The Architecture project of the ECREEE (Ecowas Centre for Renewable Energy & Energy Efficiency) headquarters, located in Palmarejo Grande Frente, City Of Praia, Santiago’s Island, presents a rectangular format area corresponding to 8061.00 m². ECREEE was created in November 2009 by the ECOWAS Commission, supported by Austrian and Spanish government and technically assisted by UNIDO. The ECREEE’s main objective is to support the development of the renewable energy market and energy efficiency is West Africa, supporting several activities to mitigate the existent barriers. The architecture concept of the ECREEE’s headquarters project is based in two basic aspect of sustainability: the Passive and Active Architecture, and the main intended objective is to develop a building, able to maintain an ideal environment for working, with the temperature always 2 degrees below the local external annual average, with total or almost total energy autonomy, gray and rain waters recovery. To reach the passivity prerequisites, the building implementation in “U” shape, oriented to south, and provides protection against strong northeast winds and intense sun light. But, by a need of sea view relation, the initial “U” shape, receive torsion, closing slightly the interior courtyard and providing a huge relation with the sea, at the same time create a sheltered courtyard protected from the sun light and the wind, with a vast sea view to south. In this area will be located the open-air auditorium. The building Adaptation to the ground develops in two levels, to allow the access and the quota threshold at the same CERMI level. The “U” bottom, to north, stands to allow the entrance and the main hall in the upper level, the working offices stays at the lower level adapted to the native land. The Wall Protection System and double coverage, serves as “hat” of building protection, that makes the air circulation to be done by outside, like air chamber of natural cooling, protecting the interior from the strong winds, dust and minimizing the solar radiation. The Mixed Ventilation system like Badgir or Wind Tower, inspiring in one of the traditional architect element of the Middle East, the “Badgir” or “Wind Tower”, is a system that consists in the high level exterior air entry (tower), to the basement through low chambers for particles depositions (specially sands), circulating air through air-corridors in spiral at the basement using the soil temperature to cooling the air and after inflate to the occupied areas (offices). The Rain water reuse, collected by the courtyard coverage and thereafter stored in underground tanks for plants and gardens irrigation, reducing the water consumption of the building, and recycling of the grey waters, will allow to reduce the water consumption in the plants and gardens irrigation. Wind and Solar power, the ECREEE’s headquarters has a set of Photovoltaic Panels and Wind turbine installed for electrical energy production. It’s a clean and silent process that dismisses regular maintenance.