Treasurer Scott Morrison and Energy Minister Josh Frydenberg revealed on Tuesday the Commonwealth was discussions with the NSW and Victorian governments to buy some or all of their stakes to add to its own.
The budget papers call this an "exciting idea" that comes as a study is underway into the scheme's likely expansion, which Prime Minister Malcolm Turnbull has dubbed Snowy 2.0.
But there's no money set aside for any buyback.
The biggest ticket item in the 2017/18 federal budget is $110 million to help build a solar thermal plant in Port Augusta, South Australia.
The government indicated in the 2016 federal election it was likely to help fund the project and confirmed this as part of a deal with key crossbench senator Nick Xenophon over company tax cut legislation.
It will also give the South Australian government $36.6 million over two years to invest in other energy infrastructure, with the money coming from an asset recycling deal.
Amid intense political focus on a looming gas shortage, the budget contains $86 million in measures to sure up the domestic gas market.
There's $30 million for scientific assessments at three sites - yet to be decided - of the impact on water supplies of possible new unconventional gas developments.
Another $28.7 million will be spent to accelerate "responsible development" of onshore gas sources for the domestic market and nearly $20 million on a Gas Market Reform Group to improve transparency in the sector.
The government will also fund studies on the prospect of two new gas pipelines - one from WA and one from the NT to Moomba in north-eastern SA - the constraints on increasing gas supply on the east coast, and potential offshore gas production in SA.
Competition watchdog the ACCC will get $6.6 million over three years to monitor gas market plus $7.9 million in 2017/18 to review electricity retail prices.
