Former prime minister Malcolm Turnbull’s vision for the Snowy 2.0 pumped hydro scheme to power Australia’s renewable energy future looks like coming at a huge cost.

Although a 2000-page environmental impact assessment released last week has given a green light to the largest electricity infrastructure project ever undertaken, expert objections to its cost in financial and environmental terms are alarming.

“Initially promised at $2 billion, it was quickly revised to $4 billion and a contract for part of its construction has been agreed at $5.1 billion,” said Dr Bruce Mountain, director of the Victoria Energy Policy Centre.

And the New South Wales National Parks Association executive officer Gary Dunnett said in a statement that Kosciuszko National Park would be partially destroyed.

Twenty square kilometres of largely undisturbed native alpine bush would be affected, with nine million cubic metres of excavated rock spoil to be dumped throughout the park including in existing reservoirs, reducing their active storage capacities and stream flows.

But the most disturbing critique has come through Dr Mountain’s analysis of the business case for Snowy 2.0 and its cost to taxpayers.

When completed, Snowy 2.0 would not have a monopoly in Australia’s national electricity market.

“There has been no credible market assessment and this alone represents an unjustified risk,” Dr Mountain told The New Daily.

His centre is undertaking a market impact study.

The NSW NPA has said that a price tag of $10 billion for Snowy 2.0 now looks more likely when the cost of massive transmission upgrades and ongoing transmission operating costs to connect its new underground pumped hydropower station to the national grid is taken into account.

All of this capital and operating expenditure would buy a facility with 2000MW of production able to transmit to the national grid over several days if fully charged.