Environment Minister Simon Corbell announced a grants program to companies offering battery storage for households and businesses with rooftop solar, beginning next year, in what he said was the largest rollout of battery storage of any city in the country.

The $20 million program will subsidise 36MW of battery storage, allowing people with rooftop solar to store energy to use at night or at other times of low solar generation, and will allow them also to sell power back into the grid.

Mr Corbell also announced a fourth renewables auction on Friday, this time for 109 MW of capacity, an auction likely to result in the funding of more wind farms but also open to solar.

Mr Corbell said the battery package was not targeted at the more than 10,000 households receiving the premium feed-in tariff, in a scheme that was closed to newcomers in 2011, because the amount they already made from feeding energy into the grid would outweigh the benefits of storing it.

But half of all rooftop panels were installed without a higher feed-in tariff.

"For those households there is a very significant opportunity because battery storage allows them firstly to reduce their electricity costs further, but secondly it allow them to sell any surplus that they store and don't need themselves back into the grid," he said.

In opting for the battery storage scheme, the government has rejected an earlier idea of "big-dish" or other large-scale solar. Mr Corbell said the storage scheme was more cost effective and would bring more benefits to the territory, including making Canberra a centre of battery storage technology, than a big dish installed "somewhere probably in NSW, Victoria or South Australia".

"There are a number of Canberra companies that are positioning themselves to take advantage of this significant technological revolution that is coming forward when it comes to battery storage at the household and business level," he said.

"... Battery storage is going to fundamentally change the way our electricity networks operate. We want the ACT to be at the forefront of that change to take advantage of the economic opportunity that comes from this massive increase in this side of the low carbon economy."

In a pilot program next year, $600,000 in grants would be given to companies contracted to deliver battery storage to households, allowing them to offer competitive packages to households.

The pilot would test "regulatory and technical issues".

"This is a new technology and we need to make sure that our electrical safety laws, our other planning and development laws, are keeping pace with the arrival of this technology and making sure we're well positioned for a larger scale rollout," Mr Corbell said.

After the pilot, the program would be rolled out to more than 5000 homes from 2017 to 2020.

Companies winning a large-scale feed-in tariff in the 2016 auction would be required to contribute funding which would help pay for the battery storage scheme.

The decision to opt for battery storage comes after the government called an expressions of interest in next generation renewables with storage earlier this year. Mr Corbell said the options included big dish solar, thermal solar, pumped hydro with solar and other options.

Mr Corbell rejected the suggestion that it would subside solar power for wealthy households, saying some of the largest uptake of rooftop solar was in suburbs of lower incomes.