What the review found
In 2024 Zero Waste Scotland published modelling suggesting Scotland could end up with 10 to 18% more energy-from-waste capacity than it needed. That finding fed the Scottish Government's effective moratorium on new plants. The August 2026 update, prepared by SLR Consulting, revisited it with current data and reached a different conclusion.
Permitted capacity across the fleet reaches around 2.37 million tonnes a year by 2028. Operational capacity, what the plants can actually process allowing for downtime, is 1.96 to 2.08 million tonnes. Against the residual waste Scotland produces, that leaves a shortfall of around 0.4 million tonnes in 2026, narrowing to 0.04 million tonnes in 2028, with a surplus only from 2029.
The headline: contrary to the 2024 analysis, the updated modelling does not indicate significant energy-from-waste overcapacity in Scotland under any scenario to 2035.
- Published August 2026 by Zero Waste Scotland
- Prepared by SLR Consulting for the Scottish Government
- Around 2.37 million tonnes permitted by 2028
- 1.96 to 2.08 million tonnes operational
- Shortfall 0.4 Mt in 2026, 0.04 Mt in 2028
- No significant overcapacity to 2035
The outage problem
Every plant shuts for maintenance. Operators schedule 14 to 21 days a year, and a larger 25 to 60 day outage every five to ten years. With the fleet running close to full, there is nowhere for that plant's waste to go while it is down.
The review's warning is specific: by 2028, commercial and industrial waste producers could be left without a viable thermal treatment outlet during scheduled outages. Theoretical headroom across the fleet is only 285,000 to 407,000 tonnes a year, and an unplanned shutdown eats it.
This is the mechanism behind the landfill ban enforcement delay. Banned waste is meant to go to these plants. When they cannot take it, it either goes to landfill under SEPA's temporary relief, or it goes south. Coordinating outages across the fleet is the review's practical recommendation.
Residual waste bill creeping up?
Sorted collections cut what goes for treatment. Scheduled trade service with a transfer note.
What this means in practice
For households, very little day to day. Council residual waste has contracted capacity and will be treated. What the review changes is the argument: the case against energy-from-waste on the grounds of overbuilding is weaker than it was, and our honest assessment in energy from waste in Scotland stands, including the criticisms.
For businesses producing residual waste, the review is a warning about 2027 and 2028. Commercial waste is the flexible part of the system, the part that gets displaced when a plant goes down, and gate fees follow scarcity. Producing less residual waste is the only hedge.
That is not a slogan. Every tonne pulled out of residual by separating food, card, plastics, metal and glass under the business recycling rules is a tonne that does not need a plant with spare capacity.
Where a sorted load fits
Our loads are sorted at the transfer station and more than 80% of what we collect is diverted before anything reaches an energy-from-waste gate. The residual fraction we send for treatment is small, which is the point: a firm that tips mixed loads is a firm whose costs and reliability depend on capacity it does not control.
For trade customers that is our commercial waste collection service on a schedule, and industrial waste removal for bulk clear-outs. The wider figures on where Scotland's waste goes are in where does Scotland's rubbish go now?.
The review's own conclusion is the one we would have written: improved waste reduction and recycling are essential for closing the capacity gap and strengthening resilience. The plants are for what is left, not for what could have been recycled.
