Zero energy and zero carbon buildings: myths and facts

Zero energy building (ZEB) and zero carbon building (ZCB) are general terms applied to a building with zero net energy consumption and zero carbon emissions, respectively. In recent years, ZEB and ZCB have attracted much attention in many countries because they are considered as an important strategy to achieve energy conservation and reduce emissions of greenhouse gases. In some countries, the strategy for moving by regulation to ZEB/ZCB has generated a lot of debate as to whether it is currently feasible. This research paper explains the myths and facts of ZEB and ZCB, with the aim to enhance understanding and avoid misleading statements. The definitions and key concepts of ZEB and ZCB are described. To investigate the practical considerations and real meanings of ZEB and ZCB to our society, some of the pilot projects in the world are reviewed and the local conditions in Hong Kong are studied. The critical issues for achieving ZEB and ZCB are discussed from both engineering and architectural points of view. Important factors affecting the feasibility of ZEB and ZCB are examined.