Premier Daniel Andrews and Energy Minister Lily D'Ambrosio on Tuesday announced six successful projects which are expected to deliver power to more than 646,000 homes once complete.

"It's a fact that the quickest new build of energy, the cheapest new build of energy that you can get into the system, is renewable energy," Ms D'Ambrosio told reporters.

The government ran a reverse auctions scheme which saw project developers compete to be the lowest-cost provider.

Mr Andrews called it a "stunning success" and Ms D'Ambrosio said it provided the certainties investors needed.

Berrybank wind farm west of Geelong, will produce 180MW; Cawarp solar farm south of Mildura will produce 121.6MW; Cohuna solar farm north-west of Echuca will produce 34.2MW; Dundonnell wind farm north-east of Warrnambool will produce 336MW; Mortlake South wind farm will produce 157.5MW; and Winton solar farm near Benalla will produce 98.8MW.

Building will start early 2019 and they are expected to be completed in 2020.

The state government has renewable energy targets of 25 per cent of generation by 2020 and 40 per cent of electricity generation by 2025.

Mr Andrews on Tuesday also announced if re-elected, 10,000 households which already have solar panels could be paid nearly $5000 to install battery units, part of a wider, $1.3 billion solar energy plan which also includes subsidies for solar panels and hot water systems.

Opposition Leader Matthew Guy said more details on the renewable energy reverse auction needed to be released to make sure taxpayers weren't paying more for the scheme than they needed to.

"I don't think we should be subsidising power generation simply for the sake of it," he told reporters.

Australian Associated Press