If the electricity is free, efficiency does not matter that much. The capex of the storage system might matter a lot more. In which case, heating up a big mass might be more economically feasible than battery installations.
> The purpose of Standard Thermal is to make energy from solar PV available 24/7/365 at a price that is competitive with US natural gas.
They compare to natural gas. Not the cheapest alternative.
>Pipes run through the pile, and fluid flowing through them removes heat to supply the customer
Just basic district level geothermal heat pumps do the same. You don't need to heat the soil. Just drill down and install pipes. Earth generates heat. What is the cost difference now?
They skipped a few real competitors that'll shrink their market:
1. In places with underground water reservoirs, these can be used for heat storage very similar to this. It's location dependant but I think there's European district heating networks doing this already.
2. Heat pumps for process steam are gaining ground. The temperature at which heat pumps lose competitivness is slowly rising over time. They mention storage at 600C. Heat pumps win under 80C and are up to 160C and aiming for 200C though at those temps cheap gas will probably win for now. Heat pumps can also recycle process heat and cool and heat at the same time.
3. Wind doesn't get mentioned. Wind doesn't pair as neatly with batteries as solar does but in places with seasonal storage issues the batteries can be used for solar and wind during summer and wind plus whatever (biogas/nuclear/hydro) in winter. They need to worry about both centralised big batteries and customer sited ones.
In general I'm supportive of the idea, but similar to the Nordic sand battery, when they start talking about generating electricity from the stored heat I take that as a signal that they've realised the alternatives above combine to really squeeze the market they have left and undermines my faith in the rest of the product.
Yeah, Form Energy exists to basically disprove this:
Batteries will still be too expensive to arbitrage these seasonal differences effectively. Thermal electricity storage is orders of magnitude cheaper for storage, but worse at daily cycling
Form, like the authors, agrees that Lithium-ion is great for intra-day cycling and not suitable for is seasonal storage. Unlike the authors, Form believes it can engineer chemical storage with the requisite properties. Form’s batteries have something like 10 days of capacity relative to the size of their inverters.
Energy storage yes, electricity storage no. Very limited utility and questionable use of solar PV, which has about a 20% conversion efficiency of solar energy to electricity. Seems like a lot of extra steps to make heat.
One of the biggest uses of residential energy is heating/cooling. Especially in winter months where PV generation is significantly lower (I have seen numbers of 2-5x summer generation), having "free" heat could be quite valuable.
Now, do the economics shake out for storing heat to deliver in winter? No idea, but the idea is not far fetched. Outside of bitcoin mining, there are few uses which can soak up the increasing glut of midday PV generation. Anything that can seasonally store that (even at terrible efficiencies) is valuable. What is going to be the most economic option? No idea. My personal bet is iron-air batteries, but there are a lot of contenders in the space that are competing for widespread adoption.
Absolutely superb. The 'hot bricks in a box' concept of very high temperature thermal energy storage has been really coming into its own with the fall of solar PV costs, and it's quite suitable for industrial consumers of medium temperature heat. There's also a heated granite storage silo in Scandinavia that's recently gone into operation. The rate of heat transfer in the heat storage material is a classic constraint.
I think this niche of 'very long duration, very constant slow rate of discharge' is clever, and it would suit industrial heat consumers but could also suit district heating for buildings in a climate that's predictably in need of heating all winter long (Canada for example).
They seem to have a decent grasp of the fundamentals, both of the technology and how to commercially carve a niche. I wish them well, and thank you for the post.
This is confusing, why PV to heat the dirt? Black paint will do it from sunlight directly. Or circulating hot liquid. Way cheaper and more efficient than PV at collecting heat from the sun.
late to the game, there are villiage/town scale thermal batteries operating in northern scandinavia useing sand inside a conventinal style insulated silos, everything is off the shelf civil engineering equipment.
any company offering similar tech will need a sharp pencil.
I live off grid and am considering adding thermal storage as part of my system to allow for unatended background heating while on the road in the winter, where 2500 liters of water will provide pre heat for domestic hot water, and as a semi passive thermal siphon for area heating
I've done a lot of spreadsheets on this kind of solution, but on a slightly smaller scale: a single family home. While it will work for a while it is not enough to meaningfully offset the seasonal cycle which is the thing that needs solving. Storing energy for a few days up to two weeks is (relatively) easy, storing it cheaply for up to 6 months is very hard unless you are willing to invest massively offsetting much of your savings. The pile of rock required to heat an average home for a couple of weeks handily outweighs the house itself. And that's without a double conversion, it is used and stays as heat, the idea was to moderate the leakage upwards as a source of heat by blowing air in a controlled manner rather than to convert it again.
So I really hope these guys will succeed where I can't even get it to work on paper, sometimes scale really is a requirement to make something work and this could very well be one of those.
I've found that lots of people get viscerally mad when it's pointed out that solar pv is not reliable year long and that the batteries to make it seasonally reliable are wildly expensive.
I wonder if they have had issues trying to solve a problem so many people insist doesn't exist.
I have a home in the southwest that is off grid and runs on solar plus lifepo3 batteries. It has been 5+ years now. My cost per kwh is below $0.008 as of today including all capital and maintenance. These numbers get a bit complicated, for example I run the AC much colder than I would if I was paying more for it. I have extra fridges and freezers I probably wouldn't if I had to pay higher per kwh. I "throw away" a lot of power too that I am not counting when the batteries fill up.
I have about 40kwh of storage. The batteries are in steel boxes and there are some basic precautions to take with them but lifepo3 has a very manageable risk profile quite different from lipo. Batteries and solar equipment continue to get cheaper, the same system I have is now 50% cheaper today then when I bought it, including tariffs.
The link really discusses more of a single neighborhood or medium industrial site possible type of technology. Really just a huge very hot pile of sand and steam turbine or propane cell generation. On a kwh basis it is probably not competitive with solar+battery unless your use case involved a lot of direct use of hot water or heating something.
You're pretty close to the ideal location for solar + batteries. For much of Europe or the Eastern US, this amount of storage would be nowhere close to enough, by orders of magnitude - they need to make it through the winter, and generate heat from it, after all.
For each location, there's an ideal amount of storage and an ideal amount of overbuilt capacity, both depending on hardware costs (and contributions of wind to the energy mix).
In your case, both numbers are relatively small. With lower incident sun, persistent cloud cover, and the possibility of becalmed wind turbines, storage requirements can start to make thermal batteries or hydrogen storage economical.
The US National Renewable Energy Laboratory was working on energy storage involving a silo of hot sand.[1] But that was probably cut by the Trump Administration.[2]
The sand scheme involves putting hot sand into the top of the silo, and draining out sand into a heat exchanger at the bottom. So you can have more storage than you have heat exchanger capacity. The "ultra cheap" approach in the article requires resistance heaters and plumbing all through the cheap dirt.
Molten salt has also been used for this, successfully.
I wonder if any heat pumps can emit the 600C they target for the storage mounds. If the COP of such a device was over 1, they could store more heat energy than the PV’s emit in wattage.
Also, they could use the waste cold air to cool the solar panels, which increases their efficiency.
Snow load is not mentioned when using horizontal panels. In higher latitudes, solar is relatively uncommon because of the sunlight deficit in winter. Panels that are deployed are usually placed at an incline equal to the latitude (or even vertically) to capitalize on free snow shedding and to regularize/maximize year-round minimum output (i.e. bring up winter by bringing down summer). Mounting solar panels flat is sensible from the standpoint of this technology (no solar output needed in the winter, that's what the storage is for!) but may be breaking a lot of ground (and panels) with horizontal panels in snow country.
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[ 2.6 ms ] story [ 47.2 ms ] threadCutting out the conversion steps should be more efficient.
They compare to natural gas. Not the cheapest alternative.
>Pipes run through the pile, and fluid flowing through them removes heat to supply the customer
Just basic district level geothermal heat pumps do the same. You don't need to heat the soil. Just drill down and install pipes. Earth generates heat. What is the cost difference now?
This doesn't with everywhere though? Because of geology?
1. In places with underground water reservoirs, these can be used for heat storage very similar to this. It's location dependant but I think there's European district heating networks doing this already.
2. Heat pumps for process steam are gaining ground. The temperature at which heat pumps lose competitivness is slowly rising over time. They mention storage at 600C. Heat pumps win under 80C and are up to 160C and aiming for 200C though at those temps cheap gas will probably win for now. Heat pumps can also recycle process heat and cool and heat at the same time.
3. Wind doesn't get mentioned. Wind doesn't pair as neatly with batteries as solar does but in places with seasonal storage issues the batteries can be used for solar and wind during summer and wind plus whatever (biogas/nuclear/hydro) in winter. They need to worry about both centralised big batteries and customer sited ones.
In general I'm supportive of the idea, but similar to the Nordic sand battery, when they start talking about generating electricity from the stored heat I take that as a signal that they've realised the alternatives above combine to really squeeze the market they have left and undermines my faith in the rest of the product.
Now, do the economics shake out for storing heat to deliver in winter? No idea, but the idea is not far fetched. Outside of bitcoin mining, there are few uses which can soak up the increasing glut of midday PV generation. Anything that can seasonally store that (even at terrible efficiencies) is valuable. What is going to be the most economic option? No idea. My personal bet is iron-air batteries, but there are a lot of contenders in the space that are competing for widespread adoption.
I think this niche of 'very long duration, very constant slow rate of discharge' is clever, and it would suit industrial heat consumers but could also suit district heating for buildings in a climate that's predictably in need of heating all winter long (Canada for example).
They seem to have a decent grasp of the fundamentals, both of the technology and how to commercially carve a niche. I wish them well, and thank you for the post.
So I really hope these guys will succeed where I can't even get it to work on paper, sometimes scale really is a requirement to make something work and this could very well be one of those.
Why didn’t this submission redirect to mine?
I wonder if they have had issues trying to solve a problem so many people insist doesn't exist.
I have about 40kwh of storage. The batteries are in steel boxes and there are some basic precautions to take with them but lifepo3 has a very manageable risk profile quite different from lipo. Batteries and solar equipment continue to get cheaper, the same system I have is now 50% cheaper today then when I bought it, including tariffs.
The link really discusses more of a single neighborhood or medium industrial site possible type of technology. Really just a huge very hot pile of sand and steam turbine or propane cell generation. On a kwh basis it is probably not competitive with solar+battery unless your use case involved a lot of direct use of hot water or heating something.
> I have about 40kwh of storage
You're pretty close to the ideal location for solar + batteries. For much of Europe or the Eastern US, this amount of storage would be nowhere close to enough, by orders of magnitude - they need to make it through the winter, and generate heat from it, after all.
For each location, there's an ideal amount of storage and an ideal amount of overbuilt capacity, both depending on hardware costs (and contributions of wind to the energy mix).
In your case, both numbers are relatively small. With lower incident sun, persistent cloud cover, and the possibility of becalmed wind turbines, storage requirements can start to make thermal batteries or hydrogen storage economical.
The sand scheme involves putting hot sand into the top of the silo, and draining out sand into a heat exchanger at the bottom. So you can have more storage than you have heat exchanger capacity. The "ultra cheap" approach in the article requires resistance heaters and plumbing all through the cheap dirt.
Molten salt has also been used for this, successfully.
[1] https://www.solarpaces.org/nrel-results-support-cheap-long-d...
[2] https://www.wenatcheeworld.com/news/northwest/trump-congress...
Also, they could use the waste cold air to cool the solar panels, which increases their efficiency.
LNG is standardized, it's readily available, and existing infrastructure already exists.
how is this new system better?