The net zero energy building, or zero energy building (ZEB) for short, gets supplied with electricity from an electric power company, but it generates and stores electricity by itself to reduce purchase volume considerably. Because it can sell surplus electricity to an electric power company, the procurement volume of power comes out even.
Shimizu developed a design method to reduce energy consumption to virtually zero through self-support of electricity by employing windows with high heat insulating properties and utilizing natural ventilation. The company got an order from a religious institution for a low-rise office building for about 5 billion yen. The office building is scheduled to be completed in March 2013. This building will supposedly be the first ZEB in Japan. In addition to using LED illuminations and insulated windows, the company will introduce the latest building energy management system (BEMS) for full utilization of the electricity stored in battery.
Obayashi is developing a technology to construct a ZEB that conserves energy using earth thermal whose temperature remains the same throughout the year. Takenaka has been developing the idea of carbon-minus building that supplies surplus energy to other buildings. Toda plans to construct a ZEB by 2020. It costs 30-40% higher to construct a ZBE than a standard building. Shimizu is constructing its head office building in Tokyo that reduces carbon dioxide emissions by more than 60%.
In 2009, the Ministry of Economy, Trade and Industry laid down a policy that newly buildings be a ZEB by 2030, and plans to appropriate a budget for subsidies to construct a building closed to a ZEB. The construction industry is busily occupied with the development of ZEB concepts because ZEBs are supposed to grow widespread in 2020.
State-of-the-art technology from Shimizu for reducing CO2 emissions