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The Energy Innovators: Wes Stein on the future of concentrated solar thermal

“Electricity never used to be this difficult and it was never this much fun, either.”

The CSIRO’s chief solar scientist Wes Stein, in his address to energy leaders at an ARENA summit in Canberra, hit the nail on the head.

With more diversity of supply than ever before in the electricity market, ensuring the system works reliably and equitably is a complex task. But it’s also brimming with innovation and new ideas and Stein says Concentrated Thermal Solar technology is a source of untapped potential here in Australia.

In his address to ARENA’s Innovating Energy Summit, Stein outlined the steps needed for Australia to capitalise on what CST (or CSP, concentrated solar power) can deliver. It’s one in a series of lightning talks we’re presenting by leading thinkers in renewable energy – scroll down further for his Q&A session with ARENA’s Phil Cohn.

“One of the attractions of CSP is that you can integrate nicely with other thermal power sources, not just through the grid but actually on site,” he said. “We could over time see the level of gas dropping and the level of thermal energy storage integrated with a solar thermal plant increasing.”

CST can be generated in a number of ways but a popular approach uses a field of heliostat mirrors to follow and reflect the sun’s heat on to a solar receiver. Sodium or molten salt is pumped up to the receiver and returned to a hot tank where it is stored until needed.


READ MORE: Three remarkable ways solar thermochemistry could reshape Australian industry

It has been used for decades overseas but few Australian projects exist. ARENA has invested $35 million in the establishment of the Australian Solar Thermal Initiative (ASTRI) to enable Australian universities to collaborate with US institutes and companies on “over the horizon” initiatives, and last year ran a request for information on the technology.

Stein said investing in research and development was “critical” for the Australian industry and while the greatest costs would come early, he predicted the price of rolling out CST plants would decrease quickly.

“Certainly the first projects that we build will be expensive that’s for sure, but very quickly the electricians, the concreters, the boiler makers will sharpen their pencils and say “I’ve built one of those before; now my cost will be 20 percent lower.”

He said there were currently 2 million square metres of solar collectors operating commercially worldwide, with Spain alone building 2.4 gigawatts-worth in a couple of years. Morocco, Saudi Arabia and the United Arab Emirates have all invested in CST but it is in China’s plan to double the world’s CST installations by 2020 that Stein sees the most potential for the CSIRO and Australian industry.

“There is a dying need for projects to be built here locally but right now I’m getting most interest from overseas and particularly from China,” he said. “They want to double the world’s production capacity in the next four years, they haven’t got the time to develop heliostats and the technology themselves so they’re buying it from elsewhere so that could potentially be quite lucrative for CSIRO.”


Paving the way for concentrated solar thermal in Australia

The Australian Renewable Energy Agency (ARENA) today released a report outlining how concentrated solar thermal (CST) technology could be a commercially viable form of dispatchable renewable energy within a decade.

Last year, ARENA called for industry participants worldwide to respond to a Request for Information (RFI) exploring the potential for solar thermal to be rolled out in Australia. A total of 31 responses were received from both Australian and international companies.

These responses will now inform ARENA in preparing a strategy to support CST in Australia, including considering future funding opportunities for CST.

ARENA is also funding a roadmap for CST to examine requirements for accelerating commercial deployment in Australia. The roadmap is underway and will be completed in mid 2018, with the results also used to inform ARENA’s CST strategy.

CST systems use mirrors to concentrate and convert sunlight to heat at high temperatures. The heat is then stored and used to produce steam, which is then run through a turbine to generate electricity.  Most CST plants are large scale and incorporate between 3-15 hours of thermal energy storage.

Large scale CST technology is yet to be introduced in Australia, but there are approximately 100 utility scale CST plants operating worldwide, mostly in the United States and Spain totalling around 5GW. The total CST capacity is expected to double to 10 GW over the next five years, driven by new plants in China, South America and Africa.

The report released today, which was prepared by ITP Thermal, found strong confidence in the future of CST, with a number of global industry leaders interested in being involved in the deployment of CST in Australia.

All responses highlighted that CST could help to address Australia’s energy storage and dispatchability needs by providing reliable, responsive and flexible electricity generation at any time of day or night.  Respondents noted that CST plants operate in a way similar to that for existing thermal power stations, allowing them to be easily incorporated within the electricity network. Respondents also noted the cost of CST is expected to fall in the coming years.

ARENA CEO Ivor Frischknecht said the RFI was an important stepping stone towards bringing commercial scale CST to Australia.

“While still not cost-competitive with other forms of new-build power generation, the ability to store energy and be able to dispatch renewable energy at any time will be of increasing value, and this information shows there is strong support for CST,” he said.

“We are now considering funding opportunities to assist in creating a pathway for CST to become commercially viable in Australia in the coming years,” Mr Frischknecht said.

In the meantime, Mr Frischknecht said ARENA welcomes applications for a well developed CST project under ARENA’s Advancing Renewables Program which provides funding for renewable energy projects year-round.

“While we are busy working out our roadmap for the industry, our door is always open to high quality, innovative renewable energy demonstration projects that can help bridge the gap to commerciality for new technologies.

“If any company has a prospective project with well developed financing, an offtake agreement and technical details mapped out, they don’t need to wait and we would encourage them to apply,” he said.

ARENA is also currently working with the Clean Energy Finance Corporation (CEFC), in consultation with the Infrastructure and Project Financing Agency (IPFA), to provide the Commonwealth Government with advice on Solar Reserve’s 150MW Aurora CST project proposed for Port Augusta, including its suitability for a federal loan of $110 million.

ARENA media contact:

0410 724 227 |

Download this media release (PDF 117KB)

World-leading solar technology, born in Melbourne? That’s ultra-cool.


The researcher trains his blowtorch on a small panel, little bigger than a credit card. After repeated torching he reaches out his hand. It is cool to the touch.

It’s an impressive sight that cuts to the heart of the world-leading technology being created here in a Melbourne high tech manufacturing facility, and it’s a breakthrough technology that ARENA is proud to contribute additional funding for.

ARENA is announcing a $4.8 million funding boost for the company behind this technology, RayGen, which will use the money to expand its pilot project. The money is part of  $9.6 million equity raising effort from the company.

The new technology, dubbed PV Ultra, offers hope of being far  more efficient than traditional solar photovoltaic panels for a significantly lower cost.


These small “ultracool” modules are part of the receivers,  destined for RayGen’s concentrated solar field at Newbridge in regional Victoria.

There, the world-leading technology created by RayGen captures the power of the sun from a field of automatically controlled mirrors (called heliostats), and amplifies this energy 650 times.

Central tower at the RayGen solar farm. IMAGE: RayGen.

The concentrated light is then directed towards a central tower where a custom designed photovoltaic receiver converts the energy into electricity.

By converting the energy of the sun with such high efficiency, RayGen’s technology offers serious potential to reduce capital costs in both manufacturing and deployment of solar energy.


In 2016 RayGen, with ARENA’s funding support, completed the 200kW pilot project at Newbridge, just outside Bendigo. The project provided energy for a nearby mushroom farm, and also allowed RayGen to collect performance data and prove the efficiency of the system and understand how the technology can be manufactured and deployed at scale.

ARENA’s additional funding will now help expand the completed pilot project to a demonstration phase and will supply not only electricity but process heat to the site. It pushes RayGen one step closer to commercially deploying the technology and has the potential to create many more local high tech manufacturing jobs as the business scales up over the next decade.

ARENA CEO Ivor Frischknecht said the demonstration was an important step for the technology in Australia.

“This is an exciting opportunity for ARENA to invest in RayGen, an Australian-based solar technology business, that is really leading the world in concentrated solar PV and making great progress in making it commercially viable, Mr Frischknecht said.

World leading technology is being made at the company’s Melbourne headquarters. IMAGE: RayGen.



When John Lasich founded RayGen in 2010 the company consisted of three people and one big idea.

As a researcher at Victoria University, he completed his PhD on the subject of concentrated solar systems. Years later, RayGen gave him the opportunity to put his ideas into practice.

Since then, the company has grown to employ 27 people. These are high-tech jobs creating a high-tech product that could soon be exported to the world.

“We’re a small startup with a lot of experience in energy and solar energy,” he says.

“What we did was take our experience and create a new technology that has all the key elements we need to allow us to manufacture here in Australia.”

It’s small, for one. The receiver’s size means it can be affordably produced and can be exported in large numbers without prohibitive cost.

“This is a very small, very powerful module,” he says. “That’s our secret sauce.”

Just 4m2 of PV Ultra can produce as much energy as 5000m2 of conventional, silicon-based solar panels (though 2500m2 of heliostats are required to direct light onto it).


The high-tech part of the system – the receiver – will be made in Australia and exported to the world. That means in future, the more easily-produced parts of the system (such as the heliostats) can be produced in-country by partners in each export market.

Heliostats track the sun at RayGen’s solar farm. IMAGE: RayGen.


The technology combines various elements of solar PV, concentrated solar thermal and CPV to deliver a low-cost energy solution and addresses issues like high capital costs and inefficiencies in capturing light that have traditionally been barriers to deploying standard CPV technology.

RayGen’s unique module is a box small enough to fit in the palm of your hand. It employs technology typically used in satellite applications in space to convert concentrated light directly into electricity.

The RayGen heliostat mirrors move to track the sun, delivering a concentrated light beam to the array of PV Ultra modules in the receiver. The receiver is linked to the mirrors by automated wireless software ensuring maximum output throughout the day as the mirrors follow the sun.

ARENA’s analysis of the project indicates that the technology has the potential to achieve a cost of less than $100/MWh once deployments reach a cumulative scale of 100MW.

To put that in context, industry sources estimate the cost of wind generation at $60-80 per MWh with solar PV now also within this cost range. Each of these technologies has an installed base of more than 100 GW.

Following the next project at Newbridge, RayGen is also preparing for a larger 11MW project in China, with RayGen’s Chinese partner and shareholder, Zhou Zhou Intense Solar managing construction with RayGen providing the receiver, control system and project design.


Holding a mirror up to the future. What is CST?

Solar power is an essential element in Australia’s future energy mix, that much is clear. But it’s not just the solar you most likely know – photovoltaic technology – that will probably replace the coal fired power generators of today.

Technology based on something as simple as a mirror could be one of the answers to long term, renewable electricity supply in Australia.

Meet concentrated solar thermal. Some versions of the technology look like dramatic interlopers from a futuristic age. Huge arrays of heliostats point at domineering structures known as “towers of power” like something cooked up by a Bond-film villain. Others look like rows and rows of giant gleaming dishes, more at home on the set of a sci-fi movie than a power station.

And yet, Concentrated Solar Thermal (CST) power stations have been operating for more than 30 years. There are now more than 5 GW of installed capacity around the world, most of it in the United States and Spain.


CST, like photovoltaic technology (PV), harnesses the sun’s energy and turns it into electricity. The difference between them is that PV converts the radiation directly into electricity, while CST directs a system of mirrors to focus light from the sun to one small point. It then converts the accumulated energy into heat which can be stored before it is later turned into electricity.

While it’s based on the same idea as PV (converting solar energy to electricity) the major advantage CST has over PV is the built in ability to provide up to 15 hours or more of stored energy, long enough to last through the night. That allows it to provide demand responsive electricity outside of daylight hours. And if not used, that stored energy can be retained for many weeks.


Given its ability to deliver stored energy on demand, CST could represent an alternate source for the reliability offered by coal fired generators.  But in providing this demand response role, CST is not intended as a replacement for PV or wind technology, rather it would be a complement to them as we adopt more and more renewable energy

PV and wind turbines have become cheaper and cheaper as ways of generating electricity when they are working, but their output is variable (it needs sun and wind). Because of this they require back up from the national grid or another generator to provide energy when sunlight or wind isn’t available. Battery storage or pumped hydroelectric storage are the subject of much interest as a solution to this but CST could also provide a cost effective solution.

A ‘tower style’ CST farm. IMAGE: Keith Lovegrove.


While PV can be installed at the household level or at very large solar farms CST isn’t suitable for small scale installation, it’s a complex system that requires steam turbines and needs economies of scale to make it viable.

The capital costs are currently higher than they are for coal or gas generators of equivalent size, the difference is that there are no ongoing fuel costs, and zero emissions.

Keith Lovegrove, Managing Director of ITP Thermal, estimates that the total cost of energy per MW hour of a new gas fired generator would be roughly the same as a new CST generator, and that’s without considering any potential cost of carbon.


There are a four commonly acknowledged kinds of mirror configurations in CST plants.

Parabolic troughs account for around 90% of the currently operational CST technology. This is the most commercially mature configuration, with 30 years of operation in California proving its viability. However, this method is comparably cost inefficient when it comes to integrating thermal energy storage in standard configurations.

A ‘parabolic trough’ style CST installation. IMAGE: Rebecca Dunn.

Linear Fresnel is a less mature, but very promising, technology. Research shows it has similar performance as parabolic troughs, but proponents argue is much cheaper to build.

Towers surrounded by mirror fields are the new fashion in CST, and are progressing at pace. About half of all the CST plants currently under construction around the world are tower configurations. At the moment, it appears that the tower/molten salt storage combination is the most cost effective of all the currently installed CST technologies.

Dish is the least mature technology, research has proven it’s highly efficient, but it needs more development before it’s commercially viable.

Despite the variations in the type of mirrors used, the generator plant configuration almost always remains the same.

Liquid is heated by the light collected from mirrors, transferred to molten salt for storage, and then used to heat water to power steam turbines, the same ones used in old style coal fired generators, but without carbon dioxide emitting coal.


ARENA has established the Australian Solar Thermal Research Initiative (ASTRI) to undertake research that will improve the efficiency and operation of future CST systems, while lowering costs. With $35 million in funding over 8 years, ASTRI’s key activities include higher temperature systems and more efficient power generation.

ARENA is currently calling for information from industry participants on the costs and benefits of CST. This information will help ARENA and the CEFC to determine the scope and focus of government assistance for the deployment of CST in Australia.

A ‘linear fresnel’ style CST installation. IMAGE: AREVA Solar.

It is the first step in exploring how concentrated sunlight could generate reliable, affordable renewable energy with built-in storage for our national grids.


ARENA’s new call aligns with the Federal Government’s offer to make up to $110 million available for an equity investment to accelerate and secure delivery of a concentrated solar thermal (CST) project in Port Augusta.

Despite the expectation that proven CST technology will be implemented in a large-scale plant at Port Augusta, some of the more cutting edge technology, like graphite storage and dish systems, will likely make it onto the list of technology to consider for smaller pilot-scale projects.

The options are varied, exciting and potentially game changing for Australia’s energy mix.