Climate Change

EfW potentially more damaging than landfill

Zero Waste Scotland (ZWS) has published a report highlighting the negative climate impacts of the energy-from-waste (EfW) process of energy generation.

The climate change impact of burning municipal waste in Scotland measured the impacts of burning municipal waste in six of Scotland’s EfW plants in terms of carbon intensity and greenhouse gas emissions.

This study finds that the carbon intensity of the country’s EfW plants was twice as high as the UK national grid average, which it says contradicts any claim that it can be considered a low-carbon technology.

Iain Gulland, chief executive of Zero Waste Scotland, commented: “While energy from waste may have been ‘low carbon’ in previous decades when Scotland, and the UK, had a much more carbon intensive energy system, rapid and continuing decarbonisation has changed the equation. Our study shows that energy-from-waste can no longer be considered a source of ‘low carbon energy’ in the UK, and especially not in Scotland, which has one of the world’s lowest carbon electricity systems.”

Whilst carbon impacts - per tonne of municipal waste - were found in 2018 to be 15 per cent lower than those from landfill, greenhouse gas emissions from EfW were shown to be rising due to ongoing change in waste composition and potentially could exceed the impact of landfill. It estimates that if the composition of plastic in municipal waste increases by 2 per cent to 17 per cent overall, then this would mean the current EfW plants in Scotland would produce a higher level of climate change emissions than landfill.

The study has been commissioned by ZWS to inform future policy making and investment in waste infrastructure about the climate change implications. It considers different scenarios that can result from the Scottish Government ban on sending biodegradable municipal waste to landfill from 2025.

A central feature of the reports analysis is the role using heat from EfW facilities can play in reducing their overall climate change footprint, advocating that Scotland’s existing incinerators are converted to Combined Heat and Power (CHP).

In addition, of the scenarios modelled, the report states that the use of mechanical biological treatment (MBT) to pre-treat residual waste, prior to the use of EfW plants converted to CHP would result in the least impactful in terms of greenhouse gas emissions.

The finding of the report has been welcomed by the anti-incineration campaign, UKWIN. Shlomo Dowen, National Coordinator of UKWIN, said: "The report rings the alarm bells about incineration, warning that if we are serious about Net Zero 2050 then we need to stop looking to CO2-belching incinerators and focus instead on the top tiers of the Waste Hierarchy.

“Incineration is not only inefficient and highly polluting, it is a terrible waste of resources and very expensive. Scotland needs to live up to its zero waste and climate change ambitions, and that means the Government needs to stop allowing new incinerators to be built as that puts Scotland's progress in jeopardy."

The report has also been met with criticism by the Scottish Environmental Services Association (SESA) on account of its “fundamentally unfair comparison between energy recovery infrastructure and other sources of low-carbon energy generation”.

SESA has also voiced concerns about the report advocating for maintaining Scotland’s landfill rates in its comparison of EfW to landfill, which the organisation deems “a seemingly retrograde step at odds with more than a decade of waste policy development”.

Another area of concern, according to SESA, is that the report promotes the use of MBT to pre-treat residual waste for landfill over energy recovery.

Stephen Freeland, Policy Adviser at SESA, commented: “Zero Waste Scotland’s research usefully points to the fact that EfW delivers carbon savings over disposal of waste in landfill.

“However, we are deeply surprised by the recommendation that the best option for Scotland’s residual waste is to maintain current rates of landfill, and subject residual waste firstly to an MBT process.

Experience elsewhere tends to point to the limitations of Mechanical Biological Treatment (MBT), while its outputs would likely be challenged to meet the stringent respiration thresholds of Scotland’s 2025 landfill ban. The ZWS report is also strangely at odds with Scottish Government policy which is rightly aimed at diverting waste from landfill.”

In response to these concerns, Gulland said: “Our study does show that energy recovery remains slightly preferable to landfill under current conditions, but this is highly sensitive to relatively small changes in waste composition.

“The challenge, as always, is to continually look to reduce waste as much as possible, recycle and reuse as much of what remains consistent with a shift to a circular economy, thus negating any need for unsustainable disposal regardless of technology.

“The report shows how Scotland could have reduced the carbon impacts of residual waste in 2018. Zero Waste Scotland is and has always been committed to supporting the country to meet its 2025 waste targets, and this report does not recommend maintaining residual waste at 2018 levels.

“Zero Waste Scotland has always been clear that we should reduce waste as much as possible, recycle as much as possible of what remains, and only then, treat the remaining residual waste using the lowest carbon options available.”

The role of EfW in Scotland’s waste strategy has recently been subject to scrutiny, following Eunomia’s report for the Scottish Government. It concluded: “It would be wise to limit development of new thermal treatment capacity to that required once any targets have been met to avoid creating overcapacity as recycling increases."