A cautious approach to large-scale energy from waste (EfW) planning has been called for by a panel of industry experts.
Ian Williams, professor in engineering and environment at University of Southampton, which runs one of the largest waste management research groups in the UK, said at RWM 2013 that waste quantities in the UK are dropping.
A decade ago there was around 330 million tonnes of waste. Now there are just over 200 million tonnes, according to Williams (pictured above, far right).
He said: “It’s obvious that in another decade we are not going to have the quantities of waste that we think we are going to have. We have to be conservative in our building of EfW plants.”
He added that most contracts for EfW have been predicated on 2% year on year increases in waste arisings.
Williams said: “I think we are at 45% recycling - we can easily get to 65%. That would remove that feedstock and there’s a business trend to close the loop of resources - again reducing feedstock.”
The panel agreed that the industry is rapidly transforming and that EfW developers need to take account of this, especially when it comes to risky larger scale plants.
In another warning, Williams said that the calorific value of all waste is also dropping because some of the most calorific wastes, such as food and textiles, are gradually being removed from waste streams.
He also highlighted that the more recyclates are removed from waste streams the less that is known about the composition of the material that is left, and said arguments on the long-term viability of EfW have to take this into account.
But Andrew Howe, technical director of consultancy SKM Enviros (pictured above, centre), said that in municipal waste composition, high calorific value kitchen waste is increasing faster than plastic and paper waste is decreasing.
He added: “From the municipal point of view the calorific value may be going up.”
Adam Read, practice director, waste management and resource efficiency, at consultancy Ricardo AEA, said: “There are a number of different technologies EfW spans: mass burn incineration, combined heat and power, anaerobic digestion, pyrolysis and gasification. Each of these has different feedstock requirements.
“Therefore composition has different risk profiles depending on your preferred technology so it’s a complicated situation with limited data, increasing competition and more complexity.”
Overall, the panel agreed there is a role for EfW, but the focus should be smaller scale and bespoke to industries that have a relatively long lifetime and a relatively continuous feedstock.
Howe said there is greater scope for more front-end sorting going to either anaerobic digestion or gasification as well as smaller scale EfW plants, which can have more flexibility to manage the waste compositions and produce a steadier calorific value fuel.
Williams concluded that a lack of guidance from central Government on both waste and energy policies is complicating the matter: “There’s a lack of leadership and direction. Everybody else is waiting for everybody else to react.”