Lorna Slater has been accused of having not “thought things through” after admitting the Scottish Government is yet to assess using waste to create sustainable aviation fuel (SAF).

The Scottish Government has committed to ban waste being sent to landfill by 2025 as part of its climate strategy.

But concerns have been raised that SNP and Greens ministers have not planned for some of Scotland’s “unavoidable, unrecyclable residual waste” being used to produce sustainable fuels and chemicals.

The Scottish Conservatives have called for the Scottish Government to explore using any remaining waste for SAF as part of efforts to clean up air travel.

But critics have warned that SAF is still being developed and may not be ready until the 2030s or even later.

The call comes after Ms Slater, the Scottish Government’s Circular Economy Minister, admitted that she has not “assessed the impacts” on how much waste can be harnessed after it is reduced and separated “specifically for the production” of SAF as well as other chemicals.

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The Scottish Government said it was “now considering actions” for its sustainable aviation strategy.

A key report published last year into the Scottish Government’s aim to end incineration of waste concluded that “properly regulated incineration has an important role to play…in managing Scotland’s unavoidable, unrecyclable residual waste in a sanitary manner”.

It added: “The demand for this capacity is currently growing, so the supply is rightly planned to grow too. However, the planned supply will, in all scenarios modelled, be more than Scotland will need in four to five years’ time to at least 2050.”

In 2021, ahead of COP26, the UK Government shortlisted eight companies to share £15 million to support the development of "first-of-a-kind production plants turning waste into sustainable aviation fuel".

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Then transport secretary Grant Shapps said that SAF would be produced across the UK with the potential to create more than 1,000 green jobs across the UK.

The projects shortlisted included using everyday household and commercial back bag rubbish, one using sewage and another harnessing alcohol derived from wastes, including flue gases from industry.

A Transport Scotland consultation ahead of the Scottish Government’s aviation strategy revealed “a desire to encourage production of SAF in Scotland”.

It added: “This included actively working to establish manufacturing sites at suitable locations such as Aberdeenshire, Grangemouth and possibly even in Shetland using the existing pipelines to get SAF to the mainland.

“Several respondents said that SAF was currently cost-prohibitive and that a key priority would be reducing production costs, including by encouraging domestic production within Scotland.”

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Ms Slater said: “The Scottish Government has not assessed the impacts of source reduction and separation on the availability of residual waste, specifically for the production of SAF, and other fuels, oil and chemicals.

“However, it is considering potential actions it could take on Sustainable Aviation Fuel (SAF) as it develops its aviation strategy.”

She added: “The independent review of incineration assessed what residual waste capacity Scotland needs to manage Scotland’s unavoidable, unrecyclable residual waste.

“It modelled several scenarios, including the impact of meeting Scotland’s waste reduction and recycling targets, and concluded that, if all energy from waste facilities in the development pipeline are built to schedule, there is a risk of long-term overcapacity beginning from 2026 or 2027.”

The Conservatives have warned that the Scottish Government has not evaluated how the new and reducing market for black bin waste will be served – with supply decreasing as more waste is recycled.

It is feared that with demand increasing, so could the price.

That could result in the market being incentivised to increase supply of waste, which would fly in the face of the Scottish Government’s strategy to reduce non-recyclable rubbish.

Scottish Conservative circular economy spokesperson, Maurice Golden, said: “As ever when it comes to environmental issues, the Scottish Government hasn’t planned, hasn’t thought things through, and isn’t on top of the detail.

“While we want to keep black bin waste as low as possible, it does still have some useful functions.

“That’s why it needs to be used as high-value as possible.

“Putting this towards sustainable aviation fuel, and other chemical uses, would be far more beneficial than simply burning it.

“The Scottish Government should know all this, but has once again been found wanting on issues of waste and energy.”

A Scottish Government spokesperson said: “Reducing the amount of black bin waste we produce by recycling and re-using more is a good thing, and it’s a critical part of what we need to do to tackle the climate crisis.

“The Scottish Government published a report from the independent review of incineration just last year, that assessed how much residual waste capacity Scotland needs to manage Scotland’s unavoidable, unrecyclable residual waste.

“We are now considering actions we could take on Sustainable Aviation Fuel (SAF) as we develop our aviation strategy.”