ABSTRACT
District energy systems, or district heating and cooling systems, aim to use as much local energy as possible, including waste heat, natural energy sources as free cooling and renewable energy, to increase the total energy efficiency at a district or city level. District energy systems, defined as public service, are considered as part of the cities’' sustainable development action plans and contribute to the United Nation's (UN'’s) Sustainable Development Goals (SDGs) through saving energy consumption, and reducing greenhouse gas emission and air pollution. However, due to the integration of various energy supply resources, like waste heat, access heat and free cooling from various natural sources, and multiple benefits brought by district energy systems, it is necessary to develop a system of multiple indicators to evaluate their contributions to sustainability through dimensions of energy efficiency, energy security, environment and economy. This chapter analyses the sustainability indicators for district energy systems to assist the procedure of decision making at city level for sustainable development. These indicators were utilised in demonstration district energy projects of pilot cities in India and Malaysia to showcase how to select suitable energy systems and their benefits compared to traditional heating and/or cooling systems.
