The Turnbull government has bought another 45m tonnes of carbon abatement for $557m, but analysts say its Direct Action policy cannot reduce Australia’s greenhouse emissions or meet the promised long-term targets.

The government has now spent almost half its $2.55bn emissions reduction fund to buy less than half of the greenhouse reductions needed to meet its 2020 target.

At its first auction, held in April, the government bought 47m tonnes of abatement for $660m – an average price of $13.50 a tonne. Across the two auctions it has bought 92m tonnes of abatement for an average price of $13.12 a tonne.

But analysts say that while the auctions have been successful, emissions will still rise and the overall Direct Action policy will not reduce Australia’s emissions to meet its long-term, internationally promised reduction target for 2030.

“While the ERF has again been successful in contracting abatement, the policy has not curbed Australia’s net emissions growth. Accounting for the ERF, we continue to forecast a 15% increase in national emissions through to 2030,” said Hugh Grossman, the chief executive director of the Reputex analytical firm.

John Connor, chief executive of the Climate Institute, said the emissions reduction fund was only ever a sidebar policy and could not meet long-term greenhouse goals.

“The government has run another professional auction process, but now we need to get down to the policies that matter. We need to tackle the biggest polluting sector of the economy – the electricity sector. This starts with a closure plan for our old and inefficient coal-fired power plants so they can be replaced with clean energy alternatives.

“The key point remains – the ERF is a supporting policy,” Connor said.

A proportion of the greenhouse reductions bought will be delivered after 2020, the date by which the government has promised to reduce emissions by 5% compared with 2000 levels. They will count towards the longer-term 2030 target the government will pledge at the United Nations conference beginning in Paris in December.

Chloe Munro, the chair of the Clean Energy Regulator, which runs the auctions, said she was “pleased with the high level of participation and competitive bidding which has allowed us to source significant abatement at a lower average price than the first auction”.

She said the CER had awarded 129 carbon abatement contracts, ranging from one to 10 years in length, including industrial and mining projects for the first time.

Questions have been raised about whether all the emission reductions bought were “additional”, ie would not have happened without the government money, and thinktanks have pointed out that the fund can only achieve a tiny proportion of Australia’s promised longer-term greenhouse gas reductions.

But the environment minister, Greg Hunt, said the ERF was an international success.

“I look forward to highlighting the success of the fund when I return to the Paris climate change talks and outline Australia’s strong suite of policies to reduce emissions,” he said in a statement.

“The results today are further proof that we have one of the most effective systems in the world for significantly reducing emissions.”

Labor’s environment spokesman Mark Butler said Australians weren’t getting “value for money” from a policy that had no hope of reaching Australia’s long-term goals.

Greens spokesperson Senator Larissa Waters compared the emission reductions bought with the greenhouse gas that would be created from burning coal from Adani’s proposed $16bn Carmichael mine.

“The government has just given half a billion dollars of taxpayers’ money to big polluters to achieve pollution reduction of just 1% of the expected emissions of Adani’s Carmichael coalmine,” she said.

On current projections the government needs 236m tonnes of abatement to meet the 2020 goal, but Hunt has said that figure is likely to be revised downwards and the government is also likely to receive for free up to 16m tonnes of abatement in the form of international permits from landfill operators who ended up with a windfall gain after the abolition of the emissions trading scheme.

The first auction bought emission reductions mainly by paying for the continuation of projects conducted under the former government’s carbon farming initiative from farmers who promised not to clear land, and landfill operators that collect and flare, or use, methane.

Land-use projects also dominated the second auction, but it also bought emission reduction from savannah burning projects, and a small number of industry projects, from companies like Wesfarmers, Energy Australia and Adelaide Brighton Cement.

Reputex predicts the ERF money will be exhausted by the end of 2016, after one or two more auctions next year. And it predicts that without significant changes to other aspects of the Direct Action policy, Australia’s emissions will rise by 2030, not decline by between 26 and 28%, as Australia will promise at the United Nations meeting in Paris.