Guest Post : Waste-to-energy integrated with carbon capture: Combating Climate Change for Non-Recyclable Waste

The world is currently emitting ca. 60 gigatons of CO2 equivalent GHG emissions. The current carbon budget is estimated to be 500 and 1200 Gt CO2 equivalent GHG emissions for the 1.5°C and 2°C limit, respectively. Meaning the 1.5°C limit will be reached in less than one decade and the 2°C limit within two decades. This urgency underscores the need for immediate action in both reducing and removing CO2 emissions. While emission reduction remains paramount, achieving net-zero targets will also necessitate significant carbon removal efforts. Every sector, including waste management, must innovate to minimize climate change.

Looking at Waste to Energy (WtE) as a standalone solution it is a carbon reduction technology. When combined with carbon capture and storage it becomes a carbon removal technology. WtE’s carbon reduction and removal potential is huge and will be further explored in this article.

Moving waste up in the waste hierarchy is the most effective way to address the waste management sector’s GHG emissions.

By 2050, the global production of municipal solid waste (MSW) is projected to increase by 80%, reaching 3.8 billion tonnes annually. This rising volume underscores the necessity for implementing a sustainable waste management framework. Central to this framework is the waste hierarchy, which ranks and prioritizes different waste treatment options.

The waste hierarchy does not only make sense from an efficient material use & circular economy perspective but also from a GHG perspective as the best CO2 is the CO2 not emitted. The most effective way to reduce CO2 emissions is by preventing waste generation in the first place, thereby preventing the CO2 emissions associated with production processes. Reuse is the next best option, as it typically results in lower CO2 emissions compared to recycling, which still generates some emissions. When waste becomes non-recyclable, energy recovery with or without carbon capture and storage (CCS) is preferable to disposal, as it significantly reduces GHG emissions and more particular methane emissions. Methane, with its potent warming potential, accounts for about 90% of the waste sector's GHG emissions, contributing to 18% of global anthropogenic methane emissions.

Non-recyclable municipal solid waste comprises both biogenic (plant-derived, like food waste or non-recyclable paper) and non-biogenic (fossil fuel-derived, like non-recycable plastics) materials. Incinerating the biogenic components produces carbon-neutral CO2 emissions, while the non-biogenic parts contribute to CO2 emissions. Studies indicate a typical distribution of 60% biogenic and 40% non-biogenic CO2 emissions in WtE facilities.

Landfilling is a significant source of methane emissions, a GHG with a global warming potential 28 times that of CO2 over a century. WtE plants reduce methane emissions by incinerating organic waste that would otherwise generate methane in landfills. The Confederation of European Waste to Energy Plants (CEWEP) highlights a stark contrast in emissions: landfills produce about 600 kg CO2 equivalent per tonne of waste. While for WtE the emission factor is calculated to be -620 kg CO2 equivalent per tonne waste treated, taking into account energy substitution , bottom ash material recovery and landfill diversion.

The European Union (EU) serves as a compelling case study in managing municipal solid waste (MSW). Over the last three decades, the EU significantly reduced waste landfilling by approximately 60%, while increasing waste incineration and recycling/composting by around 100% and 200%, respectively. This shift has contributed to a more than 40% reduction in CO₂ equivalent emissions, demonstrating the substantial environmental benefits of moving waste management up the hierarchy from landfilling to incineration and recycling.

WtE combined with CCS technology is a carbon dioxide removal technology which can produce net negative emissions. When the biogenic portion of CO2 emissions from waste is captured and stored, it results in carbon removal from the atmosphere. As a rule of thumb every ton of waste incinerated creates 1 ton of CO2 emissions. For instance, with a typical biogenic to non-biogenic waste ratio of 60 to 40%, WtE with CCS can generate net negative emissions of 500 tonnes for every 1000 tonnes of waste treated. The global potential for negative emissions from WtE with CCS is substantial, with estimates suggesting several tens of millions of CO2 per year could be captured.

State-of-the-art carbon capture technology captures over 90% of CO2 emissions. There are already WtE plants capturing hundreds of thousands of tonnes of carbon annually and tens of CCS projects are being developed in the WtE sector. However, the widespread deployment of this technology faces challenges like high energy costs, the need for stable financial frameworks, and sufficient transport and storage infrastructure.

These challenges are being addressed step by step clearing the path for rolling out carbon removals. A lot of R&D is focused on reducing the energy costs of capturing the CO2. Also optimised WtE-CC integration designs have proven to significantly reduce the energy costs of carbon capture. WtE projects with CC are changing their business model by collecting revenue from carbon removal credits through capturing and storing biogenic CO2 emissions. The European Commissions is clear in its ambitions to roll out CO2 transport network across Europe to connect emitters with storage sites.

In conclusion, the integration of Waste-to-Energy and carbon capture technologies offers a promising path to mitigate climate change by addressing non-recyclable waste and reducing GHG emissions. Immediate and sustained efforts in this direction are essential to meet global climate targets and ensure a sustainable future.

About Keppel Seghers:

Keppel Seghers is a global technology supplier for the WtE installations. At Keppel Seghers, we believe that every WtE plant in the future will be equipped with carbon capture, also plants which are being constructed now. In this regard, Keppel Seghers developed a unique carbon capture ready WtE design allowing to integrate a carbon capture to your waste to energy plant, now and in the future.

As energy is the dominant cost of carbon capture, two factors are critical to reduce these energy costs one is selecting the appropriate CC technology and two is having an optimised WtE-CC integration. Keppel Seghers has supported multiple clients in selecting the appropriate technology for their WtE project. Through its know-how on both WtE and CC, KS has developed an optimised integration design to minimise the energy costs and other costs. Want to know more, reach out to us via info.keppelseghers@keppel.com

[1] European Commission, “Waste Framework Directive.” [Online]. Available: here [Accessed: 29-Apr-2024].

[2] F. Giouse, E. Ravache, and L. Moutte, “Détermination des contenus biogène et fossile des ordures ménagères résiduelles et d’un CSR,” 2020.

In cooperation with Keppel Seghers