Data from the Climate Change Department yesterday shows the power generation sector accounted for about 170 million tonnes of carbon dioxide emissions in the 2010-11 financial year, which could mean a carbon tax bill of $3.9bn if repeated next year.
The Weekend Australian reported this month that InterGen - the operator of Queensland's black-coal power generator Millmerran - sought help from the federal government's Energy Security Council for loan support because the looming carbon tax had hit its $467 million refinancing.
Victoria's largest power plant, Loy Yang Power, has also had talks with the ESC as it has a $565m refinancing due in November.
The latest greenhouse emissions figures show the nation's top five carbon dioxide emitters in 2010-11 were all coal-fired power generators. But as the government assembled the carbon pricing package, emissions from the sector fell about six million tonnes over the previous 12 months.
The two NSW state-owned generators - Macquarie Generation and Delta Electricity - were the two biggest emitters in 2010-11, with 20.3 million tonnes and 19.8 million tonnes in CO2 emissions respectively.
If the same emissions levels were repeated next year, Macquarie would face a carbon tax bill of more than $466m and Delta would pay $455m, based on the government's starting carbon price of $23 a tonne from July.
The companies told The Australian yesterday they would try to recoup the cost through higher electricity prices, but because prices are set by bids in the national electricity market, they are uncertain how much they will be able to recover.
The government warns that the National Greenhouse and Energy Reporting figures, released yesterday, may not be an accurate guide to next year's carbon tax liability. This is because the reporting is for holding companies, and some of their emissions may not be subject to the carbon tax.
But The Australian confirmed with several of the big power companies that their reported NGER figures broadly represent emissions they would be liable for under the carbon tax.
The chief executive of the Electricity Supply Association of Australia, Matthew Warren, said some companies might have to pay hundreds of millions of dollars for permits in advance of when the electricity was generated and sold.
Mr Warren said the Investor Reference Group estimated that electricity generators would need to hold positions on $6bn worth of forward permits to maintain current levels of electricity contracts.
But a spokesman for Climate Change Minister Greg Combet said the government had announced it would make loans available to generators for the forward purchasing of carbon permits. This was in addition to $5.5bn in assistance for the emissions-intensive generators.
The mid-year budget update had shown the carbon price would raise $7.7bn in 2012-13, Mr Combet's spokesman said.
"Electricity generation is one of the most pollution-intensive sectors of our economy," he said.
"It is essential Australia begins to transform this sector so our economy remains competitive as the world moves to tackle climate change by reducing carbon emissions."
The government will put more than $4bn into household assistance this year to offset higher prices caused by the carbon tax.
Mr Combet's spokesman said there was substantial assistance for industry through the Jobs and Competitiveness Program, and for households through tax cuts, higher family payments and pension increases.
But Mr Warren said: "Without deferred settlement arrangements, allowing energy companies to pay for permits when they sell the energy and produce the emissions, they will need new lines of credit to finance their upfront purchase of forward vintages."
The opposition yesterday attacked the government over Virgin Australia's decision to introduce a carbon tax surcharge.
But Mr Combet's spokesman said Virgin had made the announcement on July 11 last year.
