Ennesys promotes the idea to produce local resources by treating wastewater locally, by transforming waste into resources on site. By integrating this production system in buildings, no floor space is used. This approach reflects Ennesys’ profession in the heart of the energy transition and takes three major issues into account: reducing the carbon footprint, water supply and simultaneous energy production. The system uses a certain phytoplankton (micro-algae) with a distinguishing feature; they can purify water by multiplying themselves. They simultaneously represent an excellent raw material for producing energy. The system can be applied to the façade’s of the buildings in a city, to industrial production complexes, and to remote or temporary sites like refugee camps, construction sites, or any remote area lacking infrastructure, based on a mobile version of the system called FreeWaterbox.