Households are dumping expensive green power deals as electricity costs go through the roof.
Almost 140,000 homes nationwide abandoned the contracts in the past year.
The backlash comes as new research suggests some retailers are overcharging for green power arrangements.
A study by energy comparison site switchwise.com.au reveals an average home can pay up to $245 more for a full green power plan, depending on the chosen green supplier.
“Some customers are definitely paying too much and are being exploited,” Switchwise founder Shaun Johnson said.
Under the deals, consumers typically agree to pay $150 to $400 a year more for electricity in exchange for companies buying back the same amount of consumption from renewable sources such as wind and solar power.
The renewable energy is then fed into the national grid in a bid to reduce greenhouse gas emissions.
Customers on GreenPower are still mostly supplied with coal-fired electricity.
Data from the National GreenPower Accreditation Program reveals the number of households subscribed to the scheme shrunk 15 per cent to 802,619 in the past year.
Victoria has the nation’s biggest number of GreenPower customers at almost 280,000, or 12 per cent of households, despite a loss of 71,000 in the past year.
Mr Johnson said many opted out of the plans after the collapse of retailer Jackgreen last November.
“Consumers appear to be less willing to pay a premium after seeing their power bills rise by over 20 per cent in the last two years,” he said.
“As green as you want to be, people also want to save money.”
Mr Johnson said consumers who shopped around could still get competitive GreenPower deals.
The drop in support would make it harder for the Federal Government to reach its goal of 20 per cent of renewable energy generation by 2020, he said.