Origin-backed energy storage start-up unveils “breakthrough” redox flow battery

Origin Energy-backed storage hopeful Allegro Energy has unveiled its proprietary battery technology for the first time this week at an open day event held at its company headquarters in Thornton, New South Wales.

The unveiling, on Wednesday, gave a first-ever glimpse at the company’s locally manufactured microemulsion flow battery (MeFB) technology, following the news earlier this week that Allegro secured a US patent for its technology.

Allegro Energy CEO and co-founder Thomas Naan says the patented technology delivers a “breakthrough” in long duration storage technology that will “support the clean energy transition in Australia and globally.”

According to Allegro, its MeFB technology offers increased scalability, sustainability and performance over existing technologies at a lower cost and higher degree of safety.

Unlike more prevalent solid-state battery technology, such as lithium-ion based solutions, Allegro’s MeFBs are a type of redox flow battery.

Put simply, in redox flow batteries, energy is stored in liquid electrolytes stored in two separate tanks. During discharge of the battery, pumps circulate the electrolytes through a central electrochemical cell where energy conversion takes place.

Inside the cell, two electrodes cause the electrolytes to undergo a reduction or oxidation reaction (hence the name redox). During reduction, the electrolyte gains electrons and during oxidation, the other electrolyte loses electrons.

The electrons released from this process flow through an external circuit to generate electricity. During charging, this process is reversed.

Risk of thermal runaway minimised

Although other companies have explored the use of redox batteries at utility-scale, Allegro claims its water-based microemulsion electrolyte to be a world first.

In this case, a microemulsion is a mixture made up of tiny droplets of one liquid evenly spread throughout another liquid with the help of a stabiliser, known as a surfactant.

According to the company, the use of its non-flammable and non-toxic water-based microemulsion electrolyte means the batteries are not only fully-recyclable, but the risk of thermal runaway is hugely reduced.

Although the exact composition of its MeFB remains proprietary, Allegro claims all raw materials it uses are readily available at gigawatt scale without the need for mining.

For shorter duration and higher power requirements, Allegro is manufacturing supercapacitors that also use its proprietary MeFB technology.

Origin Energy bets on MeFBs

In 2023, Origin Energy acquired a 5% stake in Allegro Energy and committed to trial the company’s technology through the deployment of a 100kW/800kWh MeFB project located at its Eraring coal plant in New South Wales.

Origin has since increased its support to Allegro after it committed further investment as part of a $US17.5 million Series A funding round which closed during September last year.

The funding and commitment from Origin is a good sign for Allegro, which will be keen to avoid the fate of fellow Australian-based flow battery specialist, Redflow. 

Last year, the pioneering Brisbane-based company was placed into voluntary administration after it failed to secure funding.