Biogas from wasted oat husks a world-first fix for electricity at Blue Lake Milling in South Australia's Bordertown
Biogass Renewables project manager Ross Merchant and Blue Lake Milling commercial projects manager Jeremy Neale at the Bordertown mill's $8.1 million biogas plant that took husks (bottom right) from its oat hulling (left) and used gas from them as bioenergy.
Images courtesy Blue Lake Milling
In a world-first, cereal oat supplier Blue Lake Milling at Bordertown in South Australia in 2021 started generating its own electricity from the biogas of oat husks.
Blue Lake Milling spent $8.1 million on a biogas plant to use the 24,000 tonnes of oat husks it processed each year and were previously sold as stock feed, used as packing material or thrown away. The biogas plant converted all the mill's oat husks into bioenergy through anaerobic digestion: microorganisms breaking down biodegradable material into mush. This gave off a mix of methane gas and carbon dioxide that fuelled an onsite generator to produce electricity and heat to power the oat mill.
Blue Lakes Milling commercial projects manager Jeremy Neale said power reliability first sparked the plant’s need for an alternate source more than a decade ago. Besides the electricity factor limiting its expansion, the mill was hit by a lot of brownouts by being at the end of a power line. Generating its own power eased those risks for Blue Lakes Milling. Set up in the 1980s, Blue Lakes Milling employed 120 people at Bordertown, in a town of less than 3000.
As a 24-hour five-day-a-week operation, the mill’s previously monthly energy bill was about $80,000. The bioenergy plant would cut that expense and generate enough power for the mill with a third more put back into the power grid.
In 2017, Blue Lake Milling received a $25,000 grant for an energy efficiency study of its operations and ways to reduce power. Its bioenergy plant proposal got another $20,000 from the state government for a full feasibility study in 2018 and $2.5 million from the government in 2019 towards construction. Biogass Renewables was contracted for the plant design and to operate and maintain it.
While common in Europe, the anaerobic digestion plant was just one of five in Australia, mostly fed by assorted food waste. Blue Lake Milling’s ambitious plan to use only oat husks was met with scepticism.“They all told us we were crazy,” according to Neale, who spent two weeks at a workshop in Germany that had more than 15,000 bioenergy plants.
Blue Lake Milling also was drawn to the idea of a biogas plant’s value as a “renewable and clean” energy source. It also moved from gas-powered forklifts to electric models and explored other opportunities to reduce its waste impact. CBH, parent company of Blue Lake Milling, used its bioenergy plant to gauge the potential for similar systems at its other grain operations around Australia.
Neale said pioneering such its large project had complications such as the year-long wait for EPA (Environment Protection Agency) approval because there were no legal procedures in place for it.
