## (3) Status of the commercial and residential, and transport sectors

In contrast to the industrial sector, $ CO_{2} $ emissions caused by the commercial and residential, and transport sectors have increased substantially from the base year 1990 (44.6% increase for commercial and other sector, etc., 36.7% increase for residential and 18.1% increase for the transport sector). Also, those three sectors collectively account for as much as 57% of all $ CO_{2} $ emissions in 2005. At the same time, however, it can be translated into a large reduction potential expected from those sectors, and this potential could be realized by way of an adoption of emission reduction measures by a large number of representatives from these three sectors. Thus, it is important to understand how technologies could specifically contribute to $ CO_{2} $ emission reduction in those sectors in particular, and the following subsections will explain the details of such potential, while focusing on those technologies at the stage of practical utilization.

### 2. Statuses of Practical Application of Various Technologies to Products and Systems

Technologies could contribute to $ CO_{2} $ emission reduction only after they are successfully applied to products or systems, commercialized and widely utilized.

Here are examples of such applications that have a large potential of wide utilization. Those can be roughly divided into technologies for energy users and technologies for energy suppliers.

## (1) Energy saving technologies for energy users

Figure 3-4-3 and Figure 3-4-4 show the $ CO_{2} $ emission structure in the commercial and residential sectors, including households,

offices and business facilities. Those figures show that water heaters, air conditioners and power unit (refrigerators, lighting equipment, etc.) collectively occupy a large proportion of the $ CO_{2} $ emissions. Also, about 90% of the total $ CO_{2} $ emissions generated by the transport sector are attributed to the use of motor vehicles, and about 50% originate from private passenger cars, as shown by Figure 3-4-5.

Since the $ CO_{2} $ emissions attributed to the said equipment and machines are large, reduction of them would produce substantial effects, and it is therefore important to work aggressively on those equipment and machines. The following subsections will explain the potential of $ CO_{2} $ emission reduction expected mainly from the said equipment and machines through the promotion of technology utilization.

Figure 3-4-3: Structure of $ CO_{2} $ emissions in residential sector (FY2005)

Figure 3-4-4: Structure of $ CO_{2} $ emissions in commercial and other sector (FY2005)

Source: Compiled by the Ministry of the Environment based on the Institute of Energy Economics, Japan, Handbook of Energy & Economic Statistics in Japan

Source: Compiled by the Ministry of the Environment based on the Institute of Energy Economics, Japan, Handbook of Energy & Economic Statistics in Japan

Figure 3-4-5: Structure of $ CO_{2} $ emissions from the transport sector (FY2005)

Source: Compiled by the Ministry of the Environment based on Greenhouse Gas Inventory Office of Japan, of the National Institute for Environmental Studies, National GHGs Inventory Report of Japan