Transition scenario of Nakanoshima business/cultural area: A model of low-carbon district in warm climate

Panel: 5. Saving energy in buildings: The time to act is now

This is a peer-reviewed paper.

Authors:
Yohei Yamaguchi, Osaka University, Japan
Yoshiyuki Shimoda, Professor, Graduate School of Engineering, Osaka University, Japan
Takehito Kitano, The Kansai Electric Power Co., Inc.

Abstract

Authors propose long-term scenarios until 2050 for Nakanoshima Area, a central business/cultural area in Osaka, Japan, consisting of 1.2 million square meters of commercial buildings. Proposed scenarios include:

- long-term forecast of available technologies and those efficiency,

- implementation of available technologies at renovation and new-construction of buildings,

- expansion of existing community energy systems using river water as heat sink,

- fuel switching from city gas to electricity in cooling, heating and water heating, with the use of heat pumps, and

- improvement in CO2 emission coefficient of electricity.

This study shows a possible pathway to realize a large CO2 emission reduction in cities in Temperate and Tropical zones where energy consumption for heating is not dominant. Since heating energy is dominant in Europe, the combination of building insulation and CHP is a promising strategy for CO2 reduction. However, it does not result in a sufficient reduction in the warm climate. Thus, every available technology must be fully implemented to reduce a large amount of CO2 emission, which is examined in this study.

In this paper, authors present the result of survey on the actual energy consumption of the buildings in the area. Then a bottom-up simulation analysis to understand the structure of energy consumption and to estimate CO2 emission until 2050 is presented. Our preliminary analysis showed that the Area emitted 92 thousand ton of CO2 in 2008. The emission is equivalent to 0.5% of the total emission of Osaka city. Approximately 30% of the current emission can be reduced until 2030. Further analysis will be done. Authors finally discuss the following three points:

- Feasibility of a large CO2 reduction and individual and aggregated contribution of available technologies;

- Opportunity, challenge and contribution of early decision;

- Implications learned from this study to reduce CO2 emission of the commercial sector in Japan and other areas.