Commercial concentrated solar one step closer

A first-of-a-kind concentrated solar thermal power project with a total project cost of more than $200 million is set to progress thanks to ARENA funding.

ARENA is backing a first-of-a-kind concentrated solar thermal power (CSP) plant in Port Augusta, South Australia.

The $203 million project is now conditionally approved to receive up to $65 million in ARENA support. The funding becomes available once the project reaches financial close, expected in late 2023.

Australian company Vast Solar will build the 30 MW / 288 MWh plant (called VS1) using its modular CSP technology.

Expected to enter commercial operation in late 2025, the project seeks to demonstrate the technical and operational viability of the technology at utility scale. If successful, the project will show concentrated solar thermal power can supply scalable and dispatchable renewable energy to the Australian market.

The video below, recorded in 2018, both explains the basic principles of concentrated solar thermal power and anticipates its growing role in the commercial renewable energy mix.

ARENA CEO Darren Miller said the expansion of Vast Solar’s technology into a commercial scale project shows  concentrated solar thermal technology could play a significant role in additional ways to generate and store renewable energy at scale.

“With the increasing need for dispatchable renewable generation and longer duration energy storage, concentrated solar thermal has potential to assist Australia’s energy transition alongside pumped hydro and large scale batteries,” Mr Miller said.

“Vast Solar is a globally recognised leader in solar thermal technology innovation. Combined with its significant technical and commercial expertise, that means they are well placed to deliver Australia’s first large scale CSP plant, which should supply power at a commercial cost, competitive with other forms of renewable generation.”

What is CSP?

Concentrated solar thermal farm
Many earlier concentrated solar thermal power plants have been vast, science fiction-like structures

CSP (sometimes referred to as CST) uses mirrors – also known as heliostats – to concentrate the sun’s heat onto high temperature solar receivers.

Vast Solar uses liquid sodium to transfer the heat, which is then stored in molten salt reservoirs.

The stored thermal energy is then available to create steam, power a turbine and produce electricity. Or, for direct use in  decarbonising some industrial processes.

One of the benefits of CSP over photovoltaic solar panels is its cost-effective long storage time. This means that CSP can generate electricity or provide heat on demand, including overnight.

Globally, most CSP plants used for electricity production incorporate 3-15 hours of thermal energy storage.

Chemical batteries used to store electrical energy also rely on in-demand or rare constituents such as lithium and cobalt. Whereas sodium is the sixth most common element on Earth and salts suitable for energy storage are also relatively abundant.

Modular design

Vast Solar feature image
Vast Solar’s prototype manufacturing facility (Image: Vast Solar)

Some versions of concentrated solar thermal power look like science-fiction illustrations made real.

Hundreds of heliostats arranged in geometric patterns focus the sun’s power onto a single receiver atop a huge central tower. These arrays are on a grand scale. The trouble is, should anything break down in the central “tower of power”, it affects the whole system.

Vast Solar takes a modular approach. Its arrays, while still using multiple heliostats, are smaller and focus on less imposing towers. The technology is scalable by incorporating more mirrors and more towers in repetitive arrays.

Vast Solar says their system uses prefabricated mirrors and smart control of multiple solar collectors. Combined, those two factors deliver lower costs and more efficient energy capture and storage.

ARENA has supported the Vast Solar technology since 2012. Funding has included $9.9 million towards the 1.1 MW CSP Pilot Plant in Jemalong, New South Wales.

Craig Wood, CEO of Vast Solar said: “We are grateful for ARENA’s long-term support. Their understanding of the potential of our CSP technology is a testament to the Australian Government’s ambition to deliver cost-competitive dispatchable renewable energy to help uphold emissions reductions goals while supporting local jobs and industry.”

The Australian Government and ARENA have also provided Vast Solar with $19.48 million in conditional funding through the co-operative  HyGATE initiative with Germany. The funding supports Vast Solar’s Solar Methanol production plant, a 10 MW electrolyser producing green hydrogen for solar methanol production.

About 10 – 20% of the electricity and heat generated by VS1 will power the electrolyser.