Management Board
Management of the Data Center Group

Ralf Siefen

CEO / Chairman

Ralf Siefen, Chief Executive Officer, founded the Data Center Group in 2005 under the name proRZ Rechenzentrumsbau GmbH and built it up into one of the market-leading companies for the consulting, planning, construction, service and operation of data centers. Today, the company employs around 200 people and can look back on more than 2,500 national and international projects. He gained his expertise in the planning and realization of data centers in during his professional career with the company Lampertz. There he was responsible for national and international project management for more than 12 years as a member of the management board.

As before, his great passion is the design of secure, efficient, highly available and sustainable data centers that are future-oriented and adapt to the needs of small and medium-sized enterprises up to corporations and hyperscalers.

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Data Center Group CEO Ralf Siefen
Picture Philipp Riemen, Commercial Director DCG, standing. smiling

Philipp Riemen


Philipp Riemen is Chief Finance Officer of the Data Center Group and is responsible for the commercial areas of the company. Mr Riemen studied business administration at the University of Bayreuth. 

After graduating, Mr Riemen worked in corporate finance/M&A consulting for around 15 years. In 2012, he moved from the consulting side to the corporate side at MVV Energie AG. There he initially headed the Mergers & Acquisitions department. Subsequently, as Head of Finance & Investor Relations, he played a key role in positioning MVV on the capital market as a strong company with a strategy consistently focussed on sustainability.

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Markus Böhmer


Markus Böhmer, Chief Technical Officer and thus responsible for the coordination and responsibility of all strategic and operational tasks of the company, is a man of the first hour at the Data Center Group.

Previously a project manager at Lampertz, specialising in international project management, he also worked at the Data Center Group for over 7 years from 2005. He was then Head of Project Management for almost 8 years. Most recently, as an authorised signatory, he was also Head of Engineering and Project Business at DCG. His focus here was on the further development of efficient project management and the optimisation of cooperation between planning and execution.

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Markus Böhmer, CTO Data Center Group, with crossed arms