Techno-economic and carbon footprint assessment of advanced waste-to-energy with CO2 capture and storage for East Coast cluster (Flexible Funding 2023)

Professor Dawid Hanak, Teesside University, was awarded funding in the UKCCSRC’s Flexible Funding 2023 call to look at “Techno-economic and carbon footprint assessment of advanced waste-to-energy with CO2 capture and storage for East Coast cluster”.

Waste-to-Energy (WtE) plants play a critical role in managing municipal solid waste while simultaneously generating energy. Incinerating waste that would otherwise end up in landfills, WtEs contribute to reducing methane emissions from decomposing organic waste and offsetting the need for fossil fuels. However, despite their environmental benefits, WtE plants remain significant contributors to CO₂ emissions.

WtE facilities generate emissions from the combustion of waste materials, which contain both fossil-based (plastic, synthetic materials) and biogenic components. To achieve net zero, such as those laid out in the Paris Agreement, the role of WtE plants must be re-evaluated. The preliminary work on WtE and CCS integration by the Energy Systems Catapult [1] showed that the specific CO₂ emissions from WtE are 600 gCO₂/kWh. Following the footsteps of the unabated coal-fired power plants, unabated WtEs are forecasted to be phased out by 2040, indicating the need to develop low-carbon alternatives. This is particularly critical in the UK industrial clusters, such as Teesside Cluster, where WtEs are forecasted to account for around 18% of the total CO₂ emissions. This represents a significant barrier to achieving net-zero goals unless advanced carbon capture technologies are implemented.

Despite high energy and economic penalties, advanced amine scrubbing is now considered the technology of choice for industrial decarbonisation due to its high maturity. Yet, this technology may not be viable for decarbonising the WtE plants. The study by AECOM [2] indicated that the amine-based capture unit could require up to 66% of the total thermal input to the steam turbine at the combustion-based WtE plant. A study by Magnanelli et al. [3] demonstrated that the integration of amine scrubbing could result in up to a 30% reduction in power output and a 12% reduction in the heat output from a typical combustion-based WtE plant. Supplying such an amount of steam will not only be limited by technical considerations but will also substantially impair the economic viability of the WtE plant.

Figure 1: Schematic of calcium looping combustion

In this project, we have performed a comprehensive techno-economic feasibility and carbon footprint assessment for emerging CO₂ capture technologies based on the carbonate looping process. We have considered WtE plant configurations:

• the Cleveland WtE plant (a reference host plant)
• the Cleveland WtE plant retrofitted with post-combustion calcium looping (CaL); and
• the novel WtE plant based on calcium looping combustion (CaLC-WtE; Figure 1).

Our study showed that retrofitting CaL to the Cleveland WtE plant would result in the net efficiency penalty of about 5% and break even cost of electricity of 136.3 £/MWh. Such a performance was competitive to that of the unabated WtE plant that was shown to result in the break even cost of electricity of 132.9 £/MWh. We associate this to a substantial increase in the waste processing capacity of CaL (+85%) and opportunity to provide CO₂ offset services (-1284.3 gCO₂/kWh). The novel CaLC-WtE resulted in a lower net efficiency penalty of 4.3% mostly due to no requirement for energy-intensive air separation unit. The proposed process resulted in the lowest break even cost of electricity at 96.8 £/MWh. We associate this solely to the opportunity to provide CO₂ offset services at -721.1 gCO₂/kWh.

In addition to delivering on the main objective of this project, the NZIIC team have actively engaged with academic and non-academic community within the East Coast Cluster and beyond. Our webinar attracted over 270 unique views and led to discussions with CSG and Suez in the East Coast Cluster. It also led to invitations to present our work through a series of events, including those organised by IMechE and FERF. The project also resulted in two articles for professional and general audience, published by Illuminem and Transition to Net Zero edited by Prof. Hanak. Follow up academic publications and webinars are in development by the NZIIC team.

Overall, we are grateful for the support provided by the UKCCSRC. It enabled us to test our hypothesis and generate underlying data to support further development of carbonate looping technology. We are currently in the process of developing a follow-up application that will debottleneck the technical components of this technology.

Read more about this project here and connect with Prof. Hanak on LinkedIn.

References

1. Gammer D, Elks S. Energy from Waste Plants with Carbon Capture. Energy Systems Catapult; 2020.
2. AECOM. Next Generation Carbon Capture Technology. 2022.
3. Magnanelli E, Mosby J, Becidan M. Scenarios for carbon capture integration in a waste-to-energy plant. Energy 2021;227:120407.