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UKWIN Climate Change Reports

Climate Change Reports:

Good Practice Guidance for Assessing the GHG Impacts of Waste Incineration

This good practice guide provides recommendations for assessing GHG impacts of waste incineration. It is intended to be used by those carrying out such assessment as well as those reviewing or determining how much weight to give those assessments. The guide was created due to the inconsistent quality of such assessments (including those used to inform planning, permitting and policy decisions), and highlights areas where there is a genuine risk that adverse impacts of waste incineration could be significantly understated or misrepresented.

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Presentation from a workshop on the guidance:

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The analysis found that for the incinerators studied, on average:

1. The proportion of CO2 that was fossil CO2 was 13 percentage points higher than predicted at the planning or permitting stage.

2. The fossil carbon intensity of electricity exported to the grid was around 49% higher than predicted by the applicant at the planning or permitting stage

3. Reported fossil CO2 released per tonne of waste feedstock incinerated was around 20% higher than that predicted at the planning or permitting stage.

4. Electricity generated by incinerators was 15% lower than implied by the claimed headline megawatt (MW) generation figure, i.e. an incinerator advertised as being capable of generating 10MW of electricity typically only generated 8.5MW.

5. Electricity exported was around 28% lower headline MW generation figures.

Key recommendations of the guidance:

1. Methodology and modelling assumptions, including underlying data and how it was derived, should be transparent and verifiable. Scrutiny of environmental claims made to support waste incineration should be facilitated rather than frustrated.

2. Key outputs such as power export and greenhouse gas (GHG) emissions are dependent on waste composition and the processes used. When modelling future emissions it is necessary to ensure that outputs are internally consistent with inputs.

3. GHG impacts can be highly sensitive to waste composition. Waste composition assumptions should be justified and sensitivity analysis should be used to show the impacts of future changes such as increased food and biowaste collection. 

4. While heat export, carbon capture, and pre-treatment to remove plastics can potentially reduce overall GHG impacts of incineration, there are also uncertainties regarding deliverability and/or overall impacts. Sensitivity and lifecycle analysis can be used to explore a range of possibilities and to reflect relevant uncertainties.

5. To produce a valid comparison when comparing waste treatment options such as landfill and incineration that release different quantities of biogenic CO2 it is necessary to account for these differences, especially the impact of the biogenic carbon sink in landfill.

6. The carbon performance of modern waste incinerators is often significantly worse than was predicted through modelling at the planning and permitting stages. This discrepancy between predicted and actual carbon performance needs to be taken into account when modelling, and robust sensitivity analysis is needed to ensure that CO2e emissions from incineration are not significantly underestimated.

7. Power export underperformance, e.g. due to turbine or generator failure or during commissioning, is a realistic prospect for modern waste incinerators that needs to be taken into account when modelling anticipated power output and associated climate impacts.

8. When considering the carbon intensity of displaced energy it is necessary to take account of the progressive decarbonisation of the energy supply rather than simply assuming that a new energy source would displace fossil fuels. The carbon intensity of electricity displaced by a new incinerator can be estimated using the average BEIS Long-Run Marginal Emissions Factor (MEF) over the lifetime of the plant.

9. When considering how waste would be treated if it were not sent to an incinerator, account should be taken of the prospect that it might otherwise have been reduced, reused, recycled or composted. Account should also be made of how landfilled waste could be bio-stabilised to reduce methane emissions.

10. Energy from mixed waste incineration should not be described as ‘low carbon’. Incineration involves the direct release of significant quantities of CO2.

Evaluation of the climate change impacts of waste incineration in the United Kingdom

This report evaluates the climate change impacts of waste incineration and is intended to inform policy makers, decision-takers, and the public. The need for this study arises in response to the increasing quantities and proportions of UK waste that are incinerated and the necessity to consider the outcomes arising from this increasing level of incineration alongside the various conflicting claims that are made about the climate change impacts of waste incineration.

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Based on the data and methods set out in the report, the study found that:
  • Waste incinerators currently release an average of around 1 tonne of CO2 for every tonne of waste incinerated.
  • The release of CO2 from incinerators makes climate change worse and comes with a cost to society that is not paid by those incinerating waste.
  • In 2017 the UK’s 42 incinerators released a combined total of nearly 11 million tonnes of CO2, around 5 million tonnes of which were from fossil sources such as plastic.
  • The 5 million tonnes of fossil CO2 released by UK incinerators in 2017 resulted in an unpaid cost to society of around £325 million.
  • Over the next 30 years the total cost to society of fossil CO2 released by UK’s current incinerators would equate to more than £25 billion pounds of harm arising from the release of around 205 million tonnes of fossil CO2.
  • Electricity generated by waste incineration has significantly higher adverse climate change impacts than electricity generated through the conventional use of fossil fuels such as gas.
  • The ‘carbon intensity’ of energy produced through waste incineration is more than 23 times greater than that for low carbon sources such as wind and solar; as such, incineration is clearly not a low carbon technology.
  • When waste is landfilled a large proportion of the carbon is stored underground, whereas when waste is burned at an incinerator the carbon is converted into CO2 and immediately released into the atmosphere.
  • Over its lifetime, a typical waste incinerator built in 2020 would release the equivalent of around 1.6 million tonnes of CO2 more than sending the same waste to landfill. Even when electricity generation is taken into account, each tonne of plastic burned at that incinerator would result in the release of around 1.43 tonnes of fossil CO2. Due to the progressive decarbonisation of the electricity supply, incinerators built after 2020 would have a relatively greater adverse climate change impact.
  • Composition analysis indicates that much of what is currently used as incinerator feedstock could be recycled or composted, and this would result in carbon savings and other environmental benefits. Thus, incinerating waste comes with a significant ‘opportunity cost’.

Reports and briefings from Zero Waste Europe