(CNN)When Australia's coronavirus lockdown forced bars and restaurants to shut down in March, breweries were left with huge inventories of unsold, stale beer.
But instead of going to waste, some expired ales and lagers in the state of South Australia have been serving a new purpose: powering a water treatment plant.
At the Glenelg Wastewater Treatment Plant to the west of the state capital Adelaide, millions of liters of unused beer from local breweries have been converted into renewable energy to power its water treatment process in recent months.
The plant mixes organic industrial waste with sewage sludge to produce biogas, which is then turned into electricity to power the whole facility. It usually generates enough biogas to provide about 80% of its energy needs.
But the recent influx of beer has boosted its energy generation to new levels, reaching 654 megawatt hours in a single month, Lisa Hannant, senior manager of production and treatment at SA Water, said in a statement.
"By adding around 150,000 litres of expired beer per week, we generated a record 355,200 cubic meters of biogas in May and another 320,000 cubic metres in June, which is enough to power 1,200 houses," Hannant said.