The ‘Stuttgart 22‘ vision by LAVA architecture and Transsoalar Klimaengineering seems to be a “lower cost” approach to the planned controversial conversion of the heritage main train station in Stuttgart, Germany (‘Stuttgart 21‘ (Wikipedia) , The New Heart of Europe (official site)). This alternative study is focusing on a visible renewable energy approach in order to achieve CO2 neutrality and a compact work/live downtown environment. A 200m solar updraft tower is utilizing the stack effect of warm air rising from within a double-skin, transparent roof up through the tower in order to power a turbine. The roof as well serves as a photovoltaic plant. These combined effects are thought to be sufficient to serve the 3000 new residential units within the new development. The tower could be the visible icon of a new era. This concept was presented by Prof. Tobias Wallisser from LAVA architecture at the Creativity Worldforum in 2009 and is available to watch at zaplive.tv (follow the link and fast-forward to about 2/3 of the recording) ..