Molten Silicon thermal energy storage system has higher energy density and ten times lower cost than lithium ion batteries for utility storage

1414 Degrees had its origins in patented (Australian) CSIRO research and has built a prototype molten silicon storage device which it is testing at its Tonsley Innovation Precinct site south of Adelaide.

Chairman Kevin Moriarty says 1414 Degrees’ process can store 500 kilowatt hours of energy in a 70-centimeter cube of molten silicon – about 36 times as much energy as Tesla’s 14KWh Powerwall 2 lithium ion home storage battery in about the same space.

Put another way, he says the company can build a 10MWh storage device for about $700,000. The 714 Tesla Powerwall 2s that would be needed to store the same amount of energy would cost $7 million before volume discounts.

1414 Degrees has raised $500,000 of a $2 million seed capital issue that it hopes to complete by the end of next month. It is in talks with a hydroponic herb farm and wind farm suppliers about pilot commercial scale trials of its technology, and is planning a $10 million public share issue to fund construction of the first two 200 megawatt hour units.

* thermal energy storage system (TESS) storing energy as latent heat in molten silicon
* sizing of systems from 10 to 100’s of megawatt hours for grid, off-grid and co-generation sites
* energy is stored as latent heat at 1414° C providing maximum efficiency of energy output
* low maintenance, low cost and low impact compared to lithium-ion batteries
* wide range of uses in district heating, industrial complexes and shopping centres as well as grids
* Prototype TESS commissioned
* Better than expected ERD efficiency of 31% electricity and 80% CHP
* AusIndustry signs off and concludes its 50% funding of the Prototype
* Testing and design underway for commercial 10MWh and 200MWh module

Mr Moriarty is counting on 40 per cent to 50 per cent of the cost of these initial devices being funded by government subsidies because of the unique technology. The device stores electrical energy by using it to heat a block of pure silicon to melting point – 1414 degrees Celsius. It discharges through a heat-exchange device such as a Stirling engine or a turbine, which converts heat back to electrical energy, and recycles waste heat to lift efficiency.

Pure silicon is a shimmering, blue-grey “metalloid” – a substance that exhibits characteristics of metals and non-metals. A byproduct of smelting metal quartz ores, it is abundant and cheap. It is attractive as a storage medium because it is stable at the 1414 degree melting point, and can hold the heat for a week or two with adequate insulation although 1414 Degree’s devices are designed to charge and discharge daily.

If the claims stand up at commercial scale the molten silicon storage device could be one of the technological breakthroughs that make it cheaper to store energy from wind and solar farms. This could smooth out their intermittent generation and also help prevent or isolate blackouts from transmission failures during storms such as the one that hit South Australia in September.

Still, 1414 Degrees is only one of a growing number of companies seeking to push the frontiers of storage technology in Australia and win a role in the the energy grid of the future, which is evolving from one dependent on “baseload”.

Rather than just sell its storage devices, 1414 Degrees wants to enter into joint ventures with customers – or partners – and share in the benefits. For example, Mr Moriarty said its devices could increase the revenue of a wind farm by 25 per cent, through increased output and exploiting higher wholesale prices when the wind isn’t blowing. For a hydroponic farm, it can provide heat as well as electricity.

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