Green-IT in the data centre
What potential does the UPS system offer?

With the Leipzig 2 data centre, envia TEL GmbH relies on quality and safety made in Germany and thus offers its customers high availability combined with resource-saving operation.

Driven by digitisation, the amount of data that then needs to be managed is constantly growing. IT trends such as cloud computing, artificial intelligence, metaverses and streaming are increasingly driving up the power consumption of data centres. When it comes to making data centres more energy-efficient, operators have tended to first invest in servers with processors that are as economical as possible, and in efficient air conditioning.

For some time now, there has been an increased focus on potential savings using smart power supplies. Equipped with intelligent control software, these systems continuously adapt their own consumption to the current workload of the data centre.
They are optimised to automatically set hardware that is not currently required to energy-saving mode without jeopardising the secure operation of the data centre.
They assume energy management functions, offer options for the integration of energy storage systems or the procurement of sustainably generated energy from photovoltaic and wind power plants.

Energy consumption reduced to a minimum

With the ENERTRONIC modular SE UPS system, BENNING has already established a UPS system on the market for several years that meets the requirements for resource-saving and fail-safe operation.
This software-controlled system puts UPS modules that are not required to supply the current load into a kind of “sleep mode”. In doing so, their own consumption is reduced to a minimum without restricting safe double-converter operation. If the load conditions change suddenly, the modules are activated and deliver the full load within less than two milliseconds.

99.99996 % availability

For 2 years now, 2 redundant ENERTRONIC modular SE systems, each with 1.2 MVA, have also been protecting the Leipzig 2 data centre from network disruptions.
The high-performance data centre operated by envia TEL GmbH in Taucha, just outside Leipzig is certified according to the EN50600 VK3 standard and classified as highly available.
It currently includes 1 000 m² of server space and another 1 000 m² of server space for future expansions.

UPS systems ENERTRONIC modular SE with open doors — UPS systems ENERTRONIC modular SE

envia TEL GmbH (envia TEL) is a 100 percent subsidiary of envia Mitteldeutsche Energie (enviaM) based in Markkleeberg in Saxony, Germany. This company is the leading regional telecommunications service provider and network operator in Central Germany and offers products and services across the entire spectrum of telecommunications, services for network operators and cyber security solutions.

Using the data centre campus Leipzig, envia TEL operates one of the most modern data centre locations in Europe and offers space for 60 000 servers on an area of 3 000 square meters.

The services focus on housing, hosting, cloud services and collocation. The customer structure is diverse. It includes companies from the industrial and infrastructure segments as well as from telecommunications. Some of them have outsourced their entire IT to the data centre. These customers rely on the high availability guaranteed by envia TEL, because a failure would significantly affect the entire business operation and could cause enormous economic damage.

From this, we can draw the following conclusions with regard to power supply systems: The guaranteed availability of the UPS system is the most important quality feature. How reliable they are depends largely on the reliability of the modules used. The topology and the way the modules are configured, however, are equally important.

The ENERTRONIC modular SE achieves an outstanding availability of 99.99996%, often referred to as “six-nine” reliability. This corresponds to a maximum downtime of less than 13 seconds per year.

Six-nine reliability

Due to the high number of system components in a modular UPS system, we assume a Mean Time Between Failures (MTBF) of 500 000 hours in our equation below.

However, since each UPS module in this topology represents a complete and fully functional power supply system that can be hot-swapped in less than ten minutes while the entire system is in operation, the Mean Time To Repair (MTTR) is one very impressive value of only 0.17 hours.

The following therefore applies to system availability:

Availability = MTBF / (MTBF + MTTR)

= MTBF / (MTBF + MTTR)
= 500 000 / (500 000 + 0.17)
= 500 000 / (500 000.17)
= 99.99996 %
= 0.21024 minutes / year

^{* Source: cf. detailed article on the availability calculation of power supplies in POWER news 08/2017}

Learning from experience

As the name “Datacenter Leipzig 2” implies, it is the second data centre on the data centre campus in Taucha. A few years ago, envia TEL constructed the Leipzig 1 data centre. At that time, it was equipped with diesel-dynamic UPS monoblock systems, which still supply the data centre today, still adhering to the highest availability requirements.
However, these monolithic systems have various disadvantages in terms of flexibility, energy efficiency and economy compared to current modular UPS systems.

For example, the entire capacity required for the final expansion of the data centre must be installed right from the start. This requires a comparatively higher initial investment, and the UPS systems are only used to a low extent over a long period of time. They are therefore operated outside of their optimum efficiency. The result is higher power losses and lower energy efficiency.

Holistic view

When the “Datacenter Leipzig 1” had reached about 70% of its maximum server capacity, envia TEL began planning another data centre in 2017. Based on the findings from operating the previous diesel-dynamic UPS systems, the goal was to now use modular UPS technology.

BENNING and envia TEL had already established a business relationships in the field of telecom power supplies, BENNING also received the corresponding call for bids in 2018. With commitment and a high degree of customer orientation, the BENNING project team then developed various concepts with regard to possible system configurations, flexible performance design (pay as you grow), economical operation and optimal use of space when installing on site. In extensive benchmarks, envia TEL compared both the monetary aspects of the initial installation, the total cost of ownership (TCO) and the technical parameters of the various UPS providers. Advantages and disadvantages were compared and a wide variety of scenarios were run through.

Smart system efficiency

Data centres are said to be major consumers of electrical energy. Accordingly, envia TEL wanted an intelligent, energy-efficient power supply system whose self-consumption is optimally adapted to the dynamically changing capacity utilisation of the data centre at all times.

With the user-selectable and individually configurable operating mode SEOO (System Energy Optimized Operation), the ENERTRONIC modular SE meets precisely these requirements. The system automatically and intelligently guarantees the highest system availability while having the lowest operating costs. To do this, the software continuously determines the number of modules required for safe and economical operation and puts all others into a state of controlled inactivity. Nevertheless, these modules are also permanently available in order to supply the critical load without interruption if required (e.g. in the event of a load increase).

In addition, the installed system performance can grow in parallel to the expansion of the data centre. This eliminates the risk of over-investment from day one, because the system only includes the exact number of modules that are required to achieve the maximum system performance required and to create redundancy. If the required power increases or decreases, modules can be easily added or removed (hot swap).

The UPS system is scalable and can grow as the data centre expands

Small footprint

The customer was also impressed by the power density (415 kW/m²), which is unique for this UPS class, and by the small space requirement. The entire air flow of the UPS system is discharged through the system roof, or optionally through the rear.

All settings, service and maintenance work are carried out from the front. This means that very space-saving and flexible arrangements are possible at the installation site, because the UPS systems can easily be placed back to back, lined up against a wall or in a corner.

UPS room of the company data centre Taucha — Data centre Taucha, UPS room

Decentralised parallel architecture Circuit diagram — UPS system design as DPA (Decentralised Parallel Architecture) - there is no single point of failure due to complete redundancy.

No single point of failure

BENNING was also able to score in terms of system availability. The power supply system operates as a fully redundant UPS system in which the parallel architecture of the modules has been successfully decentralised, resulting in a UPS system without a single point of failure. For this purpose, all critical components, including the bypass and control units, are located at the module level and in some cases there is additional redundancy in the design. To increase system availability, the implemented multiple master technology also enables each module to switch automatically to master or slave operation.

The monitoring and control unit (MCU) allows the system to be connected to EMS from a wide variety of software manufacturers with a large number of supported protocols and interfaces. The system controller (MCU 3000) built into the cabinet door of the power supply system has a 10.4" touch display.
This display view shows the operating status of an ENERTRONIC modular Storage.

High delivery performance

From the benchmarks and scenarios, the concept developed by the BENNING project team emerged as the winner and won the call for bids. The BENNING team was commissioned by the electrical engineering general contractor at the beginning of 2020. As early as May of the same year, the technicians from the regional BENNING service branch in Dahlewitz in Brandenburg, Germany installed the two ENERTRONIC modular SE systems and the battery strings required for the specified bridging time. The Monitoring Control Unit 3000 (MCU 3000) is used for simple, intuitive operation and remote monitoring.

Commissioning followed in June, and the systems were initially only equipped with the number of power modules actually required for the current critical load. In the future, more modules will be continuously retrofitted in line with the expansion of the data centre.

Green IT – Fit for Future

According to envia TEL, the power supply for the data centres is already 100 percent from renewable energies. Should a PV or wind power plant be integrated directly into the supply of the data centre in the future as part of the Green IT idea, this is also possible with the ENERTRONIC modular SE.

For this purpose, BENNING has already successfully established the hybrid UPS energy storage system ENERTRONIC modular Storage on the market.

It enables the integration of renewable energy sources such as PV systems, the provision of fast charging energy for electric vehicles and peak load capping, so-called peak shaving, to avoid high energy costs due to peak loads.

This is good news for all operators of ENERTRONIC modular SE UPS systems, as these systems can make full use of the energy storage functions as part of an upgrade. Consequently, envia TEL is excellently positioned for the future.