Evaluating Waste Heat Recovery Potentials and Key Performance Indicators in Energy-Intensive Sectors

Energy efficiency and climate protection have shaped environmental discussion. Climate change objectives and regulations are increasing, especially in heat- and energy-intensive industries. An example is the iron and steel industry, which accounts for approximately 4–5% of global energy consumption and CO2 emissions. This study reviews waste heat recovery potentials and elucidates methodologies for their quantification based on physical and technical optima while ensuring economic production conditions (cost minimization, maximization of plant utilization, preservation of product quality, and competitiveness). It further introduces and explains the KPIs as specific heat input (kWh/t) and heat utilization rate (%), describing the economic potential of waste heat, overall prices, and the cost structure of alternative production technologies or heat sources. These KPIs are critical for evaluating waste heat utilization efforts and detailing their calculation processes. Ways of waste heat recovery are linked to an overview of possible technologies.