Yoichi Kaya

Two model analyses of the urban structure of minimal transportation energy consumption

The transportation sector needs to reduce fuel consumption to deal with global warming because it depends on fossil fuels strongly and it seems to be difficult to substitute other fuels. This study aims at investigating an optimal land use in urban areas from the viewpoint of reducing energy consumption for transportation. For this purpose, the authors developed two kinds of models. One minimizes the total trip length under the condition of constant congestion. The other minimizes the fuel consumption directly where congestion is taken into account endogenously. The optimal structures calculated numerically illustrate that business areas are located around the center of a city while residential areas are on the suburbs, which is similar to the actual land use observed generally. These results are compared with the land use of the central business district (CBD) in Tokyo.

Japanese strategy for mitigating global warming

Abstract This paper illustrates first what the government of Japan intends to do with a few official pledges on mitigating global warming, such as the action plan and the famous idea of New Earth 21 program, toward long term stabilization of CO2 concentration in the air. In practice, however, there are a number of factors which may disturb realization of the targets envisaged in these plans. Limitation to advancement of further energy conservation, not only in industrial sectors but also in other sectors where individual consumers play key roles, is certainly serious. Another crucial factor is the nuclear power. Recent accident at the experimental FBR, Monju, has influenced the public acceptance of nuclear power very seriously, and the government is now at the stage of re-designing the future scenario of nuclear power, taking into account both the opinions in favor of nuclear and those of anti-nuclear. Nevertheless most of energy experts believe that nuclear power is safe and also economical enough to be maintained for the intermediate future at least in Japan so that strong policy measures are to be introduced to improve public acceptance of nuclear power. The second part of this paper describes the future of so called “new energy” which the government of Japan is eager to develop and also the limits to development of these “new energy”. The third part is contributed to description of R&D of long term technological options and also difficulties in realizing these options. It is also worth noting that Japan, both government and industries, has much interest in CO2 removal from flue gas of power plants and its disposal.

Japan's strategy in technology development for mitigating global warming

Abstract Japan is a country much concerned with global environmental issues. This paper describes Japans prospect on energy and CO 2 emission, together with prospects of other developed countries. Then the needs for developing long term innovative technologies are demonstrated with a few examples of technologies being developed under MITI R&D program.

Optimal Urban Land Use to Reduce Energy Consumption in Transportation, Commercial and Residential Sectors

Abstract This study investigates land use in urban areas from the viewpoint of energy conservation to reduce CO2 emission. Normative model is developed which minimizes total primary energy consumption in a modeled city. Numerical results describe it is optimal that business areas are allocated around the center of the city and residential areas are in the suburbs. Sensitivity analyses show that there exists the optimal position of co-generation plants, which means that land use allocation and plant allocation should be considered at the same time to make consistent plan for energy conservation in city-wide level