Carbon Footprint Assessment of Water Supply Systems in Taiwan

Abstract

Recent studies indicate that global warming is worsening, tremendously affecting our environment.Hence, reducing CO2 emissions is one of the most pressing issues in environmental protection. Among the natural resources, water is one of the most vital. Having a clean and secure water supply, as well as a water distribution system, is crucial for modern society. From a life cycle perspective, a complete water supply system is complicated and contains substantial, embedded carbons, which comprise infrastructure, as well as purification facilities and related processes. Assessing the total carbon footprints of a complete water supply system would present numerous benefits. Such evaluation covers the examination of water supply efficiency and identifying opportunities for carbon emission reduction after a thorough inventory.In addition, calculating the carbon footprints of products has become increasingly important for global enterprises. Determining the carbon footprint of unit of water (i.e., in kgCO₂ e/m³) is necessary for the calculation of a product’s carbon footprint.

In view of the above-mentioned issues, several countries, including Scotland, the UK, USA, Japan, and Italy, have studied the carbon footprints of water supply systems. In Taiwan, previous studies conducted to determine the carbon footprints of water supply systems were not based on a life cycle perspective.Commissioned by the Water Resources Agency of the Ministry of Economic Affairs, this study calculated the carbon footprints of five water supply systems, each with different characteristics in terms of topography, scale, raw water quality, and purification process. The water supply systems studied included a traditional purification plant, a purification plant with high-turbidity raw water, a multi-process purification plant, an advanced purification plant, and a desalinization plant. The scope of inventory and assessment includes the intake, the purification, and the distribution stages, as well as the infrastructure and the chemicals used that are associated with these stages. Carbon footprints are calculated based on the unit water sold (m³). The calculation is performed in accordance with the standards set by the Taiwan Carbon Footprint Calculation Guidance for Products and Services. Preliminary results show that the carbon footprints of the traditional purification plant, the purification plant with high-turbidity raw water, the desalination plant, the advanced purification plant, and multi-process purification plant are 0.1768, 0.2646, 9.6249, 0.4969, and 0.1942 kg CO2e/m³, respectively.