For his presentation, “From Coal to Green Iron: Repurposing Combined Heat-and-Power Plants to Run on Carbon-Free Iron,” Jannik Neumann, a doctoral candidate at the Institute of Technical Thermodynamics, was honored with the Best Presentation Award at the 2nd ISESA in Stuttgart. The work presents a clear technical pathway for retrofitting existing coal power plants (especially combined heat and power plants) to use iron as a carbon-free energy carrier.

A large and young fleet of coal power plants exists worldwide. To meet climate goals, premature shutdowns are necessary, which leads to a loss of assets (stranded assets). At the same time, combined heat and power (CHP) systems are often available as established infrastructure and increase fuel utilization efficiency. Retrofitting these plants to use green iron as fuel maximizes the reuse of existing facilities, thereby minimizing stranded assets. Iron power plants with CHP provide dispatchable, CO₂-free heat and electricity.

By determining the operational maps of a reference coal CHP plant and the retrofitted iron CHP plant, the analysis shows that the overall efficiency can increase by up to 6 percentage points. The reasons for this include lower auxiliary power consumption (e.g., no flue gas treatment) and lower exhaust gas temperatures, resulting in higher boiler efficiencies.

The results were developed in collaboration with the Institute for Simulation of Reactive Thermo-Fluid Systems STFS as part of the : Metal Energy Hubproject