The European waste hierarchy pyramid(1) presents the different actions to manage waste from the most sustainable one to the least sustainable one. The last two steps, waste incineration for energy recovery and waste disposal through landfills must be avoided because of the associated material destruction and greenhouse gas emissions.
On the material point of view, following the evolution of waste incineration and disposal indicates how far Sweden is from a circular economy. In a circular economy, the materials should stay in use as long as possible and then be reused so that waste incineration and disposal quantities should tend to zero.
On the climate change point of view, waste incineration and waste disposal are important contributors to greenhouse gas emissions. This article will go through the available data and analyse the trends and evaluate the effort needed to reach the climate goal of net-zero-emissions of greenhouse gas.
How are greenhouse gas emissions computed and reported?
There are different ways of reporting greenhouse gas emissions depending mainly on their geographical scope.(2)
The territorial emissions are calculated on the basis of the activities within Sweden's borders and used to follow up on the climate goals set for Sweden. Sweden's long-term climate goal is that greenhouse gas emissions within Sweden's borders must reach net zero by 2045. In this article, we will study the territorial emissions related to waste.
The consumption emissions are calculated on a model-based estimation of the Swedish consumption emissions. More information about the different methods are available on Naturdvårdsverket website.
The following chart shows the evolution of territorial and consumption based emissions since 1990.
Total territorial emissions
The Swedish Environmental Protection Agency publishes Sweden's official statistics for greenhouse gas emissions for 2019. The total of the territorial emissions were 50.9 million tonnes of carbon dioxide equivalents.(3)
Emissions of greenhouse gases from waste treatment
The greenhouse gas emissions from waste treatment have decreased by 71% since 1990. In 2019, the emissions amounted to 1094 thousand tons of equivalent C02 in the sector, representing 2.2% of Sweden’s total territorial greenhouse gas emissions. The emissions from the sector waste treatment are divided into four categories and the following figure shows the evolution of greenhouse emissions from waste treatment for the last 30 years.(4)
57% of the emissions come from one category, namely landfills and methane emissions. What ends up in landfills are waste from both households and industries, ashes from electricity and heat production as well as contaminated soil masses. Since 1990 the methane emissions from landfills have decreased by 81%. This is due to the increase of methane recovery, the decrease of landfilled organic waste as well as the increase of waste incineration and material recycling.
21% of emissions from waste treatment are emissions of nitrous oxide and methane from wastewater treatment and sludge. Since 1990 these emissions have decreased by 11% as a result of improvements in treatment plants and increased biogas production.
12% of the emissions comes from the incineration of hazardous waste (for destruction). The incineration of hazardous waste (such as chemical, oil and mixed waste and electrical and electronic equipment waste) generates emissions of carbon dioxide, nitrous oxide and methane emissions. Since 1990 the emissions from this category have increased by 179% as a result of an increased total production of hazardous waste as well as increased incineration capacity.
Finally the last 10% of emissions from waste treatment comes from the biological treatment of solid waste, namely from the production (leakages) of compost and biogas. The emissions from this category have increased by 400% since 1990 as a result of increased composting and anaerobic digestion as well as increased investments in the construction or expansion of biogas plants. It is also worth noting that emissions from the use of biogas are reported in the other sectors where biogas is used and not in the sector of waste treatment.
Transfer of emissions from one sector to another
The decrease of greenhouse gas emissions from the sector of waste treatment is mainly a result of the decrease of emissions from landfills. Landfill bans and landfill taxes have been implemented resulting in less waste into landfills but more waste sent to incineration instead. Waste is incinerated in order to produce electricity and heating, which also generates greenhouse gas emissions. These emissions are reported in the energy sector (electricity and district heating production).
Emissions of greenhouse gases from electricity and district heating
In most district heating networks, fossil fuels and peat have been replaced by waste incineration. The greenhouse gas emissions have been reduced since 1990 and are now stable around a bit above 4000 thousand tons of equivalent C02. The following figure shows the evolution of greenhouse emissions from electricity and district heating for the last 30 years.(5)
Reported greenhouse gas emissions from waste incineration come mainly from plastic, which is produced almost exclusively from fossil oil and natural gas. The following figure shows the evolution of greenhouse emissions from waste incineration for the last 30 years.
The emissions from waste incineration has been multiplied by a bit more than 5 in 30 years as illustrated by the chart above. In 2019 emissions from the fossil part of the waste corresponded to 64% of the electricity and district heating sector's emissions and 5,8% of the total territorial emissions. The trend will continue to increase as more incinerators will be built.(6)
Only the estimated greenhouse emissions coming from fossil sources are counted in the national statistics. The emissions coming from biomass sources are considered as “climate neutral” and are not reported in this statistic. This means that the incineration of waste composed of biomass like cardboard, paper or food waste is not accounted. This way of reporting greenhouse emission for forest biomass has been discussed in research, as the recapture of carbon from forest regrowth spans over several decades and depends on the overall forest management strategies.(7) Aside from its climate change impact, the Swedish forestry industry has recently been criticized for the management of forest ecosystem and biodiversity by NGOs and environmental experts.(8)
Within/In the United Nations Framework Convention on Climate Change (UNFCCC) statistics database (9) Sweden reported 3’889 tonnes eq C02 from waste incineration of biomass and 2’410 tonnes eq C02 from waste incineration of fossil fuels.
From the UNFCCC database, we can compare the overall greenhouse emissions in 1990 and 2018.
Total 1990 without Biomass incineration = 0.5 + 3.42 + 0.01 + 0.04 = 3,97 Mt C02 equivalent
Total 2018 without Biomass incineration = 2.41 + 0.78 + 0.11 + 0.13 = 3,43 Mt C02 equivalent
When taking into consideration the total emissions reported in waste treatment and waste incineration, the total greenhouse emissions only decreased from 3,97 Mt to 3,43 Mt in 28 years. Today it represents 6,73% of the territorial greenhouse emissions of Sweden. While greenhouse emissions from waste management are decreasing, the greenhouse emissions from waste incineration are growing, summing up in relatively stable emissions from 1990.
The incineration of plastic is the main part of the overall greenhouse emissions. The emergency for this sector is to develop reusable packaging solutions in order to reduce the amount of waste incinerated. The waste-to-energy infrastructures are far from being low carbon and since they are built to last for 20-25 years, the promotion of incineration solutions is delaying the decarbonisation effort in Sweden.
(1) “Waste prevention and management - Environment”, European Commission https://ec.europa.eu/environment/green-growth/waste-prevention-and-management/index_en.htm
(2) “Tre sätt att beräkna klimatpåverkande utsläpp”, Naturvårdsverket. https://www.naturvardsverket.se/Sa-mar-miljon/Klimat-och-luft/Klimat/Tre-satt-att-berakna-klimatpaverkande-utslapp/
(3) “Sveriges officiella statistik - Nationella utsläpp och upptag av växthusgaser”, Naturvårdsverket. https://www.naturvardsverket.se/Sa-mar-miljon/Statistik-A-O/Vaxthusgaser-territoriella-utslapp-och-upptag/.
(4) “Utsläpp av växthusgaser från avfall”, Naturvårdsverket. https://www.naturvardsverket.se/Sa-mar-miljon/Statistik-A-O/vaxthusgaser-utslapp-fran-avfall/
(5) “Utsläpp av växthusgaser från el- och fjärrvärme”, Naturvårdsverket. https://www.naturvardsverket.se/Sa-mar-miljon/Statistik-A-O/Vaxthusgaser-utslapp-fran-el-och-fjarrvarme/
(6) "Kraftvärmeverket i Lövsta får ny tung kritik - Mitti." https://www.mitti.se/nyheter/kraftvarmeverket-i-lovsta-far-ny-tung-kritik/repucD!OJXgeQ8U@F0Nre3hkobUw/
(7) “Biomass energy: green or dirty?”, Physics World. https://physicsworld.com/a/biomass-energy-green-or-dirty/
(8) “More Of Everything - A film about Swedish forestry”, YouTube, https://www.youtube.com/watch?v=q51FMbTOn_Q
(9) “Greenhouse Gas Inventory Data - Flexible Queries Annex I Parties”, United Nations Framework Convention on Climate Change. https://di.unfccc.int/flex_annex1