One of Australia’s largest rooftop solar installations has hit a new milestone – generating a whopping 312 kilowatts of power.

The 948 solar panels on the Broadway Fair shopping complex in Perth's western suburbs – the largest rooftop setup in WA - now generates a third of the centre’s power.

Broadway Fair general manager Paul Avon-Smith says it cuts about $20,000 a month off power bills, which can be redirected to other capital works.

“We were looking for soft approach for the cost of doing capital works,” Mr Avon-Smith told the ABC.

“It gives us an alternative to help cushion rent increases and price rises for our tenant base in a pretty tough market, but allows us to finance crucial capital works.

“So that allowed us to do a roof replacement project, plus put the solar in, with there being no upward pressure on our rents for tenants.”

Infinite Energy set up the $600,000 system.

Infinite managing director Aidan Jenkins says that as the cost of solar panels continues to plummet, the business model for commercial-sized installations gets better and better.

“Solar currently represents the cheapest way to generate electricity, so we will start to see these type of systems become the norm over the next couple of years,” he said.

WA Energy Minister Mike Nahan has welcomed what he describes as a coming “tsunami” of commercial solar installations.

“It just adds more generating capacity to an already oversupplied system, but it is something we have to cope with,” Mr Nahan said.

“Over the next decade these are going to crowd out traditional, large-scale generation of coal and gas.

“As we go down the track, these technologies on businesses and households illustrates that into the future we are going to have to reduce our production of traditional energy sources and that's the challenge.”