Carbon emissions of water supply systems in China: Characteristic, right, right balance and reduction potential assessment

Abstract

In light of the global consensus on low-carbon development and the imperative to reduce greenhouse gas emissions, coupled with China's strategic objective of achieving “carbon neutrality” and reaching its carbon peak, it becomes increasingly essential to focus on areas that necessitate adaptation for low-carbon development. One such critical area is the water supply system, known for its substantial contribution to carbon emissions. To assess the situation, this study constructed an evaluation framework for carbon emissions of water supply system, which comprised of emission characteristic investigation, emission right allocation and right balance assessment. For emission characteristic investigation, data on water supply quantity, pipe network pressure, and energy consumption was utilized to calculate carbon emissions produced by China's water supply system and investigated the spatial and temporal distribution of emissions. The analysis revealed a minor increase in carbon emissions from 2010 to 2018, with a significant turning point occurring in 2016. Specifically, carbon emissions in 2018 ranged between 1.03 × 107 kgCO2 and 3.15 × 109 kgCO2. Coastal areas, such as Guangdong and Jiangsu, exhibited a higher level of carbon emissions. This study constructed a provincial allocation model of carbon emission rights, utilizing the shadow price model and entropy method while adhering to the principle of fairness and efficiency. By comparing the value of emission right and emission amount, the provincial balance of carbon emission right in 2018 was evaluated. It was discovered that 14 regions demonstrated varying levels of carbon allowance surpluses. Conversely, 12 regions exhibited insufficient spatial balance, which were subsequently classified as exhibiting mild, moderate, or severe deficiency. Additionally, emission reduction pressures among these regions were assessed through the analysis of the ratio between theoretical emission right and actual amount, as well as levels of economic development. The carbon emission reduction potential scores of different regions were calculated using principal component analysis based on five dimensions, namely policy driver, engineering test and research level, level of economic development, forestry carbon sink and emission reduction efficiency. Our findings indicated that the degree of insufficient balance between emission reduction potential and carbon emission allowance showed a certain convergence. Ultimately, we proposed tailored emission reduction paths for water supply systems in each region, which may serve as theoretical and technical references towards achieving the “double carbon goals”.