* Manufacturers turn to sunny Australia as testing ground
* Tesla, Samsung, Panasonic, Enphase take on local products
* Interest in batteries seen soaring as prices fall
* Already 15 pct of Australian households have solar panels
By Melanie Burton and Byron Kaye
MELBOURNE/SYDNEY, June 3 When Frances Miao put solar panels on the rooftop of her three-storey home in the Sydney suburb of Hunters Hill, the emergency doctor planned to wait five years before spending more on battery storage.
But with payments falling for feeding any unused energy back into the power grid, Miao decided to double down on her investment with a battery so she can use more of the electricity she generates.
Energy giants such as Panasonic, Tesla and Samsung SDI are targetting Australia as a test ground for battery storage, betting that more consumers in the country with the world's highest rate of rooftop solar panels will rush to batteries as prices fall from current levels around A$10,000 ($7,200) for an average home.
"(Australia) has very high residential solar penetration, plenty of sunshine, relatively high energy prices and ... governments are not subsidising to the extent they used to," said Panasonic Australia Managing Director Paul Reid.
"It creates an environment that we think is very much conducive to the take-up of battery storage, perhaps more than any other country in the world right now."
Solar is expected to become the leading source of renewable power by 2040, according to the International Energy Association (IEA). By 2050, it is expected to account for about half of the global renewables market, or 16 percent of total global energy supply. This would be split evenly between rooftops and industrial scale parks.
Australia is seen as an ideal opportunity, with around 1.5 million, or 15 percent, of households already equipped with rooftop solar.
Morgan Stanley estimated in a 2015 report that battery installations in Australia could soar to a million by 2020. Industry sources estimate there are less than 1,000 modern battery systems currently in place.
U.S. firm Enphase Energy, which is using Australia for the global launch of its new battery storage system, says demand has eclipsed its expectations and is targetting sales of 60,000 units in 2016/17.
"In the next 12-months we'll see some modest growth," said the company's Asia-Pacific head Nathan Dunn. "After the next 24 months you'll start to see that explosive growth happen."
Growth hopes are being spurred by expectations that battery prices will fall as mass take-up begins. Australian energy retailer AGL expects costs to fall by 60 per cent over the next five years as materials performance and chemical technology improve.
Tesla launched in Australia in December. The firm, which has already announced plans for a second generation lithium battery, would build on its lessons from the Australian market, spokesman Heath Walker said.
Panasonic also hopes to support deployment of batteries in other markets.
"The three primary objectives are, to test the product in Australian homes, to develop new business models, to develop next generation batteries," said Managing Director Reid.
"As the market develops there's no doubt going to be opportunity in the commercial, industrial, and perhaps also in the off grid, or grid support type batteries at a larger scale."
While Australia's electricity market is relatively small, it's a high-income Western nation where global warming is a live political issue, said Matthew Boyle of consultancy CRU in Sydney.
"It's a similar market to the U.S. for example, but on a smaller scale, so battery manufacturers can try things out before releasing products elsewhere."
For her family home, Miao chose an Australian-engineered Ecoult battery, owned by U.S. battery producer East Penn and using technology developed by Australia's national science body, CSIRO.
"It's about changing the mentality of how we use our energy and electricity, it's about reducing our dependence on coal," she said.
Ecoult's lead-acid system, which allows batteries to operate in a partial state of charge, is already being used to power King Island off Australia's southern mainland, a producer of high quality dairy, beef and other food products, enhancing its green reputation.
East Penn plans to launch a smaller scale version in the fourth quarter and is commercialising the technology in the United States, which is modernising its power grid.
"We've got a very large, strong team in the Americas and we're working with Ecoult on how best to start introducing the platform and products that we've developed," said East Penn senior vice president, industrial sales, Bruce Cole.
"Ultimately there should be opportunities globally." ($1 = 1.3856 Australian dollars)
(Reporting by Melanie Burton and Byron Kaye; Editing by Richard Pullin)
(This news story is from Reuters)