Energy efficiency in industry and production

How to supply a high-performance computer centre with CO2-neutral cooling energy

First biomethan-refrigeration supply for companies belonging to the e-Plus group, Düsseldorf
Over the past 20-plus years, enercity Contracting GmbH (eCG) has been operating what is now more than 1,300 power stations in Germany. The spectrum of systems which are being tended range from energy supply from boilers with a minimum 100 kW heat output to multi-boiler and steam-generating plants above 10 MW. Large heating networks and complex power stations are also in the mix. eCG is reliable in providing not only heat, but also cooling energy and electricity to its customers. The E-Plus Group (E-Plus) has been operating a computer centre on Parsevalstraße in Düsseldorf since 1996. The centre offers services which include IT assistance for all of the branches from the group and data retention for what has come to be over 22 million customers. Since autumn 2012, the computer centre has been in compliance with the TIER III high-security criteria. This is in no small part thanks to a newly constructed energy centre which eCG helped build and now operates. Through the use of self-produced biomethane and an innovative overall concept, the energy which is needed to operate the power station is CO2-neutral.

View of the ECG biogas system with biomethane processing in Giesen, Lower Saxony

View of the two biomethane-operated combined heat and power units in the energy centre for the computer centre of the E-Plus group

Trigeneration
The energy centre provides both cooling energy and – in the case of power failure – electricity with an N+1 redundancy. To cool the computer centre (cooling load approximately 2.5 MWth), there is always cooling energy available by means of free cooling, ultra-modern turbo-compressors or an absorption refrigerator with more than 6 MWth of overall performance. To power the absorption refrigerator, two large, biomethane-powered combined heat and power units that are capable of isolated operation are required for the turbo-compressors. The combined heat and power units are also needed for other important electricity consumers in the energy centre. A capacity of more than twice the required amount is available for both the supply and return of cooling energy. The specific cooling capacity is about 1,620 W/m².

High-security computer centre in accordance with TIER III/IV
The computer centre of the E-Plus Group is subject to the highest quality and availability requirements according to TIER III/IV. Having double supply channels for the production, distribution and utilisation of the cooling capacity as well as the highest standard possible (TIER IV) enables maintenance during operation and a guaranteed annual availability of 99.995%. Should the public utilities’ electricity network fail, complete N+1 redundancy is also available: two independent diesel-powered UPS systems supply the computer centre, while the energy centre can maintain refrigeration by drawing on the energy of at least one of the two biomethane combined heat and power units.

Security thanks to energy supply contracting
Despite the high availability requirements, the early integration of eCG as a contractor for E-Plus has not resulted in a need for any additional personnel or large investments. The long-term energy costs are easy to plan. Thanks to special incentive and premium-based arrangements in the contract, it is assured that the power station will be operated in a secure manner and that resources will be used consciously. Fault and error messages run simultaneously and redundantly to an automated control system and are accumulated directly in eCG, thereby enabling extremely quick reaction times.

CO2-neutral, highly efficient operation
The energy concept which has been realised shows foresight with regard to the possibilities of “Green IT”: on the one hand, combined heat and power units cover the complete electricity, heat and cooling requirements of the power station, while on the other, CO2-neutral biomethane is used as input energy for the combined heat and power units. The highly efficient combined heat and power enables more than 83% of the primary energy to be used. The latest turbo-compressors and a sophisticated optimisation system use the electrical energy that is available with a high degree of efficiency.

Self-produced biomethane provides planning security
Using renewable raw materials, an eCG-owned biogas plant in Giesen is producing biogas which is then dried, desulphurised and refined to biomethane in a processing plant. By feeding the biomethane into the public gas network, it can be extracted throughout the country and efficiently used – as is the case with E-Plus and its combined heat and power units. Were there to be an unanticipated expansion of the computer centre, long-term contracts with farmers and the high system capacity would provide ample planning security for the supply of renewable energy.

contact details/company:
enercity Contracting GmbH (eCG)
Glockseestr. 33
30169 Hanover
Customer E-Plus Mobilfunk GmbH & Co.KG

contact person:
Matthias Einax
Project Manager, Sales Representative (eCG)
Phone: +49 (0)511 430-1844
Fax: +49 (0) 511 941430-1844
matthias.einax@enercity-contracting.de

Peter Tiggelkamp
Head of Data Center
0211 448-4350
peter.tiggelkamp@eplus-gruppe.de