Has the shine worn off the promise of vast amounts of cheap, reliable base load power from giant solar thermal power plants?

Key points: SolarReserve could not secure funding for the Port Augusta project

SolarReserve could not secure funding for the Port Augusta project An expert says a similar plant in America has had trouble with its performance

An expert says a similar plant in America has had trouble with its performance Dubai's "mega" solar park is pressing ahead and another has been finished in Morocco

It is a question stemming from the scrapping of South Australia's $650 million SolarReserve Aurora Solar Energy Project, which had been lauded by former premier Jay Weatherill and the City of Port Augusta, as both grappled with the closure of the city's coal-fired power station.

The Port Augusta project won an energy supply contract with the SA Government, and a $110 million loan from the Commonwealth, but still failed to find enough private financial backers.

How does it work?

The plants use a giant field of mirrors to concentrate sunlight onto a tall tower, where molten salt is heated.

The heat created is then used to generate steam and the energy is stored for up to several hours.

When the project was announced in 2017, Solar Reserve said the plant would be able to provide between eight and 10 hours of storage and had no requirement for gas or oil-generated electricity as a backup.

"It's a major blow, because concentrated solar power (CSP) systems are at a far smaller scale in terms of market deployment, than some of the other renewable technologies like photovoltaics and wind," Australian National University's solar thermal expert John Pye said.

"Right now, it would be nice to see every project succeeding, but it's not that this is the only great golden hope of the industry."

SolarReserve's power plant in Nevada uses mirrors to create steam. ( Supplied: SolarReserve )

'Problems' for similar plant in USA

SolarReserve runs a similar plant — Crescent Dunes in the United States — where output has not met all of its goals.

Dr Pye said there was data showing its performance was under a cloud.

"They might be having problems with control systems, they might be having problems with heat exchanges — these are difficult systems to operate let alone build, because every day the sun comes up, the sun goes down, things get hot and things get cold," he said.

"This is very far away from the operating conditions a traditional fossil fuel power station has to deal with, so there are important technical challenges the companies in this sector have been trying to overcome."

Keith Lovegrove, the managing director of renewable energy engineering and advice firm ITP Thermal, visited Crescent Dunes last month.

"The day we were there, it was working very well, so the technology is fundamentally sound," he said.

Could an international bid be the answer?

The State Government will put out a new tender for its electricity supply contract, but has not ruled out a fresh bid based on SolarReserve's solar thermal project.

Dr Lovegrove suggested the Government proactively put the Port Augusta project out to a competitive international bid.

"We know SolarReserve, to their credit, have done a lot of work, they've found a site, they've got the approvals for connection, they've got the environmental approvals," he said.

"The site, in a sense, is ready to go — there's no reason why another group couldn't take it up."

Sorry, this video has expired The Port Augusta coal power station chimney being demolished.

'Mega' solar park pressing ahead in Dubai

Even if solar thermal ultimately fails to proceed in Port Augusta, there are similar projects going ahead overseas.

Work on Morocco's Ouarzazate Solar Power Station has recently been completed, while Dubai is pressing ahead with a "mega" solar park.

"That's a new project and they've recently passed through the stage that Port Augusta didn't get through, which is achieving financial close," Dr Pye said.

"Every project is precious, but there are dozens — I think it's nearly 100 — CSP projects around the world and there are plenty of them that have been operating for years, successfully."

He pointed out that an Australian firm — Vast Solar — had demonstrated solar thermal technology using smaller, modular towers.