Carbon capture is a technology that is being increasingly considered as the best way to reduce greenhouse gas emissions from waste incineration. Energy from Waste (EfW) is a process in which municipal solid waste is burned to generate electricity. However, this process also releases CO₂ and other greenhouse gases into the atmosphere, contributing to global warming. Carbon capture is a way to mitigate this by capturing the CO₂ emissions before they are released into the atmosphere.
It is important to differentiate the CO₂ generated by energy from waste into two categories according to its origin – fossil CO₂ from the combustion of fossil-based waste, such as residual plastics, and biogenic CO₂ from the biogenic fraction of different waste streams, such as residual paper and cardboard, wood, leather, food, and green residues that are contaminated and thus non-recyclable. The latter offers significant opportunities for EfW plants. There are over 500 EfW energy plants operating across the EU, more than 50 just in the UK, and in many cities, these are among the largest emission point sources. Many plants have already made plans to install CO₂ capture, driven by ambitious decarbonization targets and the lack of alternative options to decarbonize and remain an integral part of the UK government’s Net Zero Strategy. According to the UN IPCC Report AR6, the integration of EfW and Carbon capture, utilization and storage (CCUS) could enable waste to be a net zero or even net negative emissions energy source, thus an industry leader in decarbonization efforts.
There are several different types of carbon capture technologies, but the most applicable in waste incineration is amine-based post-combustion capture, which is also the most mature carbon capture technology on the market. In this process, the flue gases from the incineration process are passed through an absorber column, where the CO₂ is captured using a solvent. The captured CO₂ can then be stored underground or utilized in other industrial processes. Given that around 40-60% of the incinerated waste streams are of biogenic origin, there is prominent potential for the plant to provide CO₂ removal through BECCS – bioenergy combined with carbon capture. In November 2022, the European Commission published its Carbon Removal Certificate proposal, which is likely to guide the future generation of carbon removal certificates and provide crucial frameworks and revenue.
Advantages, challenges, and incentives
One of the main advantages of carbon capture in EfW is that it allows for the continued use of this energy source while reducing its environmental impact. Without carbon capture, elements of waste incineration would have to be phased out in order to reduce CO₂ emissions. However, with carbon capture, waste incineration can continue to be used as a source of energy while also reducing greenhouse gas emissions.
One of the main challenges of carbon capture in waste incineration has been the lack of incentives to capture the CO₂ which remains outside of the UK ETS and EU ETS except for in Denmark and Sweden. However, EU trilogues on the ETS element of the Fit for 55 policy package have already confirmed that EfW will be included in the carbon pricing scheme, with the aim of including it from 2028, with a possible opt-out until 31 December 2030. Several sources have already indicated the UK is due to follow suit in a similar timeframe. The expansion of the UK ETS to include EfW facilities will have a significant impact on the nature and extent of EfW operators' obligations and liabilities. As such, UK EfW operators would also be well advised to follow developments closely. The implications of this change will have a broad impact across the value chain including Local Authorities, other waste disposal authorities, and companies involved in the collection and disposal of municipal waste.
The application of a carbon price to EfW facilities in the EU and/or the UK will encourage further consideration of how decarbonization technologies and practices can be developed to reduce ETS liabilities and contribute to emission reduction targets. The future inclusion in the EU/UKA ETS coupled with ambitious decarbonization targets and carbon dioxide removal generation through BECCS presents significant incentives for both existing and new plants to install carbon capture technology in their facilities. Furthermore, steps need to be taken to ensure a stable and high enough ETS to provide predictability to emitters and investors. An ETS price floor, or government guarantee such as a carbon contract for difference can provide higher certainty.
Central to the EfW operators’ business case is whether exposure to the ETS prompts the emitter to store the CO₂, thereby being exempt from the ETS, or if it is more commercially viable to sell the CO₂ for higher than the cost of the ETS price.
The inclusion of EfW in the ETS is not a question of “if” anymore, but rather “when” – essential to the inclusion is an interim period of Monitoring, Reporting and Verification (MRV).
The approach to MRV is important as it may impact on the extent and cost of an operator's UK ETS compliance obligation. It is highly likely that inclusion in the UK ETS will cover the incineration of fossil material only (biogenic material would be excluded). This would mean that UK ETS allowances would only need to be acquired and surrendered in respect of fossil material incinerated at EfW facilities, and any biogenic capture would then qualify as a carbon credit, which could be traded.
From March to June 2022, the UK government ran the “Developing the UK Emissions Trading Scheme (UK ETS) consultation”. The consultation puts forward two options that could be used in determining the MRV obligation for each facility, namely:
- An 'Individual facility monitoring' approach - requiring individual operators to determine the ratio of fossil and biogenic CO₂ that is being emitted from their facilities themselves either via radiocarbon methods or a 'balance method' looking at data on chemical composition; or
- An 'Emissions factor approach' - involving the use of an estimate for the composition of waste. This could be set at either a national or regional level, or each facility could derive its own emissions factor based on international standards. Emissions from burning fossil material (which would be required to determine an operator's UK ETS obligation) would then be calculated by multiplying the number of tonnes of waste processed by the emissions factor.
Aker Carbon Capture and waste-to-energy
Waste incineration is one of four prioritized industry segments for Aker Carbon Capture. Our proprietary patented technology has been developed over 20 years and is validated through over 50,000 operating hours and verified for several applications, including EfW.
Aker Carbon Capture’s technology is cost-effective, robust and flexible, meaning it can be applied to existing plants or new builds. The process uses a biodegradable mixture of water and organic amine solvents to absorb the CO₂ and has a market leading HSE profile. Today, Aker Carbon Capture is delivering a standardized Just Catch™ modular carbon capture on an EfW project that will start capturing 100,000 tonnes of CO₂ per year, from the end of 2023. The project is located in the Netherlands, at Twence’s waste-to-energy plant in Hengelo, where construction is progressing. The plant will reduce CO₂ emissions associated with the generation of energy from the incineration of non-recyclable waste. The captured CO₂ will be used to boost production in greenhouses. This is a unique example and an important part of a circular economy.
Carbon capture technology in waste incineration is a needed solution for reducing greenhouse gas emissions. It is inevitable that EfW operators will need to install CCUS technologies to meet the government’s emissions targets in the near future. It is a sustainable way to generate energy from waste while reducing the environmental impact. The cost and energy consumption of the carbon capture process are still challenging, but these are improving especially through solutions such as Aker Carbon Capture’s Just Catch™, which has driven down the cost through standardization and modularization. The incentives that were once lacking for the EfW industry will shortly become a reality, while biogenic CO₂ and generating negative emission credits have never seen more momentum.