About us

Do you know any athletes who are among the best in the world in all sports? It’s not likely. And what is true for athletes also applies to recruitment consultants. After all, nobody can have detailed knowledge in many industries simultaneously, be on the cutting edge of developments and also be able to draw on an extensive and in-depth candidate network. That is why we deliberately focus exclusively on the energy sector. And in all modesty, we really know what we’re doing here. We have successfully completed more than 300 projects over the past seven years. The experience we have gained from this and our network greatly accelerates the search for candidates: While others are still trying to understand the task, we are already delivering the first results.

As helpful as knowledge of the industry and a great candidate network are however, they do not replace the need for the curious listener. After all, the decisive factor is often hidden behind what is obvious. This applies to the task presented by our clients as well as to the selection of candidates. We are well aware of our responsibility to our clients in this regard. Our pursuit of excellence extends to all the process steps in our consulting projects and serves only one purpose: finding the best candidates and rather than the second best. Maximum discretion and confidentiality as well as great sensitivity in dealing with candidates and companies are a matter of course for us.

Partner, Authorised Signatory

Kaspar Klostermann

Kaspar is a founder and partner of Callidus Energie. As a student of business administration at the Justus-Liebig University in Giessen he already worked for various management and recruitment consultancies before finding his way to Callidus after obtaining his business degree. Mr. Klostermann now has seven years of experience as a recruitment consultant in the energy sector, where he has supervised mandates in the areas of strategy, finance and energy networks in particular.

Knowledge Manager

Julia Leonhardt

Julia is a knowledge manager at Callidus Energie. While studying education at Goethe University Frankfurt, she was already working for various management and personnel consultancies. After completing her studies, Ms Leonhardt worked for six consecutive years as a research associate at one of the world’s leading executive search firms. At Callidus Energie, she supports the consultants in their search for and selection of suitable leaders as well as in further developing sourcing methods.


Jonathan Lichter

Jonathan is a founder and partner of Callidus Energie. While studying business administration specialising in business informatics at the University of Mainz, Mr. Lichter started working in the field of executive search at a leading recruitment consultancy. In the last six years, he has held challenging mandates in the areas of sales and digital transformation. His solid network now ranges from managers to strategists to highly specialised top performers in the energy sector.

Jonathan is also interested in futuristic topics in his private life: as a “digital native” he passionately pursues all sorts of technological trends and developments. He is thus not only responsible for all IT topics at Callidus, but also plays a decisive role in the company’s development.


Anja Neubert

Anja supports partners in their sales activities. She coordinates all appointments while keeping track of all activities and the growing network. After completing her A levels and then training as an administrative assistant, Ms Neubert worked for about 15 years as a project manager at a major event agency.

Partner, Leiter Eignungsdiagnostik

Ralf Sundermeier

Ralf is a partner at Callidus Energie who is responsible for the development and application of selection procedures that are based on aptitude diagnostics. A qualified psychologist and state-certified business economist, Mr Sundermeier has more than 10 years of management experience; among other things, this includes serving as the human resources manager of a large German bank. Thanks to his many years of experience as a consultant and coach, he has extensive experience in personnel selection, overseeing transformation processes and developing high-performance teams.

Managing Director

Ron-Arne Sydow

Ron-Arne is a founder and managing partner of Callidus Energie. The graduate business economist already gained his first entrepreneurial experience in his youth and has been working in recruitment consulting for over ten years. In addition to his top management level positions, he supervises mandates in the area of decentralised energy solutions, where he maintains an intensive network. His area of special interest is aptitude diagnostics. He is a keen observer of the processes of change in the energy sector and is a regular speaker on personnel policy topics.

His personal passions are having discussions about social and political issues as well as playing the piano. He is an enthusiastic snowboarder and looks forward to those cold winter days just like some of his clients.


Markus Tittmann

Markus is a founder and partner of Callidus Energie. After studying social sciences at the Justus-Liebig University in Giessen, he gained his first experience as a recruitment consultant at a renowned executive search company. In the last six years, he was able to build up an extensive network and expertise in the field of renewable energies and primarily supervises mandates in this area.


Head of Office Management

Katrin supports the partners in the operational area and takes care of all organizational tasks. She is the contact person for many administrative topics, such as Marketing and accounting.

She has worked as a secretary and project manager in law firms and advertising agencies. With experience from various fields and her studies in business administration (FH) she successfully steers large and small projects.