There’s an Adelaide based company designing and testing a thermal energy storage system that uses silicon heated to 1400+ degrees C to store energy. The website is unfortunately very geared towards investors but I’m interested if this is actually a commercially viable method of storing energy.

The idea in it’s best form seems to be that these units could complement wind and solar power generation, taking excess supply and storing it to be used to drive electricity producing turbines when there is no wind or Sun to be seen. The company claims it will be very low maintenance and match or better the efficiency of batteries.

Can anyone see any obvious flaws with the concept? How would this compare to Elon Musks’ big battery that was recently built in SA?

Researching it a little there is a similar effort taking place in Spain (https://www.engineersaustralia.org.au/News/store-and-generate-energy-using-molten-silicon) except rather than using the stored heat to drive turbines they look to be developing thermophotovoltaic cells that will generate electricity directly from the incandescent energy of the heated silicon! Could useful amounts of electricity be generated this way?

https://1414degrees.com.au/what/

Our patented Thermal Energy Storage System (TESS) takes electricity from any source, the grid or renewables, and stores as latent heat in molten silicon at 1414° Celsius.

Latent heat is energy that is held in a phase change material when it becomes molten. Silicon’s very high melting point, 1414° Celsius, means it can hold much more energy than other phase change materials. It delivers maximum energy efficiency.

The energy from the latent heat is passed through an energy recovery system and a turbine to dispatch heat and electricity when required. It transforms intermittent renewable electricity by providing reliability and stability identical to that of a coal or gas fired power station.

The system will last at least 20-30 years and works at its optimal capacity when constantly active. It is designed for minimal maintenance and is environmentally benign.

The result is low cost and clean storage of energy providing a stable supply for heat consumers and to the grid – a critical requirement as renewable generation increases.

Molten salt as the storage carrier is another that I’ve seen used.

esselte said:

There’s an Adelaide based company designing and testing a thermal energy storage system that uses silicon heated to 1400+ degrees C to store energy. The website is unfortunately very geared towards investors but I’m interested if this is actually a commercially viable method of storing energy.

The idea in it’s best form seems to be that these units could complement wind and solar power generation, taking excess supply and storing it to be used to drive electricity producing turbines when there is no wind or Sun to be seen. The company claims it will be very low maintenance and match or better the efficiency of batteries.

Can anyone see any obvious flaws with the concept? How would this compare to Elon Musks’ big battery that was recently built in SA?

Researching it a little there is a similar effort taking place in Spain (https://www.engineersaustralia.org.au/News/store-and-generate-energy-using-molten-silicon) except rather than using the stored heat to drive turbines they look to be developing thermophotovoltaic cells that will generate electricity directly from the incandescent energy of the heated silicon! Could useful amounts of electricity be generated this way?

https://1414degrees.com.au/what/

Our patented Thermal Energy Storage System (TESS) takes electricity from any source, the grid or renewables, and stores as latent heat in molten silicon at 1414° Celsius.

Latent heat is energy that is held in a phase change material when it becomes molten. Silicon’s very high melting point, 1414° Celsius, means it can hold much more energy than other phase change materials. It delivers maximum energy efficiency.

The energy from the latent heat is passed through an energy recovery system and a turbine to dispatch heat and electricity when required. It transforms intermittent renewable electricity by providing reliability and stability identical to that of a coal or gas fired power station.

The system will last at least 20-30 years and works at its optimal capacity when constantly active. It is designed for minimal maintenance and is environmentally benign.

The result is low cost and clean storage of energy providing a stable supply for heat consumers and to the grid – a critical requirement as renewable generation increases.

They have had similar projects being tested for quite a while using salt, haven’t heard much about that of late.

There’s an existing solar farm just outside Port Augusta that uses salt.

Bunch of mirrors surrounding a 200ft tall tower, focused on the top of that tower. Salt is pumped to the top, heated to molten and then back to ground level where it is stored.

The main difference in the storage medium here seems to be that silicon can store far more energy per cubic meter than salt.

The basic idea is OK in principle because for large scale storage it might be much cheaper than batteries, and possibly would have a longer life span.

It might also not work out as cheap as hoped, really have to try it and see.

But thermal storage as efficient (or nearly as efficient) as batteries? No way.

You could certainly store most of the generated energy as heat (as long as you don’t want to keep it too long), but converting it back to electricity you will get less than 50% back.

Unless they have discovered a basic flaw in the laws of thermodynamics.

I didn’t know we had any solar thermal plants in Australia by the way.

I wonder how that is going.

Also heat storage with solar thermal makes much more sense.

You are going to lose more than half when you convert the heat into electricity anyway, so if you store the surplus heat directly then you still only have the one generation loss.

esselte said:

The energy from the latent heat is passed through an energy recovery system and a turbine to dispatch heat and electricity when required. It transforms intermittent renewable electricity by providing reliability and stability identical to that of a coal or gas fired power station.

The system will last at least 20-30 years and works at its optimal capacity when constantly active. It is designed for minimal maintenance and is environmentally benign.

The result is low cost and clean storage of energy providing a stable supply for heat consumers and to the grid – a critical requirement as renewable generation increases.

OK, it looks like their efficiency calculations are based on transporting and using the “waste” heat as well.

Good luck with that in Australia.

There could be a market I guess, but it would be pretty small.

The Rev Dodgson said:

esselte said:

The energy from the latent heat is passed through an energy recovery system and a turbine to dispatch heat and electricity when required. It transforms intermittent renewable electricity by providing reliability and stability identical to that of a coal or gas fired power station.

The system will last at least 20-30 years and works at its optimal capacity when constantly active. It is designed for minimal maintenance and is environmentally benign.

The result is low cost and clean storage of energy providing a stable supply for heat consumers and to the grid – a critical requirement as renewable generation increases.

OK, it looks like their efficiency calculations are based on transporting and using the “waste” heat as well.

Good luck with that in Australia.

There could be a market I guess, but it would be pretty small.

Yeah, didn’t mention that part because it didn’t make much sense to me either. Maybe in colder climates, but then how would they actually move the heat from the central unit to the buildings that they want to heat? I can’t imagine it would be big insulated ducts with hot air wafting through them, so would they pump the molten silicon to heat exchangers at the buildings to be heated instead? Can you even pump molten silicon around a suburb sized neighbourhood? Not without expensive infrastructure I’m guessing.

esselte said:

The Rev Dodgson said:

esselte said:

The energy from the latent heat is passed through an energy recovery system and a turbine to dispatch heat and electricity when required. It transforms intermittent renewable electricity by providing reliability and stability identical to that of a coal or gas fired power station.

The system will last at least 20-30 years and works at its optimal capacity when constantly active. It is designed for minimal maintenance and is environmentally benign.

The result is low cost and clean storage of energy providing a stable supply for heat consumers and to the grid – a critical requirement as renewable generation increases.

OK, it looks like their efficiency calculations are based on transporting and using the “waste” heat as well.

Good luck with that in Australia.

There could be a market I guess, but it would be pretty small.

Yeah, didn’t mention that part because it didn’t make much sense to me either. Maybe in colder climates, but then how would they actually move the heat from the central unit to the buildings that they want to heat? I can’t imagine it would be big insulated ducts with hot air wafting through them, so would they pump the molten silicon to heat exchangers at the buildings to be heated instead? Can you even pump molten silicon around a suburb sized neighbourhood? Not without expensive infrastructure I’m guessing.

Steam. We need to build a series of pipes that can move steam around. That’ll do the job.

sibeen said:

Steam. We need to build a series of pipes that can move steam around. That’ll do the job.

One step closer to the dream of a steampunk future!

sibeen said:

esselte said:

The Rev Dodgson said:

OK, it looks like their efficiency calculations are based on transporting and using the “waste” heat as well.

Good luck with that in Australia.

There could be a market I guess, but it would be pretty small.

Yeah, didn’t mention that part because it didn’t make much sense to me either. Maybe in colder climates, but then how would they actually move the heat from the central unit to the buildings that they want to heat? I can’t imagine it would be big insulated ducts with hot air wafting through them, so would they pump the molten silicon to heat exchangers at the buildings to be heated instead? Can you even pump molten silicon around a suburb sized neighbourhood? Not without expensive infrastructure I’m guessing.

Steam. We need to build a series of pipes that can move steam around. That’ll do the job.

Superheated steam at 600 psi.

sibeen said:

esselte said:

The Rev Dodgson said:

OK, it looks like their efficiency calculations are based on transporting and using the “waste” heat as well.

Good luck with that in Australia.

There could be a market I guess, but it would be pretty small.

Yeah, didn’t mention that part because it didn’t make much sense to me either. Maybe in colder climates, but then how would they actually move the heat from the central unit to the buildings that they want to heat? I can’t imagine it would be big insulated ducts with hot air wafting through them, so would they pump the molten silicon to heat exchangers at the buildings to be heated instead? Can you even pump molten silicon around a suburb sized neighbourhood? Not without expensive infrastructure I’m guessing.

Steam. We need to build a series of pipes that can move steam around. That’ll do the job.

They actually do that some places.

With high density cities and very cold winters.

Adelaide doesn’t score too well on either of those criteria.

It may be in the future solar thermal power plants will be combined with industrial plants that have a high demand for heat, but it’s not going to happen while electricity is still cheap, and it may be it makes more sense to use surplus wind power to generate the heat where it is required.

The Rev Dodgson said:

Adelaide doesn’t score too well on either of those criteria.

Is there a reason it couldn’t be exported to colder climes if it proves successful? They hold patents in a few countries already and have applied for others.

Their market is not restricted to Adelaide, is what I’m saying.

The Rev Dodgson said:

They actually do that some places.

I was thinking about New York when I wrote it :)

esselte said:

The Rev Dodgson said:

Adelaide doesn’t score too well on either of those criteria.

Is there a reason it couldn’t be exported to colder climes if it proves successful? They hold patents in a few countries already and have applied for others.

Their market is not restricted to Adelaide, is what I’m saying.

Could make sense in conjunction with Wind Power in N Europe and maybe Canada.

Depends on cost vs the competition.

What about storing the energy as cold – say liquid nitrogen? Use a big Stirling Engine powered by solar thermal at one end as the heat source to directly power a mechanical refrigeration machine to make liquid nitrogen. Store and use the liquid nitrogen as required to provide the cold end of a second Stirling Engine to spin a genny.

party_pants said:

What about storing the energy as cold – say liquid nitrogen? Use a big Stirling Engine powered by solar thermal at one end as the heat source to directly power a mechanical refrigeration machine to make liquid nitrogen. Store and use the liquid nitrogen as required to provide the cold end of a second Stirling Engine to spin a genny.

Put out a prospectus (nice and glossy), make yourself managing Director on a hefty retainer, get a wet behind the ears journalist to do some stories about it in the popular media then fold the company up in 3 years time and go and live in Monaco.

Why silicon? It’s expensive.

Peak Warming Man said:

party_pants said:

What about storing the energy as cold – say liquid nitrogen? Use a big Stirling Engine powered by solar thermal at one end as the heat source to directly power a mechanical refrigeration machine to make liquid nitrogen. Store and use the liquid nitrogen as required to provide the cold end of a second Stirling Engine to spin a genny.

Put out a prospectus (nice and glossy), make yourself managing Director on a hefty retainer, get a wet behind the ears journalist to do some stories about it in the popular media then fold the company up in 3 years time and go and live in Monaco.

Well, there’s a new project to work on I guess.

dv said:

Why silicon? It’s expensive.

The answer for potential investors on the website is “Silicon has extremely high energy density due to the latent heat properties. The high melting point also allows for high efficiency energy recovery. Silicon is also abundantly available, ensuring the technology is sustainable and affordable. It is also non-toxic and completely recyclable.”

Have to admit I didn’t know silicon was expensive. Second most abundant element in the Earths crust and all that. I can’t find info about how pure it needs to be for this system. Maybe it’s enough just to shovel beach sand in to vessel and melt that /s :)

They seem to think the silicon will last decades without needing replaced so maybe it ends up being pretty cheap over all.

esselte said:

Have to admit I didn’t know silicon was expensive.

Nothing to be ashamed of. I’m sure there are still things I don’t know.

I can’t find info about how pure it needs to be for this system. Maybe it’s enough just to shovel beach sand in to vessel and melt that /s :)

Well, melting beach sand won’t give you silicon, it will give you melted silica …

Wresting silicon from oxygen requires a surprising amount of energy and purifying it is expensive as balls. But yeah it does depend on the required purity. 99.9% would be ~ $100000 per tonne, 99.999% more like $500000 per tonne. And to store a significant amount of heat in the context of a major power plant you’ll need a lot of tonnes. It just seems like you could find some material that could store heat pretty well and only cost a few hundred dollars a tonne…

you would have thought silicon would be as cheap as chips.

dv said:

esselte said:

Have to admit I didn’t know silicon was expensive.

Nothing to be ashamed of. I’m sure there are still things I don’t know.

I can’t find info about how pure it needs to be for this system. Maybe it’s enough just to shovel beach sand in to vessel and melt that /s :)

Well, melting beach sand won’t give you silicon, it will give you melted silica …

Wresting silicon from oxygen requires a surprising amount of energy and purifying it is expensive as balls. But yeah it does depend on the required purity. 99.9% would be ~ $100000 per tonne, 99.999% more like $500000 per tonne. And to store a significant amount of heat in the context of a major power plant you’ll need a lot of tonnes. It just seems like you could find some material that could store heat pretty well and only cost a few hundred dollars a tonne…

Bottled water?

Sorry, that’s no good, still several $1000 per tonne.

dv said:

esselte said:

Have to admit I didn’t know silicon was expensive.

Nothing to be ashamed of. I’m sure there are still things I don’t know.

I can’t find info about how pure it needs to be for this system. Maybe it’s enough just to shovel beach sand in to vessel and melt that /s :)

Well, melting beach sand won’t give you silicon, it will give you melted silica …

Wresting silicon from oxygen requires a surprising amount of energy and purifying it is expensive as balls. But yeah it does depend on the required purity. 99.9% would be ~ $100000 per tonne, 99.999% more like $500000 per tonne. And to store a significant amount of heat in the context of a major power plant you’ll need a lot of tonnes. It just seems like you could find some material that could store heat pretty well and only cost a few hundred dollars a tonne…

Makes the cake moulds good value.

AwesomeO said:

dv said:

esselte said:

Have to admit I didn’t know silicon was expensive.

Nothing to be ashamed of. I’m sure there are still things I don’t know.

I can’t find info about how pure it needs to be for this system. Maybe it’s enough just to shovel beach sand in to vessel and melt that /s :)

Well, melting beach sand won’t give you silicon, it will give you melted silica …

Wresting silicon from oxygen requires a surprising amount of energy and purifying it is expensive as balls. But yeah it does depend on the required purity. 99.9% would be ~ $100000 per tonne, 99.999% more like $500000 per tonne. And to store a significant amount of heat in the context of a major power plant you’ll need a lot of tonnes. It just seems like you could find some material that could store heat pretty well and only cost a few hundred dollars a tonne…

Makes the cake moulds good value.

that has an e.

JudgeMental said:

you would have thought silicon would be as cheap as chips.

ha ha

dv said:

JudgeMental said:

you would have thought silicon would be as cheap as chips.

ha ha

Do not encourage him.

From what little I’ve hard about the Spanish facility, its main value is in obtaining ultra high temperatures without chemical contamination.