Although criticised by some, energy from waste is seen as a vital component of the UK’s waste management system. Chris Elliott looks at where it fits as we transition to a circular economy.
It’s one of the burning issues in the quest for a circular economy: is incinerating waste a good thing or not?
On one side of the argument, there are those who believe it can be a useful way of making energy, and that it’s preferable to landfilling. It’s also a way of destroying waste that cannot be managed in any other way, because the material involved is dangerous, such as infectious bio-wastes from hospitals, or hazardous wastes from industry.
Alternatively, some contend that energy from waste (EfW) is adding to pollutants being released into the air – and that we should be fixing our attention more on not generating so much waste in the first place.
Another key aspect of the debate is the export of waste from the UK to other countries. On one hand, the export of refuse-derived fuel (RDF) can be seen as playing an important and beneficial role in the management of our residual waste. However, materials shipped overseas for incineration are, in some cases, burned openly or crudely.
Typically, EfW involves burning materials at temperatures of more than 850°C. Often shredded, the waste is incinerated in a combustion chamber where oxygen is added. The heat generated can then be used to make electricity, and provide heat to local homes and businesses if the plant is a combined heat and power (CHP) facility. But the process also produces carbon dioxide, and despite assurances that emissions can be – and are – controlled, some critics still want EfW scaled back, or even halted.
To some campaigners it’s a black and white issue – but to those working in the resources sector, it’s not that simple. Circular has been speaking to waste industry experts to garner their views.
I see a future where activity further up the waste hierarchy will see the generation of less residual waste, especially if this is backed up by economic and other policy instruments
Mike Tregent, CIWM Chartered Environmentalist member with more than 30 years’ experience in waste regulation, and resource planning and strategy, says EfW’s position in the waste hierarchy correctly reflects its overall sustainability. ‘I see a future where activity further up the waste hierarchy will see the generation of less residual waste, especially if this is backed up by economic and other policy instruments,’ he says.
The Committee on Climate Change suggests the waste sector can reduce its carbon impact by 75 per cent, part of which would have to come from reduced emissions from EfW, says Tregent.
‘I support limited EfW/incineration because we need time to develop better, more circular systems, and because we need to destroy persistent chemicals. However, we should be strict on timeframes for reduction to facilitate more sustainable and efficient options.’
Tregent believes a number of factors need to be considered. He says: ‘Taking a science-based approach to future investment decision-making – and improving environmental, social and corporate governance [ESG] – will highlight the greater risks of EfW, in terms of the need for improved efficiency, carbon-capture use and storage, and potential changes in feedstock.’
Taking a carbon perspective, and a landfill-diversion perspective, he says, paints EfW in a favourable light. ‘However, full life-cycle assessment shows that more material is destroyed in the process (abiotic depletion) that can no longer be used again – for example, fossil-derived content such as plastic and some textiles.
‘As separate food collections ramp up, it’s more probable that waste will be treated via anaerobic digestion, which will reduce the biogenic content of the refuse-derived fuel feedstock, meaning more emissions will be fossil-based, reducing the renewable fraction.
‘Electricity-only EfW plants are single-cycle steam-power plants, limited to efficiencies from 35-42 per cent, compared with combined-cycle gas generators that operate at a thermal efficiency of around 64 per cent in base-load operation. CHP offers efficiencies of up to 70 per cent. Installation, however, can be costly and requires ready users to be nearby.’
Part of the transition
As well as being at the bottom of the waste hierarchy, landfill has a range of social, environmental and economic impacts. Nuisances such as flies, smells, smoke and noise are often cited as reasons why people do not want to live close to landfill sites. Environmental problems include the production of leachate and gases, which pose risks to human health, as well as landscape changes, displacement of fauna and loss of habitats – and studies have indicated that the proximity of landfill sites can have a negative impact on house values.
John Twitchen, CIWM Fellow and founder of env23, says EfW is not a binary issue. ‘The answer will be different in different places,’ he says. ‘However, what is clear is that EfW facilities are an important transition technology – they are part of the solution for reducing the social, environmental and economic impacts of landfill, not least, but most obviously, by reducing methane emissions.’
Twitchen says we are still failing to grasp the opportunity presented by existing and planned EfW facilities. ‘Decarbonising heat is a huge challenge, and EfW can play a part,’ he says.
He believes current EfW facilities in operation, construction and planning should not need to be replaced at the end of their useful life, by around 2050. ‘However, this relies on all organisations ending their wasteful habits by grasping reuse opportunities, embracing and owning circular economy solutions, and stopping the lame excuses for hanging on to what remains of the status quo,’ he says.
Policy and long-term clarity
Jacob Hayler, Environmental Services Association (ESA) executive director, says energy recovery remains a vita component of the UK’s waste management system.
By 2030, he adds, the pipeline of new energy-recovery infrastructure will save more than a million tonnes of CO2 equivalent from entering the atmosphere each year by diverting waste from landfill, which is more carbon intensive.
Although the recycling and waste sector accounts for a relatively small percentage of UK carbon emissions, Hayler says a new net-zero strategy for the sector will address the carbon intensity of recycling and resource management operations.
This will include the electrification of plant and vehicle fleets; investment in carbon capture and storage; driving more biogenic material out of landfill; and removing fossil-based materials from energy recovery, while maximising the efficiency of plants through greater heat offtake.
He thinks that emerging waste policies in the UK and the devolved administrations will drive the next step change in recycling performance and ‘help our sector remove more and more fossil-based materials from residual waste streams’.
The volume of residual waste in need of treatment will still necessitate energy recovery infrastructure well into the future, under even the most optimistic recycling scenarios, and the most ambitious policy interventions.
However, he adds, there will still be a place for EfW: ‘The volume of residual waste in need of treatment will still necessitate energy recovery infrastructure well into the future, under even the most optimistic recycling scenarios, and the most ambitious policy interventions.
‘Future EfW capacity and technology, however, is a balancing act for the market to respond to in the context of future policy – which is why long-term clarity of direction is so important.’
The landfill tax mechanism was effective at moving residual waste from landfill to energy recovery, says Hayler, ‘but it has not stimulated or supported recycling markets in the way we hope the emerging resources and waste strategy will’.
Increasing the proportion of waste materials that are recycled and reused requires more complex systemic shifts than the transition from landfill to energy recovery – but, says Hayler, these systems are rapidly moving in the right direction.
‘In the meantime, any kind of taxation on energy recovery will simply introduce additional costs for waste producers without driving more material further up the waste hierarchy,’ he says.
So, what, if any, is the consensus?
Experts’ opinions suggest EfW currently has a role to play – a role that will, hopefully, diminish as progressive policies by governments and new technology move us closer to a circular economy.
In 2019, a forum was established to look at the future of waste management in the UK, and at what role EfW could play in contributing to the government’s ambitions of achieving a circular economy.
Responding to the forum questions, CIWM stated that ‘most UK policies on EfW and residual waste are appropriate, having largely followed the waste hierarchy and, more recently, circular economy thinking, which are well-respected, scientifically based concepts underpinned by wider resource and life-cycle considerations.’
The institution added that key policy documents have presented the recovery of energy from waste – where applicable according to the waste type – as being generally preferable to disposal, including landfill. Such policy has also recognised that, while recycling sits higher up in the waste hierarchy, commercial and technical limitations will also place limits on what is realistically recyclable. As such, energy recovery has a role to play for some theoretically recyclable wastes for which there is currently no economically viable recycling route.
This article featured in the Jan / Feb issue of Circular.