The Scottish Environmental Services Association (SESA) has today (5 Oct) voiced ‘concerns’ about a recent new report, published by Zero Waste Scotland (ZWS), that it says draws a ‘fundamentally unfair’ comparison between energy recovery infrastructure and other sources of low-carbon energy generation.
SESA says it is concerned the report advocates both maintaining Scotland’s current landfill rates, and the use of Mechanical Biological Treatment (MBT) to treat residual waste over energy recovery – a ‘seemingly retrograde step’, it says, which it believes is ‘at odds’ with more than a decade of waste policy development.
The report, ‘The climate change impacts of burning municipal waste in Scotland’, describes the climate change impacts of burning residual municipal waste in Scotland and aims to ‘inform and support’ evidence-based decisions to minimise the climate change impacts of managing residual waste, according to Zero Waste Scotland (ZWS).
The study quantifies the climate change impacts of burning residual municipal waste in Energy from Waste (EfW) plants in Scotland in 2018 and measures climate change impacts in two ways: carbon intensity and greenhouse gas emissions.
Carbon intensity is a standard approach for comparing the climate change impacts of different energy generation technologies, according to ZWS.
The carbon intensity of EfW plants are compared to the UK national grid average, with results showing that the carbon intensity of EfW plants is ‘twice as high’ as the grid average.
The alternative to EfW is not wind power but landfill, and therefore an unfair comparison in considering the low carbon merits of EfW
EfW carbon intensities would remain above the grid average even the plants were converted to Combined Heat and Power systems, according to the report, which ZWS says demonstrates that EfW can ‘no longer be considered a low carbon technology in the UK’.
The study also considered greenhouse gas emissions using a Life Cycle Assessment approach. The carbon impacts of sending one tonne of residual municipal waste to either EfW or landfill were compared.
Average EfW impacts were 15% lower than landfill in 2018. However, changes in waste composition mean that EfW impacts are expected to rise, it says.
Small changes in composition could push EfW impacts above landfill, leading to ‘unnecessary climate change emissions’, ZWS says.
The report has been reviewed by members of the Scottish Waste Data Strategy Board and includes discussion about where improvements in publicly available data could support accurate and ongoing monitoring of the carbon impacts of burning waste in Scotland.
ZWS says the study provides a ‘strong evidence base’ to ensure future long-term infrastructure and policy decisions are adapted to take advantage of significant opportunities to reduce the climate change impacts of waste.
Deeply surprised
SESA Policy Advisor, Stephen Freeland, says he is ‘deeply surprised’ by the recommendation in the report that the best option for Scotland’s residual waste is to maintain current rates of landfill.
He said the resources and waste management industry continues to make considerable investment in Scotland’s recycling capacity while at the same time investing in alternative residual waste treatment options, essential for diverting waste from landfill in compliance with Scotland’s 2025 landfill ban.
“Zero Waste Scotland’s research usefully points to the fact that energy from waste (EfW) delivers carbon savings over disposal of waste in landfill,” he said.
“The research also confirms the potential for greater carbon savings and efficiencies through the deployment of Combined Heat and Power (CHP). All EfW plants in Scotland are designed to be CHP-ready and operators actively explore options to connect with heat customers.
“Public policy could assist in this regard by helping to secure delivery in off-site heat infrastructure (such as local heat pipe networks or connections to heat customer premises) and ensuring that EfW-CHP is better integrated into the built environment.
“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.
“The alternative to EfW is not wind power but landfill, and therefore an unfair comparison in considering the low carbon merits of EfW. However, the industry is fully committed to net zero carbon and ESA is developing a carbon strategy to help demonstrate where emissions in the waste sector can be reduced, including EfW.”