Marten Witkamp works on market transformations towards greater sustainability. He has been in this line of work since graduation in 2008, focusing mostly on the housing and energy markets, always from a drive to innovate. As a ‘Transition Practitioner’, he has taken on various roles over the course of these years, including group facilitator, researcher, initiator, and content communicator. Most recently, he has been involved with De Stroomversnelling, a nationwide collaboration between construction companies and housing corporations to renovate 111.000 homes to zero energy, using the additional cashflow of the renters’ current energy bill and radical innovation by the construction companies. On a regular basis, he works for Energiesprong and Platform31. Other partnerships are Rathenau Instituut, Regieraad Bouw, Broodfonds and of course the other companies in the Rotterdam Collective.