Water-energy-carbon nexus assessment of China’s iron and steel industry: Case study from plant level

Abstract

Steel production is not only a primary contributor to energy consumption and carbon emissions but also a major source of water consumption in China. The perspective of a water-energy nexus to reduce environmental pressure on steel production has become a hot topic. In this study, a plant-level nexus approach was used to assess the relationship between energy and water consumption, and CO2 emission of a typical Chinese steel company. Integrated material and energy flow and water footprint models were developed to assess the nexus. Economy, energy-saving, water-saving, and carbon-reduction potential, of 31 energy-saving technologies (ESTs) were evaluated by the water-CO2 energy conservation supply curve model. The modeling results showed that 590.16 kgce of fuel and power and 3.17 m³ of industrial fresh water are required to produce one t of crude steel by the case company, while generating 2437.45 kg of CO2 emission and a water footprint of 9.48 m³. The costeffectiveness of 31 ESTs was evaluated in different scenarios. The selected 31 ESTs contribute 7.84 GJ/t of energy savings, 1.65 m³/t of direct water savings, 7.54 m³/t of indirect water savings, and 911.26 kg/t of CO2 emission reduction. When considering the water savings and carbon reduction benefits of the selected technologies, the energy conservation cost reduced from CNY 1924.76 per GJ to CNY 1658.37 per GJ. This study highlights the need for policy development and production planning through the perspective of a water-energy-carbon nexus.