Contact us

Ecofys WTTS

PO Box 8408

3503 RK Utrecht
The Netherlands
+31(0)30 662-3827



Michiel Müller, managing director

Michiel MullerMichiel Müller (1963) is Managing Partner Energy Systems & Markets and Managing Director of Ecofys Wind Turbine Testing Services (WTTS), and has been working at Ecofys from 2008. After receiving his doctorate degree in Physical Chemistry from the University of Amsterdam, The Netherlands, in 1990, and several post-doc positions, Michiel Müller became Assistant professor in 1999 and Associate Professor in 2002 in non-linear optics and biophysics at the University of Amsterdam. During this time he also held visiting scientist positions at two Universities in the USA. Throughout his academic career Michiel Müller published more than 60 papers in peer review journals and held numerous presentations at international conferences.

In 2008, Michiel Müller made a major career switch to the field of sustainable energy and became senior Researcher & Developer in the 'Innovation' division of Ecofys. He was made responsible for the sea water air-conditioning (SWAC) development programme, which concerns both the technical and financial issues for SWAC project development. Under his supervision financial assessment, SWAC system optimisation and control strategy approaches have been developed and executed. In addition he has undertaken various initiatives within the innovation field of heat & mass transfer and bio-energy. He was part of the management team of the ‘Innovation’ division.

In November 2009 Michiel Müller joined the Wind Energy department of Ecofys as Senior Consultant, working as project leader for the Far and Large Offshore Wind (FLOW) programme. He was also involved in business innovation within the wind energy portfolio. Michiel Müller was one of the project developers of the wind turbine test facility near Lelystad, which became operational in 2011. Michiel Müller is now the Managing Director of Ecofys WTTS which co-ordinates all activities at Test Site Lelystad and provides all required measurement services to the turbine manufacturers.

Michiel Müller headed the Wind Unit of Ecofys from 2010 and is currently the business area manager of Energy Systems & Markets, which covers large scale renewable energy generation, as well as energy infrastructure and market design and regulation.


Maarten Graveland, site manager

Maarten GravelandMaarten E. Graveland (1976) is technical engineer at Ecofys and site manager for Test Site Lelystad. He studied mechanical engineering in the field of control techniques. He has a wide range of practical working experience in the field of production, quality control and electro-mechanics.

Since 2006 he is working in the field of energy efficiency and renewable energy. As off 2007 he is working at Ecofys, especially on product and project development in renewable energy (solar thermal, solar PV, heat recovery, wind energy and biogas). His personal quest for energy efficiency is visible in his projects on monitoring, data transmission and analysis/visualization of energy flows and systems. These projects include monitoring of universities complex energy consumption, energy audits in international ports and creating quality statements on district heating networks.

On Test Site Lelystad, Maarten liaises between our customers -the turbine manufacturers- and the land owners. He focuses on an effective execution of construction works of wind turbines and met masts. Within WTTS he is responsible for the installation and maintenance of LiDAR and SoDAR wind measurement machines. Either our own or our clients’. For validation & verification at our own Testpad or for measurement campaigns elsewhere in Europe.