Grey relation analysis of carbon dioxide emissions from industrial production and energy uses in Taiwan

This study aims to identify key factors affecting energy-induced CO₂emission changes from 34 industries in Taiwan, in order to have an integrated understanding of the industrial environmental-economic-energy performance and to provide insights for relevant policy making in Taiwan. Grey relation analysis was used in this paper to analyse how energy-induced CO₂emissions from 34 industries in Taiwan are affected by the factors: production, total energy consumption, coal, oil, gas and electricity uses. The methodology was modified by taking account of the evolutionary direction among relevant factors. Furthermore, tests of sensitivity and stability, which are seldom discussed in most grey relation analyses, were conducted to ensure the reliability of outcomes. We found that values ranging from 0·3 to 0·5 are appropriate, and the analytical results with value of 0·5 offer moderate distinguishing effects and good stability. Results indicate that industrial production has the closest relationship with aggregate CO₂emission changes; electricity consumption the second in importance. It reveals that the economy in Taiwan relied heavily on CO₂intensive industries, and that electricity consumption had become more important for economic growth. The relational order of fuels is electricity, coal, oil then gas, accordant with their CO₂emission coefficients in Taiwan. The positive relational grade of aggregate production implies that the aggregate industrial CO₂intensity tended to decline. The total energy consumption had a smaller and negative relational grade with CO₂emissions, and implies an improvement on aggregate energy intensity, while the CO₂emission coefficient increased. For industries with significant influence on CO₂emissions, the total energy consumption had the largest relational grades. It is important to reduce the energy intensity of these industries. Nevertheless, it is also critical to decouple energy consumption and production to reduce the impacts of CO₂mitigation on economic growth.