Water-energy and GHG nexus assessment of alternative heat recovery options in industry: A case study on electric steelmaking in Europe

In the last few years, the water-energy nexus concept has emerged as a global issue. However, studies on European countries are relatively few, and often focused on agriculture. Cooling purposes represent the main part of industrial water demand, and waste-heat recovery is a main strategy to improve resource efficiency. This paper presents a real case study of low-temperature waste-heat recovery in an electric steelmaking industry and evaluates the impact of feasible interventions on primary energy and water consumption, as well as on CO2 equivalent emissions. Based on a Europe wide review of energy and water prices, of energy sources and corresponding resource efficiency indicators, a Monte Carlo model was developed to undertake a generalization of the case study to the EU-15. It was found that solutions with the lowest primary energy demand and the lowest CO2 equivalent emissions demonstrate the greatest water footprint. This is the case of some southern European countries, where heat recovery projects with the highest water intensity are feasible due to high electricity and low water prices. As increasing carbon prices may exacerbate this phenomenon, inducing a switch to water intensive technologies, incentives to carbon emission reduction should be carefully designed.