By linking the current economical activities and the environmental load, concepts such as "factor 10" and "factor 4" were submitted by various organizations regarding the measures to be taken by the society in order to realize a sustainable society. The common suggestion of these ideas is the necessity for reduction of environmental load per unit economical activity by improving the efficiency of the use of resources and energies as much as possible. This concept can be expressed as "eco-efficiency." Adopting the idea of eco-efficiency, this document examines particularly what roles the technology has played and how Japan's eco-efficiency has changed.

### 2. Improvement of eco-efficiency and progress of environmental technology

Japan has almost completely overcome serious problems created during the rapid growth period. The primary factors of this background are establishment and implementation of various regulations and the introduction of pollution control facilities by many enterprises. Constant improvement of the performance control facilities and progress in the development of engines for reduction of automobile exhaust are also to be noted. After the oil crisis, Japan has rapidly improved the energy efficiency of production facilities, transportation facilities, and electrical appliances.

Steady reduction of environment load, that is improvement of eco-efficiency, can be traced in the process of economical growth, with background development of various environmental technologies such as pollution reduction technology and energy conservation technology. It is possible to discover that, in many cases, introduction of new regulations and promotion measures in terms of policies are extremely effective.

For instance, the strict exhaust gas regulation that was introduced in Japan for the first time in 1978 was one factor of the onslaught of the Japanese automobile industry on the world market. Active development of low pollution vehicles brought Japan into a superior position in the world's low pollution vehicle market, and the active development promotion policy for solar power generation.

Transition of solar battery conversion efficiency in the New Sunshine plan (cell based)

Note: CdTe: Cadmium tellurium

Source: Presentation submitted by the Comprehensive Resource Energy Research Association, New Energy Section

Result and outlook of introduction of residential solar power generation

Source: New Energy Foundation

operation resulted in rapid improvement of power generation efficiency and rapid propagation into general households. In order to realize and propagate fuel cell batteries, and to lead the world in this regard, Japan is constantly progressing with the promotion of technology development and active introduction of fuel cell batteries in public organizations including Governments.

Plan for introduction of low-emission vehicles as general public vehicles of Japan

Year	Up to 2000	Up to 2001	Up to 2002	Up to 2003	Up to 2004	Total
Number of vehicles introduced	316	1,013	1,860	1,931	1,901	7,021
Electric-powered vehicles	8	0	0	0	0	8
Natural gas vehicles	57	26	59	58	52	252
Methanol vehicles	0	0	0	0	0	0
Hybrid vehicles	251	689	1,039	1,101	1,100	4,180
High fuel efficiency/superior emissions vehicles	0	298	762	772	749	2,581

Number of ownerships	316	1,329	3,189	5,120	7,021
Introduction rate %	4	19	45	73	100

Includes the Parliament and Courts in addition to Agencies and Ministries. The number of vehicles in 2001 is an expected value and may be changed. In this case also, the installation is 100%.

Presentation: Ministry of the Environment

Conversion processes and efficiencies of various power generation methods

Power generation method	Conversion process	Efficiency %
Fuel cell battery	Chemical→electricity	40~60
Steam gas turbine power generation	Heat→ machine→electricity	30~42
Diesel power generation	Heat→ machine→electricity	25~35
Thermoelectric converter	Heat→electricity	8~15
Thermal converter	Heat→electricity	6~10
Solar battery	Light→electricity	10~20

Note: The efficiency indicates the percentage of electric energy converted from the energy source that is indicated on the left-hand side of the conversion process.

Source: Prepared by the Ministry of the Environment based on "Story of Battery" by Hironosuke Ikewa and "Resource Energy Yearbook" by the Data Examination Association of the Ministry of International Trade and Industry