"There was a significant fall in battery prices mid-way through 2016 and the popularity of batteries just exploded," he told the ABC.
He said with South Australia battling blackouts, batteries would eventually be a "game changer" for Australia's energy networks.
Solar batteries are expensive, but intense competition has brought prices down.
About 20 manufacturers are producing around 90 products for sale in Australia, with the cheapest battery retailing for $1,200.
Many larger batteries still cost between $8,000 and $10,000.
Mr Johnston said batteries held benefits for the entire community, not just homeowners.
He said there was potential for the energy stored in batteries to be put back into the grid for the public to use.
"I'd say three years is when we'd start to see that batteries are playing an important role in the network," Mr Johnston said.
"It's both something that needs to be managed but also something that can present a great opportunity for Australia."
Source - ABC onlineWritten by consumer affairs reporter Amy Bainbridge and the National Reporting Team's Rebecca Armitage