Recently, increasing urban temperatures due to the Urban Heat Island (UHI) effect and Global Warming (GW) have been remarkable in some Japanese metropolises. The UHI effect and GW not only cause temperatures to rise, they also have other diverse impacts on urban dwellers. Therefore, it is important to understand the effect of temperature increase on urban dwellers to take action for preventing the occurrence of adverse impact. In this regard, the authors have shown the overall perspective of the effect of temperature change on urban dwellers by relation diagram, and evaluated the influence on energy, resources, health, air pollution etc. as much as possible quantitatively.
This paper aims to comprehensively and quantitatively evaluate the impact of urban outdoor temperature change on energy consumption in Osaka Prefecture, based on the data by authors and Japanese government, energy supply company and so on. In this paper, annual evaluations concerning electric power and city gas, oils, vehicle fuel were conducted. The evaluation time was set 2000 as the past, 2015 as the present, 2040 as the future.
The results of this research are described below.
1) Regarding the temperature sensitivity of each energy source, the electric power showed a V-shaped tendency for all building use. City gas for residential showed a year-round sensitivity that drew a loop. Business and commercial showed V-shaped, but very weak in both summer and winter. Residential oil was sensitive only in winter. Business and commercial oils and vehicle fuel were negligible.
2) Regarding the temperature effect of energy consumption in 2015, the total amount of electric power changes was positive, with the change in summer exceeding winter. Since the city gas changed greatly for residential, the total showed a large negative value. The oils showed a negative in all uses, with the residential being dominant. The vehicle fuel was positive for both gasoline and diesel, with gasoline being dominant.
3) Regarding the overall evaluation in 2015, the total changes in all energy resources were almost zero. In other words, the overall energy consumption hardly changed when the outside air temperature rose 1 °C uniformly in Osaka in 2015.
4) Regarding the future changes of the influential factors, outside temperature in Osaka was predicted to rise by 1.1 °C for annual average from 2015 to 2040.
5) Regarding the effect of temperature on energy consumption in 2040, the amount of electric power change in summer greatly exceeded winter, and the total showed positive. City gas became negative due to the dominant of residential use. Oils had a negative change in all use, and residential use were particularly dominant. Regarding the total evaluation in 2040, the total change of each energy resources showed positive value.
6) Concerning the secular change, the impact of outdoor air temperature change (°C) on the total change of all energy consumption was 2.2 PJ in 2000, 0.0 PJ in 2015, 3.9 PJ in 2040, and there was no constant rising trend from the past to the future. From 2000 to 2015, the overall change was offset by an increase in negative changes in city gas. On the other hand, from 2015 to 2040, the overall change increased due to temperature rise.