Performance Evaluation of Waste Heat Integration from Electrolyzers Between District Heating Condensers in Combined Heat and Power Plants

As Sweden advances toward large-scale hydrogen production for industrial applications, low-grade waste heat (≈80 °C) from electrolyzers becomes available. A proposed solution is to integrate this heat between the two condensers in a combined heat and power plant. This can be done with different configurations, which were setup and studied. At full load, introducing 15 MW of heat increased electrical power output and cycle efficiency by up to 169 kW and 0.173% points, respectively. The same configuration under part-load showed the best improvement up to 11 MW of added heat, providing up to 302 kW in power output compared to the reference part-load case without waste heat. At a further increase in heat input at part-load, the best configuration shifted. At 15 MW of heat input, the best case resulted in a 393 kW reduction in electric output relative to the reference case. This is still significantly better than using a heat pump, which would require up to 1.43 MW for the same heat utilization. The results show that direct integration of electrolyzer waste heat into CHP plants can enhance electrical efficiency and power output without increasing electricity consumption, offering a viable and relatively simple alternative to heat pump-based solutions in district heating systems.