Blantyre Farms at Young, 375 kilometres south-west of Sydney, burns the nasty methane that used to go into the atmosphere to generate all its electricity needs.

"The biggest winner of all of it is that we no longer have a power bill and we can even sell what we don't use back into the grid," Blantyre co-owner Edwina Beveridge said Thursday.

The manure from 22,000 pigs that used to go into landfill is now piped to a covered pond the size of two Olympic swimming pools.

Methane, a greenhouse gas 23 times more polluting than carbon dioxide, is piped back and generates electricity and also heats the water pipes that keep the stalls warm in winter.

The Beveridge family, who stand to make hundreds of thousands of dollars from supplying credits to big polluters in a scheme that is linked to Europe's, are sharing their good fortune with those helping generate it.

"We reward them every day," Beveridge said. "They love chocolate ice cream, just like my kids."

Leftover ice cream, along with yogurt, is brought in by tanker from Sydney.