Photographer: SS.Inc Toshifumi Kato
The figure illustrates the process of reducing CO2 emissions generated by the consumption of electricity, gas, oil (non-electricity sources), among others, with the ultimate goal of achieving zero emissions.
Energy consumption is minimized through energy conservation, and emissions per unit of production are reduced by promoting electrification and the use of renewable energy, hydrogen gas, new types of gas, and other energy sources.
Then, capturing and storing CO2 will help achieve net-zero emissions.
The government is promoting GX (Green Transformation) to achieve this process, shifting from fossil fuels that generate greenhouse gases, such as CO2, to clean energy sources, such as solar and wind power, and transforming the entire economic and social system.
GX is implemented across all industries, and the six main priorities related to construction and energy are as follows:
◼Transition from natural gas to hydrogen gas and ammonia gas
◼Decarbonization of steel and cement manufacturing processes
◼Promotion of ZEB and ZEH and popularization of wooden buildings
◼Digital investment and carbon neutralization of data centers
◼Development and popularization of storage batteries to promote and stabilize renewable energy
◼Demand Response (DR)
At Kume Sekkei, we have been advocating for the realization of ZEB to promote GX.
While achieving ZEB in calculations is a given, we place greater emphasis on achieving ZEB in actual operation. Our ZEB chart indicates the energy consumption ratio (BEI) based on actual operational results.
The national CO2 emissions reduction target is 46% by fiscal 2030, 60% by 2035, and 73% by 2040, compared to 2013 levels.
The Act on the Rational Use of Energy, enacted in 2017, was strengthened in 2024, and will be further upgraded by 2030, with a BEI of 0.6 to 0.7, i.e., ZEB Oriented, becoming the minimum standard.
On the other hand, buildings currently being designed in 2025 will begin operation by 2030 at the latest and will continue to operate and emit CO2 thereafter.
Efforts to reduce BEI should start as soon as possible. Kume Sekkei will propose to clients to achieve at least ZEB Oriented standards in the buildings currently being designed, promote the realization of Nearly ZEB and net ZEB, and contribute to achieving national targets.
Water resource conservation must be considered equally important as energy consumption and the reduction of CO2 emissions.
The balance between supply and demand for agricultural water and domestic water, both of which are essential to our lives, has begun to falter.
Also, energy is required to obtain clean tap water.
Water used in buildings includes drinking water, water for flushing toilets, and water for watering plants.
In particular, it is important to minimize the use of tap water for toilet flushing, which consumes a large amout of water.
To achieve this, it is important to promote the use of rainwater harvesting systems and wastewater recycling systems.
While there is a ZEB target for energy consumption, there is also a ZWB (Zero Water Building) target for water consumption.
Achieving ZWB is another urgent challenge for us in the construction industry, along with ZEB.
ZWB is a concept that offsets the "total water consumption or total potable water (municipal water) consumption" in a building with the sum of "substitute water" and "reclaimed water."
There are no ZWB standards in Japan, so the ZWB evaluation criteria used in the United States are provided below.
Under all criteria, it is necessary to achieve ZWB by adopting water-saving devices and other measures, (1) to reduce the total water consumption or total potable water consumption that includes water supply consumption, and (2) to use recycled wastewater, rainwater, and reclaimed water as "substitute water" to cover part of the water consumption specified in (1).
The reduction of water consumption described in (1) and (2) is important as a measure for water resource conservation, as mentioned above.
Furthermore, we emphasize the importance of returning rainwater to the ground by adding "(3) the amount of returned water" as an evaluation item.
Returning rainwater to the ground helps prevent river flooding, replenishes groundwater, and reduces the burden on sewage systems.
Kume Sekkei's various efforts are not limited to promoting ZEB, but also include significant reductions in CO2 emissions in medical facilities, such as the Obihiro-Kosei General Hospital, which received the highest global rating from ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), and the Aichi Prefectural Environmental Research Center and Aichi Prefectural Institute of Public Health, which achieved net ZEB through commissioning (performance verification) and received high praise from ASHRAE.
We are also undertaking many initiatives to realize ZWB at Kawasaki City Hall and Toranomon Hills Station Tower.
From now on, Kume Sekkei will continue our efforts to create environmentally friendly buildings with excellent environmental performance, aiming to achieve global carbon neutrality by 2050.
