The scientists found that anaerobic digestion of waste bananas, skins and stalks could produce gas that could be made into a commercially viable fuel.
“It’s not far-fetched and it’s not rocket science. The fuel comes from gas from bananas and the technology is already out there,” council chief executive Tony Heidrich told EnergyReview.net.
Research into power co-generation from banana waste, financed as part of Queensland’s Sustainable Energy Innovation Fund, was partially backed by state utility Ergon Energy since 2001.
The utility wanted to know if it could generate electricity from the gas produced by the process.
But bananas were found to be six times less efficient to produce power compared to coal-fired power stations and Ergon withdrew its support after the first stage.
However, the research did find that a plant conducting anaerobic digestion of 6000 tonnes of banana waste a year would produce the energy equivalent to 222,000 litres of diesel, Heidrich said.
EnergyReview.net understands the gas from the process requires compression and scrubbing before it is turned into a fuel replacement.
Between 10% to 20% of the 2000 council members’ annual banana crop of 315,000 tonnes is waste.
This would provide an available supply of stalks and unwanted fruit to the gas-producing bacteria of 30,000 to 60,000 tonnes, Heidrich said.
To test production of the fuel on a farm, the council has applied for state and federal government funding of A$550,000 for a shipping container-sized plant to be run for 12 to 18 months and digesting about 25 tonnes of waste.
While the plant could be developed to provide fuel for one banana grower, or as a power generator for a remote community, a larger version would be useful for a collective of growers, according to Heidrich.
“My vision for it would be a larger facility in the middle of [a group of] growers and have big vats digesting it, capturing the gas and on-selling the fuel.”
Banana diesel would also not require the expensive facilities required to produce ethanol as a by-product of sugarcane growing, Heidrich said.
As an added bonus, the waste-to-energy conversion also produced residues that could be used as organic fertilisers, he said.
