Who We Are


We are an energetic and committed team of professionals, sharing our knowledge and experience to offer tailored energy and sustainable infrastructure concepts and solutions to our clients.



Rollie Armstrong

Group Managing Director
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As one of our Managing Directors, Rollie is focused on developing and implementing growth opportunities in the rapidly evolving market of renewable energies.

Prior to founding CRONIMET Mining Power Solutions (today O&L Nexentury), Rollie co-founded and served as a director of SOLEA Capital GmbH, an internationally active PV development, investment and transaction structuring company. Under his leadership SOLEA successfully developed, built, operated and transferred utility scale PV projects throughout Europe and South Africa.

As the responsible manager of a Munich based private equity group, Rollie profitably executed investments in the renewable energy sector. Further, Rollie spent six years with Ernst & Young Germany as a Corporate Finance and M&A Manager.

Rollie earned an MBA in Corporate Finance from Northeastern University in Boston and holds an undergraduate degree (B.Sc.) in Financial Services from UNLV, in Nevada.

Steffen Kammerer

Group Managing Director
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Besides his general management focus, our Managing Director Steffen is responsible for transaction- and project management, project financing and structuring of energy projects worldwide.

The business lawyer with degrees from the HFWU Nürtingen and the University of Economics Bratislava started his career at the international consulting company Ernst & Young in the area of mergers & acquisitions with a specialization in financial and advisory services to banks.

For an international investment company Steffen further actively led a considerable number of transactions and financing deals in the field of renewable energies.

In his previous role as Co-Founder and Director of SOLEA Capital GmbH, Steffen successfully managed the international expansion of the SOLEA group into Africa and Australia.

Bernd Walbaum

Group Managing Director
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Bernd graduated with his Master’s Degree in Business/Managerial Economics at the University of Hamburg in 1980. After working in the printing and media business as Sales and Marketing Director and Managing Director in Germany, Great Britain and USA and later as Management Consultant for Ernst & Young, he then served as Managing Director at Helion Solar, Germany and Solsquare, South Africa for five years. As from 2012, Bernd Walbaum is the Chief Executive Officer of O&L Energy and since August 2020 also Group Managing Director of O&L Nexentury GmbH.

A team of experts crafting efficient solutions


Nkosi Nkube

Executive Director Nexentury SA
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Nkosi serves as O&L Nexentury South Africa’s Executive Director. He gathered extensive experience in the sourcing and implementation of financial transactions while working for financial institutions and specialist advisory boutiques including Old Mutual Specialised Finance, Nedbank and Basis Points Capital. Prior to his directorship at O&L Nexentury, Nkosi was a co-Director at SOLEA Renewables (Pty) Ltd (SA), a subsidiary of SOLEA Capital. Nkosi has gained years on domestic development and project execution experience in the renewable energy sector and continues to drive new project development opportunities for O&L Nexentury.

As Executive Director of O&L Nexentury’s South African Team, Nkosi is responsible for the organization of the corporate management, project coordination as well as financing in our South African subsidiary.

Sabrina Steinhauser

General Manager: Corporate & Finance
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Sabrina heads our corporate team at O&L Nexentury. Committed to ensure a steady organizational development, Sabrina manages O&L Nexentury’s international subsidiaries and teams as well as the coordination of international projects.

She therefore directs the company group’s operations on a daily basis, including overseeing strategic execution in critical areas such as marketing, workforce development, project management, accounting, finance, and business administration. As a member of the board, Sabrina is involved in forward-thinking business stewardship and roadmaps.

Sabrina earned a M.A. in International Business with focus in Marketing from the University of Applied Science in Kufstein, Austria and holds a Bachelor’s degree in Economical Geography from the Ludwig-Maximilians-University in Munich.

Dr. Georg Wirth

Technical Director
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As head of our technical department, Georg is responsible for the coordination of the technical feasibility studies, engineering analyses and procurement as well as for the development of hybrid PV, Diesel and energy storage system designs. Prior to joining O&L Nexentury, Georg led the photovoltaic grid integration team at the University of Applied Sciences Munich’s solar energy lab since 2010. During his four year stint, Georg managed a number of complex grid stability research projects outsourced to his lab by companies such as E.ON, General Electric, Siemens, and research institutions including the Technical University of Munich, DLR, and the Fraunhofer Institute.

Georg’s educational background started with a training at Siemens across the electrical engineering division. Georg achieved his Ph.D. Degree from the Carl von Ossietzky University at Oldenburg on modelling the meteorological effects of grid distribution physics under high photovoltaic penetration scenarios.

Wilko Duvel

Financial Director
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As head of our financial department, Wilko is responsible for the finance function at Nexentury Group.

Prior to joining O&L Nexentury, Wilko was the Head of Finance at Namibia Dairies.  In this role he formed part of the senior leadership team for Namibia Dairies, and was therefore part of the strategic decision-making team affecting the long-term direction, actions and viability of the company as a whole.  During his tenure at Namibia Dairies, he has successfully improved the workings, structure and compliance within the procurement department.

As a registered Chartered Accountant, he has audited companies within the insurance, agricultural, retail and manufacturing industries.  Gaining international experience in a secondment to PWC Zürich, Switzerland has provided him with broad exposure and experience in the financial sector.

Luc Tanoh

Senior Project Advisor
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Bringing over 30 years of experience in the Telecom, IT, Power Utility and Engineering industries throughout Africa, US and Europe to O&L Nexentury, Luc is a highly regarded Senior Executive, GSM and Energy specialist, combining significant board-level experience with in the field regional and continental leadership roles .

As Head of West Africa, Luc is responsible for business and project development throughout West Africa and the Francophone regions of Africa. He holds a Master’s Degree of Sciences in Electrical Engineering from the Swiss Federal Institute of Technology and a Master’s Degree of Sciences in Industrial Engineering and Operations Research from the University of Berkeley in California.


Mladen Savic

Project Associate
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Mladen is our Senior Financial Analyst and is responsible for project finance, financial modelling, project controlling and all other quantitative analyses surrounding our projects.  

Mladen earned his Bachelor’s degree in the United States at Georgia State University, in the field of Economics and Finance. He moved to Germany in 2015 to pursue his Master’s degree at the Ludwig-Maximilian University in Munich. He joined the company in 2017 as a working student, where he was first exposed to the renewable energy sector and project finance.  

He graduated from Ludwig-Maximilian University in 2018 with a Master of Science degree in the field of Economics. Mladen has since deepened his skillsets in the areas of project finance and financial modeling enabling him to grow into his current role at O&L Nexentury. 


Eliaser Nikodemus

Project Associate
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Peter-John Christiane

Technical Manager
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Coming soon…

Heather Meletzky

Junior Financial Analyst
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As a Junior Financial Analyst, Heather adds value to the Nexentury team through comprehensive financial support in all aspects of the project management chain, with a primary focus on extensive financial and investment analyses of renewable energy projects.

She collects, collates, and analyzes data in order to develop and optimize financial models/projections.

She has a background in corporate banking and project finance, and holds a Bachelors Degree in Economics from Stellenbosch University.

Lonwabo Ntshiba

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As Junior Draftsman at O&L Nexentury SA (Pty) Ltd, Lonwabo supports our technical team and assists in O&M services, yield assessments and the drawing of PV plant layouts. He holds a national diploma in Mechanical Engineering from the Cape Peninsula University of Technology and started his BTech in Mechanical Engineering at the University of South Africa. With previous trainings in Engineering at the Two Rivers Platinum Mine and the Grinaker-Ita Mining, Lonwabo has built his background in the renewable engineering and mining industry.

Michaela Hilfinger

Project Assistant Germany
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Coming soon…


Chanté Smith

Project Assistant
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Chante assists the Technical Project Manager in project planning, development and managing the completion of various commercial Solar PV projects from design to implementation within the scope, schedule and budget of the projects. She also assists in the adjudication and coordination and management of the subcontractors of the projects.

She provides support to the legal department as well as contract administration.

Chanté is currently completing her Bachelor of Laws at the University of South Africa and has considerable knowledge in Contract Management, specific to the FIDIC and NEC Contracts.

Nathalie Schröder

Office Manager
Coming soon…

Jenna van der Wath

Team Assistant SA
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Within her role as a Team Assistant, Jenna performs a variety of administrative and accounting tasks.

She provides support to managers and employees and assists in managing company’s general administrative activities, which includes but is not limited to, office procurement, travel management and preparatory accounting.

With her dedication and proven ability to establish and maintain excellent communication, Jenna also provides administrative support in Marketing and Project Management.

Vera Späth

Team Assistant Germany
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Vera is employed as team assistant at the O&L Nexentury office in Eschbach (Germany).  

She is responsible for all office and administrative tasks, as well as for office and administrative support for the German headquarters in Starnberg. This includes all administrative and organizational activities as well as preparatory accounting. 

In addition, she plans and organizes travel activities for managers and employees at the German locations and organizes corproate and team events.


Beaulah Gabriel

Administrative Clerk
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Beaulah serves as Administrative Clerk at OLC Energy Services (PTY) LTD, a subsidiary of O&L Nexentury in Namibia. She performs a wide variety of office support and clerical duties and activities. She supports the finance and accounting department, sales and distribution and manages the inverter warehouse.

Walking the walk in all we do