Households paid for spare solar with beer

An Australian beer giant plans to help power its operations with extra energy from household rooftop solar systems - and will pay home owners with liquid gold.

Carlton and United Breweries says its new "solar exchange" program will let households exchange $30 worth of extra solar credit on their power bill for a slab of VB, which the brewery will deliver quarterly.

"We believe the average customer will get a slab a month," Brian Phan from CUB told AAP.

He said the company's Victoria Bitter was already brewed using offset solar power, and the extra rooftop solar would be used to power the company's head office, and to produce its other beers.

The company has allowed for 500 households to join the program, and the beer payments will be limited to 30 slabs a year.

The program is open to households in Queensland, NSW, Victoria and South Australia.

More than two million, or 21 per cent, of Australian households have rooftop solar, but many only produce just enough energy for home use.

CUB is using the energy technology company Power Ledger to facilitate the solar power transactions, which will rely on blockchain technology.

"Beer companies around the world are starting to place greater emphasis on renewables," Dr Gemma Green from Power Ledger told AAP.

She says blockchain can enable hundreds of secure transactions every second, which allows energy trades from thousands of different sources - in this case, households.

"Using Power Ledger, households are providing solar to Carlton, and they are being paid for that energy in beer," she said.

Last year, CUB began powering its operations with offset solar, from Victoria's Karadoc solar farm.

It also installed solar panels on the roof of the Abbotsford Brewery in Melbourne, and Yatala Brewery in Queensland.