The Turnbull government has “no plans” to change the Renewable Energy Target, environment minister Josh Frydenberg has said in response to reports conservative Coalition MPs want the target dropped.

In an interview on Radio National Frydenberg said the RET was “balanced” but “not cost free” – warning it added $63 a year to household power bills and attacking Labor for its 50% target on renewables.

On Monday, deputy prime minister Barnaby Joyce refused to commit the government to maintaining the RET. Tony Abbott and South Australian senator Cory Bernardi have both publicly argued that renewable energy targets should be scrapped.

On Tuesday, Frydenberg said the government had “no plans” to change the target of 33,000 gigawatt hours of energy from renewable energy by 2020, or about 23.5%. He said it was a challenge to meet the target, but a balanced one.

Frydenberg said the Australian Energy Market Commission had estimated the RET cost households $63 a year, but that was a “far cry from the 50% target that Bill Shorten is proposing, which we do know will increase prices”.

Asked about the Warburton review, which found removing the RET would push up electricity prices, Frydenberg said that was “not right” and a “myth put forward by Labor”. He said the review had found that increasing use of renewables “pushes out” coal, adding to power costs in the medium and long term.

Frydenberg said part of the reason for South Australia’s increase in electricity prices was its uptake of renewables and taking the Northern power plant offline.

The environment minister said Australia should take a technology neutral approach to meet its emissions reduction targets. He said ultra-supercritical coal power plants could produce 700kg of CO2 for each megawatt hour of electricity, compared with Australia’s current average of 820kg.

Frydenberg did not directly respond to questions about how ultra-supercritical power stations would be funded, nor whether they were incompatible with long term targets of zero emissions. He said all choices to reduce emissions had a cost, and more efficient coal plants could reduce emissions from electricity production by 40%.

Frydenberg recommitted Australia to its Paris target to reduce emissions to 26-28% on 2005 levels by 2030, even if Donald Trump pulled the United States out of the international climate agreement.

Frydenberg continued to emphasise that stability of the power system was the government’s main objective. He warned that integration of renewable energy into the grid was “very challenging” because renewable sources were more intermittent than centralised, synchronous generation from coal and gas.

On Monday Labor and the Greens warned the push from Coalition conservatives to cut the RET showed the party was determined to follow Trump’s lead, and was harming jobs in the renewable energy sector.

In a statement, the Electrical Trades Union national policy officer, Lance McCallum, warned the government not to present renewables as “unstable, expensive and risky”.

He cited a US report, released in January, that a renewable energy target in that country would create at least 4.7m jobs, reduce prices or increase them by at most one cent per kilowatt hour.

“The evidence shows very clearly that RETs are economically positive, environmentally beneficial, deliver valuable health savings, and are a vital step on the path we must walk to a clean energy future,” McCallum said.