NSW Energy Minister Penny Sharpe has dismissed reports that keeping Eraring Power Station open could cost $3 billion for two years, but she declined to offer an alternative figure regarding the cost of keeping it open beyond mid-2025.
She slammed her predecessor Matt Kean for releasing the $3billion figure, which said was unverified.
"That ($3 billion) is not the information that I have received over the weekend and I have asked," Ms Sharpe said on Monday.
Mr Kean claimed the figure was based on departmental briefings given to the former Coalition government.
The government is on the cusp of announcing whether it will intervene to keep the Lake Macquarie coal generator going in order to provide grid stability throughout the clean energy transition.
It is likely the O'Reilly Report, which recommends keeping Eraring open, will be an influential factor in the decision.
Ms Sharpe insisted that a decision about the future of Eraring, which supplies about 25 per cent of the state's energy needs, had not been made.
"We are looking at all options when it comes to Eraring," she said.
"We're looking at all of the alternatives around renewable energy transmission and storage and we're also having the discussions about how we will work through any early retirement of coal-fired power.
"There is a long way to go in this."
She said maintaining energy stability would take priority over the cost to taxpayers.
"We haven't looked at the figures in terms of how much it might cost," she said.
"We are working very carefully to do three things - Keep the lights on, keep price pressure on prices for households and businesses as low as possible, and get renewable energy storage and transmission done by 2030."
Ms Sharpe confirmed the Waratah Battery, which is being built on the site of the former Munmorah Power Station, was on track.
The 850 megawatt battery is designed to act as a 'shock absorber' in the event of power surges caused by bushfires and lightning strikes.
Akaysha Energy is responsible for the construction and operation of the battery. It is due to be completed in 2025, before the earliest possible closure of the Eraring Power Station in August 2025.
Ms Sharpe echoed the criticism of Premier Chris Minns last Friday regarding the sale of Eraring Power Station for $50million in 2013 by the former Coalition government.
"What we inherited when we came to government was a roadmap that was over budget and had delays built into it," she said.
"But what we also inherited was a privatised electricity system. The previous government sold five power stations and three distribution networks in just four years.
"The selling off of our electricity system has made every aspect of this transition part of the job more difficult."
Premier Chris Minns also dismissed the sum and questioned the opposition MP's contribution to the energy-transition debate.
"I don't know where he got those numbers from," he said.
"Matt Kean's intervention is completely cynical.
"He's responsible for the fact that renewable energy production is delayed in NSW, it's over budget and he didn't tell anyone before the last election.
"We've been left with a bonfire, effectively, when it comes to energy costs in NSW."
Mr Minns said the Labor government remained committed to the shift to renewable energy and was aiming to get that transition back on track.
Electricity market operator AEMO last month warned NSW could face energy reliability shortfalls from 2025 after the retirement of Eraring, noting that risk had increased due to higher demand forecasts among other factors.
Environmentalists oppose keeping open the plant, which is Australia's largest greenhouse gas emitter, and say such a move would be a retrograde step in the shift to renewable power.
Mr Kean has been contacted for comment.
