ZEB (Zero Energy Building)
This refers to a building that has annual energy consumption that is effectively zero.
As global warming progresses, the proliferation of zero energy buildings that are ultra-eco-friendly will be key to achieving a sustainable society.
Shimizu is continuing to take on the challenge of creating zero energy buildings through concerted efforts in energy conservation, and creation of new energy alternatives and energy storage.

The High Goals Set at COP21

At the 21^st Conference of Parties on the U.N. Framework on Climate Change (UNFCC, “the Paris Climate Conference”) in 2015, the Paris Accord was adopted, establishing the legal framework for 2020 and beyond. Japan submitted a goal of achieving a 26% reduction in greenhouse gas emissions compared to the 2013 level by 2030. As a subsidiary goal to that, the government set the goal of reducing greenhouse gas emissions in the businesses and other segment and the household segment related to energy consumption in buildings and homes by 40% compared to 2013 levels by 2030.
This extremely high goal cannot be achieved without the promotion and proliferation of ZEB.

Ahead of the Construction Industry in Achieving ZEB

Shimizu, which was the first in the construction industry to take on the challenge of ZEB, achieved a 43% reduction in greenhouse gas emissions in the main building of the Shimizu Institute of Technology which was completed in 2003, compared to the 1990 level.
The company’s head office, which was completed in 2012, is an ultra-eco-friendly urban office building equipped with solar panels and other energy generation technology, in addition to a radiant air conditioning system^*1 and many other types of energy-conserving technology. Our head office was certified as the first large carbon neutral^*2 building in Japan. This was achieved by using CDM (Clean Development Mechanism) greenhouse gas emission credits acquired overseas.
Shimizu subsequently succeeded in designing and building the first zero energy building (ZEB) in Japan. It was the Seicho-no-Ie's Office in the Forest, which was completed in 2013.

Seicho-no-Ie's Office in the Forest, Japan’s First ZEB

The Seicho-no-Ie's Office in the Forest is located in the city of Hokuto, in Yamanashi Prefecture, a location with an abundance of wood-based biomass resources and where the average annual amount of sunlight is 2,100 hours, high compared to the national average.
To take advantage of the unique characteristics of this area, solar panels were installed on the entire roof, and these solar panels supply approximately 60% of the annual electricity consumption. Local resources are also used to generate energy by using a wood chip gasification cogeneration system and a wood pellet boiler, among other systems.

Maximum Use of Natural Energy

Using a detached pavilion-style skip-floor architecture that made advantageous use of the high and low elevations on the grounds maximized the natural air flow and made the use of air conditioning unnecessary. The use of natural light has also made the use of artificial lighting almost unnecessary on sunny days. Shimizu also worked to conserve energy by using a solar heat collection system to supply more than 60% of the heating energy. This was achieved by making sure the buildings were well heat-insulated and combining the solar heat collection system with a pebble heat storage system beneath the floors.

Optimal Electrical Power Control via a Microgrid

A microgrid system was constructed using both solar panels and a biomass gasification cogeneration system for power generation. The system stores the energy generated in a high-capacity lithium-ion battery, which is then discharged to provide stable electricity supply. This saves power by forecasting and regulating electricity use without waste, based on meteorological data and data on the status of facility operation.