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| Fig. 1: EU municipal waste. (Image source: A. Schechter, after Eurostat. [2]) |
The European Union has relied on Waste-to-Energy (WtE) practices, in particular incineration, over the last several decades as a more sustainable approach to managing its waste. Particularly, as shown in Fig. 1, incineration with energy recovery has emerged as a pivotal strategy. However, as the EU shifts towards a circular economy, WtE has been receiving bad press because of its environmental and human health impact. In this paper we explore the energy produced by WtE in the EU and deliberate on its future in the context of energy needs for the continent as well as its sustainable development goals. [1]
As shown in Table 1, from 1995 to 2021, municipal waste incineration rose by 106%, reaching 62 million tonnes. This trend aligns with a decline in landfilling, which decreased by 56% over the same period. The shift from landfilling to WtE was driven by legislative measures such as Directive 31/1999, which mandated a reduction in landfilling of biodegradable waste. The EU's Circular Economy Package will likely continue this trend away from landfills by setting ambitious recycling targets and imposing stricter limits on landfilling. [2]
WtE does have environmental benefits, such as diverting waste from landfills and reducing the EUs reliance on fossil fuels. However, there are several environmental concerns as well. The incineration process releases significant amounts of CO2, particularly from the fossil-based components of waste, like plastics. Because of the shift from landfill to WtE, emissions that were historically tracked under the waste sector are now being categorized under the energy sector. So while landfills are reducing emissions, WtE has doubled. In 2018, WtE plants in the EU emitted around 95,425 kt CO2. Consequently, the EU's support for new WtE incinerators has waned, reflecting a growing concern about their carbon footprint. [3]
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| Table 1: Municipal waste treatment practices (kg per capita), [2] |
In addition to the Carbon dioxide concerns, there are other dangerous emissions such as dioxins, furans, and particulate matter that are released from WtE. These emissions often go unreported and with little enforcement. [1] While new technology can reduce these pollutants, there is evidence that its hard to fully prevent contamination from nearby environments. [4]
Incineration for WtE involves the burning of waste to produce energy. Because the waste contains materials with carbon atoms, when burned these carbon atoms are released as carbon dioxide and heat. The generated heat is used to produce steam, which generates electricity. There are some facilities that combine heat and power production, in these facilities the heat is used both for generating electricity and for distributing residual steam through a heating network. While the efficiency of energy conversion varies, high-performance incinerators can achieve 25-30% efficiency in converting heat to electricity, and up to 85% for heat utilization. [5] Given the low electricity efficiency, the energy yield from waste is lower when compared to conventional fuels. Below, we find the amount of energy that 62 million tonnes of waste produces and compare it to oil.
EPA estimates suggest that waste incineration produces between 470 to 930 kWh per 1 ton of MSW. [6] With these values, we calculate that the energy generated by 62 million tonnes of waste (converted to joules since 1 kWh = 3,600 kJ):
| Lower Range: | 62M tonnes × 470 kWh/tonne = 29.14B kWh = 1.05 × 1017 J | |
| Upper Range: | 62M tonnes × 930 kWh/tonne = 57.66B kWh = 2.08 × 1017 J |
As comparison, the energy content of a barrel of oil is shown below. The energy content of one barrel of oil is approximately 6.1 × 109 J, so the equivalent number of barrels of oil are [7]
| Lower Range: | 1.05 × 1017 J 6.11 × 109 J/bbl |
= | 1.72 × 107 bbl = 2.3 × 106 tonnes of oil | |
| Upper Range: | 2.08 × 1017 J 6.11 × 109 J/bbl |
= | 3.40 × 107 bbl = 4.6 × 106 tonnes of oil |
This means the energy produced from incinerating 62 million tonnes of municipal waste in the EU is equivalent to the energy content of approximately 2.3M to 4.6M barrels of oil, depending on the efficiency of the waste-to-energy process. While these numbers may appear large, WtE actually makes up a very negligible amount of energy produced in the EU. The main function for WtE is to serve as a waste management practice and WtE does provide an alternative to traditional landfill practices that are more space consuming. WtE significantly reduces the volume of waste that ends up in landfills. Incineration can reduce the volume of waste by up to 75-90%, thereby conserving land and reducing the environmental impact associated with landfills, such as groundwater contamination and methane emissions. [8]
WtE incineration has played a significant role in the EU's waste management framework. It also provides an energy recovery and reduces landfill use. However, WtE does have substantial downsides, its efficiency in energy conversion is lower compared to conventional fuels like oil. It also has serious environmental and human health concerns. Despite these concerns, when WtE facilities operate in compliance with the latest safety standards and employ advanced emission control technologies, they represent a more favorable option than landfilling. For these reasons WtE should continue to play a role in the EUs waste management practices until a better alternative waste management solution is developed.
© Aline Schechter. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
[1] "Waste to Energy," United Nations Environment Programme, 2019.
[2] "Municipal Waste Statistics," Eurostat, August 2023.
[3] J. Vahk, "Landfill Emission Reductions Only Tell Half the Story as GHG Emissions From Waste-to-Energy Incineration Double," Zero Waste Europe, November 2020.
[4] A. Arkenbout, "Hidden Emissions: A Story From the Netherlands," Zero Waste Europe, November 2018.
[5] A. Ballinger et al., "Greenhouse Gas and Air Quality Impacts of Incineration and Landfill," Eunomia, December 2020.
[6] P. O. Kaplan, J. DeCarolis and S. Thorneloe, "Is It Better to Burn or Bury Waste For Clean Electricity Generation?" Environ. Sci. Technol. 43 1711 (2009).
[7] "BP Statistical Review of World Energy 2022," British Petroleum, June 2022.
[8] "Energy, Transport and Environment Statistics, 2020 Edition," Eurostat, October 2020.