Noxious weed prickly acacia to be turned into ‘green coal’ by renewable energy company in outback Queensland

One of the most noxious weeds in Australia will soon be used to make a ‘green’ alternative to coal.

Prickly acacia, originally from Africa, has been a multi-million-dollar problem across outback Queensland for decades, infesting prime grazing land, killing native grasslands and degrading soil health. 

But after a decade of research, one company has discovered how to turn the small, thorny shrub into a carbon neutral energy source that will be used in cogeneration power plants. 

Green Day Energy will build a $30 million plant in the north-west Queensland town of Richmond, where prickly acacia has been out of control since the 1990s. 

Silver bullet to weed problem 

The prickly acacia will be harvested, made into wood chips, then roasted to become a fuel source like thermal coal. 

Biochar is another material made from prickly acacia that can be used to create green hydrogen.

It can also be added to soil to improve its health and quality, and can sell for up to $2,000 a tonne – while coal sells for around $400 a tonne. 

Green Day Energy founder Brad Carswell said the $30 million project was a game-changer when it came to tackling the invasive weed. 

“I think it’s been looked at [before] but not in the way we’ve been looking at it,” Mr Carswell said. 

“We’ve always said you need an economic solution to prickly acacia, [or] its never going to be touched.

“We have a very high skilled team and have been coming to Richmond for the past 10 years.”

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Job creation 

Richmond Shire Council Mayor John Wharton said the region had been trying to harvest prickly acacia for as long as he could remember. 

“When I was a young fella we used to poison them, but we’ve come a long way since then,” Mr Wharton said. 

“We think it’s great, there will be a lot of jobs in the process and landholders will be able to do it themselves too.”

The plant is expected to be running in six months.