Modeling and assessing the integration of CO2 capture in waste-to-energy plants delivering district heating

The waste-to-energy (WtE) sector is assuming an increasingly important role in net-zero pathways owing to its hard-to-abate emissions and its inherent potential for generating negative emissions. Thus, exploring effective strategies for CO2 capture and storage (CCS) integration with WtE plants that address the challenge posed by their coupling to district heating (DH) networks and the need to deliver both heat and electricity to customers is essential. This study presents a mass and energy balance model of a WtE plant with post-combustion CO2 capture process to assess the integrated system’s energetic feasibility. Results show that despite the extensive DH demand in heat-based WtE plants, enough excess heat is available to capture around 60% of the CO2 generated. As such, negative emissions can be achieved without external heat requirement at an efficiency reduction of 16%. By incorporating heat pumps and utilizing CCS waste heat for district heating, CO2 capture can be maximized at a total efficiency reduction as low as 36%. This is comparable to CCS in power-based WtE plants with no district heating. These findings highlight potential efficiency gains through the synergistic integration of CO2 capture and district heating, providing additional opportunities for WtE plants to contribute to the net-zero transition.