Electrically conductive bricks can replace fossil fuels in industrial processes
bostonglobe.comIf these systems have enough thermal mass then maybe you could even power them with solar or daily offset cheaper power in another storage mechanism.
Between this and the newer co2 reduction technologies in kilns we might be close to finding ways to build combined steel and cement factories that have massively reduced greenhouse gas emissions.
That's just inefficient solar thermal though.
If you want to do that you'd be better off using parabolic mirrors to heat regular fire bricks directly.
These are unique it seems because they're durable electric heating elements that can hit industrial process temperatures and might be cheaper then alternatives?
Well like you said the resistive heating is what sets it apart, and still makes it potentially useful as a thermal ESS because of the classic duck curve even if it's not the primary use case. Soak up excess elec during midday as heat in batteries, use TPV to convert IR back to elec during evening peak or outages. Antora (eg) does this with carbon blocks in shipping container sized units. Would be more desirable/flexible to do a setup like that where the TESS is just another prosumer on the electrical grid rather than using parabolic mirrors+firebricks which can't be used for time delaying supply. Can't speak to the pros/cons of this vs carbon block thermal batteries but still a potential avenue.
It requires full sun to hit steal melting temperatures which is unreliable in many industrial areas. So you need a backup.
You can also easily move electrical power long distances but parabolic mirrors are hard to integrate into existing industrial processes and locations. PV electricity is competitive with fossil fuels even if you ultimately just want heat.
Solar thermal is far more viable for low grade heat. Especially as energy storage is fairly trivial.
This comment isnt about the industrial processing applications of this technology, but energy storage.
How exactly are you going to CHEAPLY collect and store energy for a 1400+C process using solar thermal?
It seems like an huge advantage to use an 80% thermal setup vs a 22% efficient panel, but we gave up on solar power towers for a bunch of reasons. With PV things are a lot more straightforward because you can reach nearly any temperature at equal efficiency.
Maybe I dont understand. If your primary goal is thermal storage, why do you care about the peak temperature?
If we are talking primarily about storage, what are the advantages of a PV field + 1400 C brick storage vs parabolic + 500C storage?
> If your primary goal is thermal storage
The goal isn’t thermal storage the goal is to do something that needs extreme temperature.
You can’t melt steel at 500C, you can melt it in bricks at 1500C that then cool to 1400C. Use electricity to heat a brick to 1500C and you get 100C worth of energy storage. Use solar thermal to get to 1400C and you get zero energy storage.
I think that is kinda my point. These comments are all in reference to the idea of using these bricks for electrical storage, as an alternative of offset to other technologies like molten salts, batteries, or pumped hydro.
Im skeptical that they would be improvement on other forms of grid power storage.
This is independent of the question if they are good for melting steel.
I guess I dont understand the point you are advocating for.
The energy never gets turned back to electricity. It’s electricity > melting iron for steel (or whatever) and we’re inserting an energy storage in the middle because it’s effectively free.
The total energy storage is also unlikely to be huge so it’s more like load management not really grid storage. https://en.wikipedia.org/wiki/Load_management IE: Because we have energy storage and other users don’t we can cut demand when prices spike. Utilities will cut special rates for companies that allow the utility to load shed them first.
The same basic concept is common in other areas. Get enough storage for ~free such as with an EV and you can simply wait until prices get cheap before charging.
Higher temperaure = more energy stored in the same material. Simple as that. When you have a process requiring 400C for reasonable effiency, your storage actually starts to count from above 400C, so if you have 500C storage, you only have effectively 100C of usable tmperature difference stored in your bricks.
If it is cheaper to store at 1400 than 500, then that is an argument for doing so. Higher temperature is not a justification in its own right, absent economic benefit. It is also the case that conduction losses are proportional to heat, and it brings many other challenges as well.
Chemical processes don’t occur at any temperature. So the ideal storage temperature depends on the goal temperature and a bunch of other factors.
The argument for storing at 1500C could be 500C is useless not just worse economically.
The parent correctly notes that you can't use solar thermal directly for industrial processes because it won't get hot enough and that it's easier to retrofit electric infrastructure than a bunch of mirrors and optics.
Grandparent:
> These are unique it seems because they're durable electric heating elements that can hit industrial process temperatures and might be cheaper then alternatives?
Storage usually makes less sense, but depends on capital cost per kW-hr right? No idea on the economics of that, but an electric heater can get hotter than solar thermal and use much less space at the point of use.
They are durable electric heating elements that can get hotter than solar thermal and hit industrial temperatures without using fossil fuels to heat locally with fire.
I understand what they are. I am skeptical that they more economical than other forms of grid power storage.
IF you just want to go electricity>heat>electricity Industrial Arc furnaces can go to 2000 C (and much higher but they have no industrial need).
I would love to be wrong.
> IF you just want to go electricity>heat>electricity
I think the idea here is to go electricity->heat-storage->heat-usage, using the heat storage to take advantage of cheap renewables that might be otherwise curtailed and to buffer the heat to provide reliability for whatever process it is used for.
Almost any form of energy storage other than heat (i.e. batteries, hydrogen, gravity) would be far more expensive in that use case. By comparison, bricks are an incredibly cheap way to store heat.
If packaged correctly this could also be useful for uses like ovens at industrial bakeries, which have highly predictable energy use patterns.
Thanks, I understand better. I'm sure there are some applications for pre-heating to time shift demand, but I do think it is limited.
> I'm sure there are some applications for pre-heating to time shift demand, but I do think it is limited.
Another example of a big application for time-shifted heating is domestic hot water heating with heat pump water heaters (or even resistance water heaters if the electricity is cheap enough). At least one company (https://www.harvest-thermal.com/) is taking this further to also provide space heating by time-shifting heat, again using water as the energy storage technology.
Solar thermal requires lots of pipes that you pump molten salt and/or steam through, it's far more expensive than PV. The efficiency doesn't matter as much as the cost, unless you're limited by land to build grid PV on.
There are no moving parts in PV or these bricks, which means they'll have near-zero maintenance costs.
Also I'm pretty sure solar thermal can't heat steel - it relies on steel pipes throughout the entire system.
They don’t even necessarily need to be cheaper than all existing methods. They only need to be cheaper than (IMO inevitable) carbon tax penalties plus the cost of these bricks compared to current methods, which is a rapidly falling curve.
>They don’t even necessarily need to be cheaper than all existing methods.
That doesn't make sense. Why would anyone use them instead of the more efficient alternatives? For artistic reasons?
you omitted the immediately following sentence...
>They only need to be cheaper than (IMO inevitable) carbon tax penalties plus the cost of these bricks compared to current methods, which is a rapidly falling curve.
this clearly indicates OP suggests they will become de facto cheaper once the traditionally externalized costs of environmental impact are accounted for.
The alternatives are also carbon free, which is the point of the parent post.
The comparison is between this and carbon free solar-thermal for energy storage. Saying it doesnt have to be cheaper than solar-thermal simply isnt true.
Fair fair. Unlike traditional solar thermal though, this can just function as regular node on the electric grid (or even a prosumer) so it is decoupled from the attendant variability. As such they are not quite comparable IMO.
It should be enough to be cheaper if you include the environmental cost that fossil fuels cause to society and planet.
Solar thermal energy storage isnt fossil fuels and carries no major environmental cost.
Neat idea. I'm usually skeptical (cynical?) when news outlets write advertorials for world-changing startups, but I'm gonna keep an eye on these guys.
Very clever!
Wondering why archive.is is ok to replicate articles beyond paywalls while chatGPT got sued for a few unintentional regurgitations. Should there be a "protect it or lose it" rule for copyright as in trademarks?
I'm not sure if archive.is leverages this (I doubt it has a huge database of paid accounts) but a lot of sites put up full content versions of their sites so search engines can scrape them, so there may be some legal shimmying about taking that search engine version and making it available to regular human eyeballs.
Who said Archive is OK with publishers? They are just based in Russia and give the middle finger to anyone who tries to sue them.
How does this fit into the wider picture of steelmaking with electric arc furnaces? Those have been around for a good long while; what can this do that an electric arc furnace can't?
Pretty much nothing, at least for steel. You still need the carbon to incorporate into the alloy so like arc furnaces, they can only be used with mostly scrap material. That’s why steel makers still use coal. They need the coke.
IIRC steelmakers use roughly 2 parts iron to 1 part coke, which means coke would be 33% of the weight, but steel is only 1% carbon - that's an efficiency of only 3%. Metallurgical coal is used primarily because it burns hot enough to efficiently melt iron.
> Metallurgical coal is used primarily because it burns hot enough to efficiently melt iron.
That’s the historical reason, but now it's used because carbon is a reducing agent that binds to oxygen, preventing it from oxidizing the iron back into iron oxide and because the coke is used as a permeable membrane to let the resulting gasses escape.
If it was just a matter of heat, there's any number of cleaner fuels steelmakers could use but they can't because the coal serves an important role in the chemistry of blast furnaces.
Thanks, was going to ask where the carbon was coming from
Electric furnaces introduce carbon using graphite electrodes which is enough for the carbon that gets embedded in the alloy but to convert the iron oxide in raw ore to pure iron in a blast furnace, you need a lot more carbon as a reducing agent to bind to oxygen, preventing it from oxidizing the working material as the metal cools. The coke also serves a dual purpose as a semi-permeable solid that allows the hot gasses to escape from the furnace without collapsing under the weight of the molten metal.
Neat. We need more "box of hot rocks" thermal storage solutions.
It's fun to compare and contrast strategies, as startups explore and define the problem space.
For example:
Fourth Power is a heat to electricity solution. It uses graphite bricks (up to 2400°C), liquid metal for plumbing, and thermophotovoltaic cells.
https://gofourth.com/our-technology/
Electrified Thermal Solutions is an electricity to heat solution. It combines the heating element, storage, and exchanger into a single brick (up to 1800°C).
This is an article about Electrified Thermal Solutions.
antora also is a promising thermal pv company - heat up some carbon blocks resistively when clean power supply exceeds demand, then convert back to elec during peak demand or outages via pv panels operating on IR. Hopping container form factor. interesting partnerships w NREL and other gov partners.
I can't say I've ever really thought about using electricity to generate high heats because it's often way less efficient (convert x -> electricity -> heat, vs just chemical(combustion) -> heat) But sure, if you had "free" electricity (wind/solar) that is less of an issue.
I'm wondering if anyone has done the math for a cement plant in the southwest surrounded by PV solar.
This is incredibly wasteful and will end up being a net-negative for greenhouse gas emissions by crowding out other, more efficient uses of that electricity besides heating things up. One of the first things they teach you in engineering thermodynamics is that electricity is very high quality energy compared to process heat, and that you can do a lot more useful things with electricity such as powering motors or electronics. Electricity generation typically results in lots of waste heat, which you would be far better off recycling into process heat through cogeneration instead of what this article is doing, which is throwing away process heat to convert electricity into even more process heat.
> Electricity generation typically results in lots of waste heat
Typically, but may no longer be true with renewables. I don't think any of solar pv, wind, and hydro generates significant heat in the process of their power generation.
The patent [1] has more details if anyone is interested.
Yeah, this is why I’m not too worried about the energy storage side of going 100% renewable energy in a scenario where we also decarbonise completely.
Storing energy as heat is dead simple, cheap, can let you store huge amounts of energy, and you can store for fairly long timespans.
It doesn’t matter that you can’t feed power back to the grid (well, maybe you can.. you can convert the light given off the heated block with photovoltaics.. but that won’t be a huge factor). If we decarbonise industrial heat it will create enough demand for renewables that the minimum output of renewables (over a larger area, I think it’s fair to assume some grid improvements over the next years) will be more than enough to cover base load needs. We will probably have quite a lot of batteries for frequency regulation and smoothing out the duck curve. Some of that will also help with dunkelflaute. But mainly there will just be so much renewables that the output never goes below what is needed on a given day.
There’s so many aspects of decarbonisation that makes balancing the grid easier. Electric cars is another example, where a lot of people will have flexibility of delaying or being proactive with charging based on electricity price forecasts. I expect most rental car companies will provide some grid balancing services, and in the near future you’ll have to pay extra to check out a car with 100% SoC.
> It doesn’t matter that you can’t feed power back to the grid (well, maybe you can.. you can convert the light given off the heated block with photovoltaics.. but that won’t be a huge factor).
FWIW there are a few other comments in this page discussing TPV (albeit briefly) and there are at least a few companies seriously pursuing it with federal support. It is a pretty interesting alternative to other forms ESS, particularly for long duration (ie more relevant for critical resiliency applications than supply/demand arbitrage). Like you said probably will not end up super relevant in the grand scheme of the grid’s total ESS capacity, but it will most likely have a niche I think.
> I expect most rental car companies will provide some grid balancing services, and in the near future you’ll have to pay extra to check out a car with 100% SoC.
Rental car companies are an interesting example I hadn’t thought of before - thanks for highlighting that. Another more common challenge/opportunitu will be campuses - eg universities, large corporations, etc which have their own microgrid (often a CHP/district system in the northeast at least) - which may have a large number of commuters arriving in the morning and potentially wanting to charge their EVs all day. In 15 years, this might represent a pretty significant increase in demand, and represents giving a pretty substantial amount of free electricity to commuters (if things stayed as they are today). At the same time, charging up all of those vehicles during midday and then sending them home to immediately discharge when they plug in at 5-7pm could substantially abate the duck curve, and being an even larger further savings for the commuter. Seems obvious that some sort of new agreements/contracts etc will come in to play for these sorts of campuses.
I wonder how useful this would be in space. Say, some sort of smelter or furnace on the moon. Fossil fuels are hard to come by there, whereas you could probably set up a fairly large solar farm relatively cheaply.
But how efficient is it? I don't see that info in the article.
Well it is just a brick that can acts as a heating element. In terms of converting electricity to heat it is almost 100% efficient like every other electric heating element.
I didn't spot any mention of voltage requirements for that so maybe it requires so high voltage that cause it to be a bit harder to actually use.
Agreeing with the above, also relevant:
- Heat pumps typically achieve better than 100% efficiency, though at modest temperatures (slightly above ambient room temperatures), and would be better suited to most space-heating applications.
- The key achievement of the described technology is very high temperature applications, such as metals smelting, though what advantages the described tech has over existing electric arc furnaces (utilising graphite electrodes, cheap and abundant and capable of 3,000 °C temps) is less than clear.
> In terms of converting electricity to heat it is almost 100% efficient like every other electric heating element.
except there are many types of heat pump in this world that routinely achieve well above 100% efficiency, since pumping heat from a cold heat bath to a hot one can cost significantly less energy than generating that heat resistively.
That is not in any way related to the theoretical efficiency of resistance heating and not really of any help here unless there is some working fluid which allows for the temperatures needed for industrial processes. It might be possible to recuperate process heat if a suitable working fluid can be found which evaporates at the temperature of the product leaving the process chamber and condenses at a temperature suitable for (pre-)heating the process chamber. I have not heard of such though.
Heat pumps are not heating elements.
Yeah except heat pumps are really not very efficient at high temperature differentials. They are great if the outside temp is 5 deg C to bring it to a nice comfy 20 deg C. They would not work very well if you want to brung the temperature to thousands of degrees C.
Don't get me wrong, it would be super cool if someone creates a heat pump that can bring the temperature up enough to melt iron ore at greater than 100 percent efficiency, but it does not seem like anyone currently making heat pumps considers this remotely possible.
They're not very conductive if they're getting 1800 degees hot when you pass current through them.
Every material is a conductor in a high enough potential! And if you pass enough current through copper, it can get to the same temperature, provided you're careful enough to maintain contact after it melts.
The distinguishing feature to call these "conductive" is that you could make a kiln of these bricks and ordinary bricks, and the current should preferentially pass through the conductive ones. Some of the current will leak through every other available path, including the air, but that's true of every circuit in existence. Vacuum isn't supposed to conduct, but vacuum tubes pass current through it, don't they?
> And if you pass enough current through copper
Yeah, but how do you make a copper wire heat up without also heating up the wiring that leads to that copper wire? You can make it thinner, but these bricks aren't very thin.
Induce a current magnetically and you don’t need a direct wire connection. As for what to put in the intervening space I will leave that as an exercise.
Induction cooktops are ridiculously efficient at heating
Nice idea, but for generating that magnetic field you propose to use ... electric current? ;)
Responding to your question two above:
You've probably seen multiple instances of this in your daily experience. A fuse is a thin conductor between thick electrodes. A light bulb is a very fine conductor between thick electrodes, encapsulated in a vacuum bulb. If you use tungsten electrodes, you can easily melt copper in the manner I've described -- that's how TIG welders work.
Responding to your question about electric current:
Quite simply, use leverage! Take a transformer with multiple (N) windings on the primary and a single winding on the secondary. Putting one (DC) amp through the primary will induce N amps through the secondary. With induction, you can use a low current to induce high current. Or correspondingly, transform low (AC) voltage to high voltage -- this is how high voltage power lines work.
True, but something should be there to close the loop on that not-so-thin brick, and that something will get hot. That picture shows only a single brick, not a loop of bricks so something does not add up.
The picture shows glowing hot electrodes; are you being deliberately obtuse?
You stick a large high temperature electrode into molten copper. This is how an arc furnace works. Some have water cooled electrodes to keep them from melting.
There is a difference between thermal conductivity and electrical conductivity of a material. They have low electric conductivity, so when you try to pass a current through them, they get hot. They are thermally conductive, so the heat spreads around the brick quickly.
They're gonna hit an Ohm run with this one.