of projects and measures to reduce electricity consumption and increase energy efficiency:

  • We are steadily increasing capacity utilization per server, thus reducing the number of servers required.

  • We replace old servers with more modern and more energy-efficient hardware at an early stage.

  • Some server hardware is built to order for United Internet, allowing us to avoid unnecessary components and deploy e.g., energy-saving processors and power supply units that are designed to minimize heat losses.

  • The web hosting system used by United Internet Group companies is a highly optimized, proprietary, Linux-based system that allows data from thousands of customers to be managed on a single server, and hence optimizes our use of resources.

  • Virtualization is increasingly enabling us to replace bare metal servers by virtual servers.

  • The use of containers avoids the need for redundant operating system kernel operations; instead, the kernel is shared by all instances, enabling even more elastic, load-based scaling of the IT resources provided.

Balanced Design – The New Standard for All Future Data Center Projects

The demands placed on data centers are increasing all the time – both in terms of performance and regarding environmental aspects. The challenge for operators is to find a balance between ensuring high-availability, secure operations on the one hand, and cost and energy efficiency on the other. When it became clear in 2019 that efficiency targets at one of the Group’s data centers in the United Kingdom could not be met, constructing a new data center soon emerged as a cost-effective solution. The next step was to design this so as to offer the right combination of availability, energy efficiency, construction time, and simple, flexible operations. Structured project planning allowed IONOS to implement an extremely cost-effective data center. The new design focuses on the elegant arrangement of the technical components and is based on the concept of distributed redundancy. The latter was designed throughout in line with the Uptime Institute Tier IV classification – one of the most highly redundant operating standards in the data center ecosystem.

The new data center design also features a “pay as you grow” approach. All data centers that are newly built by us, including the one in the United Kingdom, are constructed in such a way that they can be extended on the fly at any time if needed. Only essential components are installed and operated to start with – a highly cost-effective approach. As a result, there are no excess units that have to be replaced at some point because they are showing signs of age even though they have never been used. This conserves valuable resources and saves on maintenance costs, while equipment that has not yet been installed also does not consume any power. IONOS uses this approach for large components such as UPS units, cooling generators, and cooling units. The new data center design gives IONOS a scalable, energy-efficient, state-of-the-art server and cloud infrastructure that offers high availability and an attractive price-performance ratio to match. The success of the design means it will be used as the new standard for all future data center projects at IONOS.

Electricity Consumption by Our Fiber-optic Network

Our fiber-optic network ensures economic efficiency and enables society to benefit from increasingly powerful, rapid data transfer. Today’s technology currently permits internet speeds of up to 100 GBit/s and represents the most powerful transmission technology by far. What is more, demand for higher bandwidth is constantly rising. However, since fiber optics are not available everywhere in Germany yet, 1&1 Versatel is continuing to constantly expand our fiber-optic network. Extensive additions were made to 1&1 Versatel’s network in recent years, with the addition of powerful network technology further optimizing it for our customers. Our fiber-optic network was approximately 52,600 km long at the end of the 2021 reporting period, compared to roughly 50,900 km in 2020. This continuous network expansion means that 1&1 Versatel has one of the largest and most powerful fiber-optic networks in Germany and already provides a large number of cities and municipalities with high-speed internet services.

Since 2012, 1&1 Versatel has managed energy consumption using an ISO 14001-based environmental management system (EMS). We also give reducing our electricity consumption and associated environmental impacts a high priority in our fiber-optic network operations. The measures that need to be taken to achieve this are developed on the basis of the data from the EMS.

  • NfS: Use of Renewable and Nonrenewable Resources
  • NfS: Greenhouse Gas Emissions

1&1 Versatel’s environmental management activities are centered on its major technical locations, which were identified in an ABC analysis as being the largest consumers of electricity. A substantial 49.55% (2020: 46.07%; 2019: 42.78%) of total electricity consumption was attributable to 1&1 Versatel’s 35 largest locations in the 2021 reporting period; the remaining 50.45% (2020: 53.93%; 2019: 57.22%) was distributed across approximately 2,374 (2020: 2,384; 2019: 2,334) locations owned or leased by the company.(1) As a result, the EMS is specifically deployed at these major locations in order to hit optimization targets, and to manage consumption and cost trends. The air conditioning technology in use at our major locations in Münster, Dortmund, Mainz, and Freiburg was optimized in the 2021 reporting period. We installed direct and indirect free cooling systems here that utilize cool outside air where possible for air conditioning. In addition, we installed more effective UPS systems at a number of locations. We also converted the lighting at many sites to state-of-the-art, efficient LED versions.

(1) The figures for individual locations for which no readings are currently available are based on estimates. The percentages used for 2020 were adjusted in the 2021 reporting period.

In addition to the electricity that it sources itself at its 35 largest and other locations, 1&1 Versatel is connecting its fiber-optic network with fiber-optic networks and colocation sites belonging to well-known regional city carriers and network operators and, to an increasing extent, with Deutsche Telekom’s BNGs (Broadband Network Gateways). In these cases, 1&1 Versatel does not manage electricity purchasing itself.

  • NfS: Nonfinancial Key Performance Indicators

The following table shows 1&1 Versatel’s electricity consumption and the locations where 1&1 Versatel is a user.

Electricity consumption and carbon emissions for the fiber-optic network(1)




Own electricity consumption in MWh(3)




Electricity consumption at business partners caused by 1&1 Versatel(3) in MWh




Total electricity consumption in MWh




CO2 equivalents in tonnes (Scope 2; own electricity consumption)(4)




CO2 equivalents in tonnes (Scope 3; electricity consumption caused by 1&1 Versatel)(4)




Total carbon emissions in metric tonnes




(1) The figures cover electricity consumption for all 1&1 Versatel’s technical locations, plus locations where 1&1 Versatel is a user. The electricity consumption figures for 2019 also include electricity consumption at 1&1 Versatel's office locations, since this data was not available separately. Electricity consumption is not increasing despite the expansion of the network, as it is being steadily reduced by efficiency measures.

(2) The figures for individual locations for which no readings are currently available are based on estimates; there is a delay before the data for energy consumption given for the years in question is allocated to specific time periods due to fluctuations in the reading and billing dates. Consequently, figures for prior periods may change after the report is published.

(3) A proportion of the energy used is green energy (2021: 21,147.99 MWh). This figure has not been disclosed in a separate line since it was not possible to perform a breakdown for the previous years.

(4) Estimate based on the data provided by the Umweltbundesamt (the Federal Environmental Agency) for CO2 emissions per kilowatt hour in the German electricity mix (2019: 474 grams; 2020: 401 grams; 2021: 366 grams). Actual emissions are lower due to the use of green electricity, although the proportion attributable to the latter cannot be quantified exactly.

Energy Consumption by Our Office Buildings

  • NfS: Use of Renewable and Nonrenewable Resources
  • NfS: Nonfinancial Key Performance Indicators

Our office buildings account for a comparatively small proportion of our energy consumption. In addition, a significant share of the electricity purchased in the reporting period was certified green electricity, something that reduces the potential environmental impact.

Energy consumption and carbon emissions for office buildings




Electricity consumption(1) in MWh




Heating consumption (natural gas and heating oil)(2) in MWh




Total energy consumption in MWh




CO2 equivalents from electricity consumption in tonnes (Scope 2)




CO2 equivalents from heating consumption in tonnes (Scope 1)




Total carbon emissions in tonnes(3)




(1) The figures relate to the offices and related infrastructure at United Internet’s locations in Montabaur, Karlsruhe, and Munich, which are supplied directly by the utilities concerned. They also include Vienna and the 1&1 AG locations in Maintal, Krefeld, Dresden, Nuremberg, Munich, and Münster, and the United Internet locations in Düsseldorf and Hamburg as well. The figures for the 1&1 AG companies also include electricity consumption by the 1&1 AG data centers (this data has not been disclosed separately to date). Not all figures were available by the editorial deadline for this report.

(2) The figures relate to the Montabaur location including the logistics center plus the 1&1 AG location in Maintal (natural gas) and one location in Karlsruhe that uses heating oil. Not all figures were available by the editorial deadline for this report.

(3) Calculated using the utilities’ data on CO2 emissions per kilowatt hour, the conversion factors provided by DEFRA (the UK’s Department for Environment, Food and Rural Affairs) for 2019, 2020 and 2021 and the data provided by the Umweltbundesamt (the Federal Environmental Agency) for CO2 emissions per kilowatt hour in the German electricity mix (2019: 474 grams; 2020: 401 grams; 2021: 366). Green electricity, which does not result in any CO2 emissions, was used in some cases.