The greentech Management Board.
Act with foresight, manage successfully, grow together
The greentech Group is led by an experienced management board. It is formed by five managing partners.
The Management Board
Ingo Rehmann
Chief Executive Officer (CEO)
In addition, Ingo Rehmann heads the Project Development division and oversees Group-wide project development of photovoltaic and battery storage solutions through to ready-to-build status across greentech’s core markets in Germany, the United Kingdom, and Italy. He also leads the Central Services, which act as an internal service provider bundling key cross-Group functions such as Accounting, Human Resources, Corporate Development, and IT Services.
Ingo Rehmann has been active in the PV industry since 2005. He held various management positions at Conergy AG, including in the areas of M&A and as Head of Market Intelligence. In 2008, he founded greentech and developed the company into one of the largest independent PV O&M and engineering companies in Europe. He studied Business Administration in Germany, Australia and Spain.
Aleksis Schäfer
Chief Financial Officer (CFO)
As CFO, Aleksis Schäfer is responsible for Corporate Finance & Corporate Controlling, Corporate Accounting and Data Science. Together with the CEO, he is also responsible for reporting to shareholders and stakeholders.
Aleksis Schäfer joined greentech in 2010 and, among other things, was responsible for setting up the Asset Management division. He has been active in the PV industry since 2005, where he initially gained experience in post-merger integration at Conergy AG. In 2008, he joined the Boston Consulting Group as a management consultant. Aleksis Schäfer studied Business Administration at RWTH Aachen University and holds a Master's degree in Engineering Physics from Helsinki University of Technology.
Joern Carstensen
Chief Technical Officer (CTO)
In his role, Jörn Carstensen combines the management of all technical areas of the greentech group. As CTO, he is responsible for plant construction, engineering services and technical management. The aim is to create uniform standards and processes across all technical areas at greentech, thereby ensuring company-wide synergies, high quality and the greatest possible transparency.
Jörn Carstensen joined greentech in 2014 as Business Development Manager. In addition to developing various European markets, he built up the Engineering and Technical Advisory division. From 2006 to 2014, he worked for the Conergy Group in various international corporate and business development positions. Prior to that, he worked for a consulting unit of Accenture and supported utility companies in strategic and organisational issues. Jörn Carstensen holds a degree in Industrial Engineering with a specialisation in Energy and Environmental Management from the Universities of Flensburg and Southampton.
Jacob Isenberg
Chief Investment Officer (CIO)
Prior to joining greentech, Jacob Isenberg served as CFO of E.R. Capital Holding, of which greentech is a part. Through his time at E.R. Capital Holding, he is well acquainted with greentech and with the market and business environment of the renewable energy sector. Earlier in his career, he worked, among others, for Hapag-Lloyd, Accenture and a HealthTech start-up, bringing experience in corporate and asset finance as well as strategy across a range of corporate settings.
Jacob Isenberg lives and works in Hamburg. He studied in Milan, Singapore and Hamburg, and holds an M.Sc. in Economics, Politics and Management from Università Bocconi (Italy).