Energy-plus, zero energy and zero emission buildings denote some of the best buildings of today and the future with respect to energy efficiency and environmental impact. A zero emission building might be defined in different ways. Nevertheless, the main concept is that renewable energy sources produced or transformed at the building site have to compensate for CO2 emissions from operation of the building and for production, transport and demolition of all the building materials and components during the life cycle of the building. In order to fulfill this, CO2 emission data has to be made available and verified for traditional…