Iron fuel energy storage (to support renewables)

louis · 2020-01-14 08:45:52

Very interesting new approach to creating an energy storage system that can work with renewables:

https://www.youtube.com/watch?v=N5iTxoHOdBY

The system uses iron powder as a fuel to work with air, in providing energy and generating electricity via combustion when wind/solar are deficient.

The used fuel, iron rust, is then recycled (via the application of renewables energy) to make more iron powder.

Ingenious!

It could work on Mars of of course, where there is plenty of iron at the surface, but it would be necessary to provide the oxygen supply, so a further step would be electrolysis of water. It might possibly be a simpler means of storage compared with methane manufacture and storage.

tahanson43206 · 2020-01-14 12:25:01

For Louis re #1

Another impressive find!

SearchTerm:IronStorage
SearchTerm:IronEnergyStorage

This system could be put to use on land immediately.

An advantage that comes to mind is that this system could be used in place of coal. The railroads and all their equipment could be adapted easily to this material, and all the jobs that go with that activity could be saved. Coal burning power plants across the US, and around the world could be saved, and all the jobs associated with them could be saved.

All that said, this is a laboratory demonstration.

Folks with deep pockets are needed to take it and build the infrastructure needed.

There are folks in the forum who can comment upon the efficiency of the various stages of the process.

It would be useful to be able to compare the efficiencies of a coal burning power plant of today with the proposed iron powder version.

A significant cost benefit would be NOT having to scrub the output gases as must be done with coal today.

(th)

Last edited by tahanson43206 (2020-01-28 13:19:02)

SpaceNut · 2020-01-14 18:09:17

In a free energy utopia its storage is as great as the amount of the planet but we know that there is no free ride and that in actuality its a losing battle. The lose of reduction us due to impurity, thermal and in isotope change. Coal is full of impurities.

louis · 2020-01-14 18:39:19

I expect a cost disadvantage is that you have to purify and then mill iron into powder form...But, yes, even if it is more costly than coal, it could still work well with renewables energy if you are using the surplus energy (with a marginal price of virtually zero) to prepare the iron and then recycle it after use... The economics on Earth certainly need investigating. But it might make sense on Mars, since storing iron powder sounds to me far less labour intensive than storing methane. However in both cases we would still need to store oxygen (or some type of oxygen-rich gas compound equivalent to air).

tahanson43206 wrote:

For Louis re #1
Another impressive find!
This system could be put to use on land immediately.
An advantage that comes to mind is that this system could be used in place of coal. The railroads and all their equipment could be adapted easily to this material, and all the jobs that go with that activity could be saved. Coal burning power plants across the US, and around the world could be saved, and all the jobs associated with them could be saved.
All that said, this is a laboratory demonstration.
Folks with deep pockets are needed to take it and build the infrastructure needed.
There are folks in the forum who can comment upon the efficiency of the various stages of the process.
It would be useful to be able to compare the efficiencies of a coal burning power plant of today with the proposed iron powder version.
A significant cost benefit would be NOT having to scrub the output gases as must be done with coal today.
(th)

Calliban · 2020-01-15 06:23:30

You use huge amounts of high grade electricity to make iron, with significant energy losses. You then burn it in a boiler to produce electricity, with most of the embodied energy being lost as waste heat. What's more, the reduction furnace will sit idle much of the time and the refractory lining will cool and develop stress fractures.

If you are going to make iron, I think it more likely that you would want it to be part of a continuous steady-flow process. It is also most valuable as an end product in itself for structural engineering purposes. It makes no sense burning it.

tahanson43206 · 2020-01-15 07:59:31

For Calliban re #5

As I read the original report, the proposal is to use iron as an energy carrier. Once refined, the powder would be used over and over again, with no (or little) additional investment beyond converting it back from rust to clean powder.

What would be helpful for understanding, if you have the time, would be to see realistic efficiency figures for this particular energy carrier, as compared (for example) to pure hydrogen.

My expectation is that hydrogen is more efficient overall, but I could be mistaken, because there are so many losses in the production, distribution and use of hydrogen.

Another well known energy carrier is methane, which can be manufactured using wind or solar energy (or nuclear for that matter).

A useful output of this discussion would be a realistic comparison of end-to-end use of these three energy carriers.

I would be quite surprised if iron does NOT come out looking pretty good.

That would apply particularly if the application for which iron is chosen as the energy storage medium is heating primarily, with electricity generation a sideline.

I do NOT disagree with you about nuclear power. I have said on multiple occasions in this forum and elsewhere that if this civilization wants to rise above Level Zero where we are now, we HAVE to master our own weaknesses, so that we can use nuclear power abundantly and safely.

There is a big IF in that statement. There are likely to be plenty of people who do NOT want to rise above Level Zero.

(th)

Last edited by tahanson43206 (2020-01-15 08:02:14)

Calliban · 2020-01-15 10:04:43

Wiki lists the energy density of Iron as 5.2MJ/kg, assuming it is burned to Iron (III) oxide.
https://en.wikipedia.org/wiki/Energy_density

The embodied energy of mild steel, which is basically pure iron, is 20.1MJ/kg. But even that assumes that most steel is recycled in electric furnaces. If you have to reduce iron from iron oxide, embodied energy is closer to 30MJ/kg. You will need hydrogen to do this, as you need a reducing agent to strip away the oxygen.
https://en.wikipedia.org/wiki/Embodied_energy

Straight off, you have lost over 80% of the energy you started with, which is high grade electricity. At smaller scales (blast furnaces are huge), thermal losses would reduce efficiency even further.

To recover energy, you must burn the iron within a boiler. The solid lumps will oxidise as they fall and radiate heat to the boiler walls, where you would presumably raise high pressure steam that is used to generate electric power. That process is 25-45% efficient, depending on scale, steam temperatures and pressures.

So, overall efficiency is 4.3-7.8%. Not good at all.

We have already discussed synthetic methane/oxygen as an energy storage system, which is about 5-8% efficient. If you are starting with solar power, you would actually do better growing sugar cane in a pressurised greenhouse and burning it in a boiler to raise steam.

Hydrogen (stored in a gasometer arrangement, without liquefaction or heavy compression) is a better option than either of these, but still not a good one. Practical efficiency using commercially available alkaline electrolysis and combined cycle gas turbines, is about 40%. You are still losing 60% of the original energy and storage volume is huge, but nominally the efficiency is higher and the capital equipment is more compact and cheaper than a blast furnace needed to reduce iron. There is a scale dependency. Efficient CCGT units come in sizes of 100-400MWe. Smaller scale systems will be much less efficient and non-standard.

A much cheaper option, assuming heat is desired as an end product, would be to store energy as high quality heat. You could have rock beds or water tanks containing heating elements, that would be switched on when power was abundant and then used for things like metal melting, cooking, hot water, etc. Capital costs are low and storage density is high. The downside here is that for low temperature applications, using electricity to produce heat with heating elements is not a particularly efficient use of exergy, though it probably beats most of the storage options above through its sheer simplicity and low capital cost.

Compressed air (or CO2) is an option, especially is there are advantages involved in using it directly as an energy source for tools, rather than going through the capital intensive intermediate step of converting it back into electricity. But there are energy losses in compression and pressure vessels are expensive components.

Curtailing demand is potentially the cheapest option in terms of using primary energy with minimal losses. That’s a posh way of saying that we will go without when it isn't there. If it is easy to do that for some processes, that are only carried out intermittently, then it may be the most efficient and cheap thing to do. We don't necessarily need to run a machine shop 24/7, or pump water 24/7. But capital cost amortisation of equipment is not a trivial issue. Controlling energy use at a consumer level is another complication.

A better option all round, would be to start with an energy source that is reliable and produced power when we need it. I can think of one.

Last edited by Calliban (2020-01-15 10:08:49)

louis · 2020-01-15 10:06:28

You can discount the energy costs of making the iron powder and recycling it as waste electricity will be used (ie excess electricity produced by renewables above the level of demand, which would otherwise be earthed). The marginal cost of waste electricity is close to zero. Iron is being made all the time, for purposes other than providing a fuel, so in effect you can switch to the waste electricity as required...in effect I think you would be renting time at the furnace to make your iron. Could be dealt within on an annual basis...e.g. the agreement could be that you get 20% of the iron output per annum and you provide 20% of the energy required (via waste electricity) over the year while making a proportionate payment towards the capital and operating costs of the furnace.

I'm not sure what process is involved in recycling rust exactly - ie does it go back into a furnace? I guess it probably does.

Calliban wrote:

You use huge amounts of high grade electricity to make iron, with significant energy losses. You then burn it in a boiler to produce electricity, with most of the embodied energy being lost as waste heat. What's more, the reduction furnace will sit idle much of the time and the refractory lining will cool and develop stress fractures.
If you are going to make iron, I think it more likely that you would want it to be part of a continuous steady-flow process. It is also most valuable as an end product in itself for structural engineering purposes. It makes no sense burning it.

tahanson43206 · 2020-01-15 10:33:42

For Calliban re #7

Thank you for the kernel of a table of comparative values!

Wiki lists the energy density of Iron as 5.2MJ/kg, assuming it is burned to Iron (III) oxide.
https://en.wikipedia.org/wiki/Energy_density

As I find time I will try to build up a comparison chart for energy carriers: hydrogen, carbon, iron

Edit: The Wikipedia article contained a full list of substances. iron has about 1/10th the energy content per Kg as many familiar carbon fuels.

As I read the original article, I suspect iron is going to come out looking surprisingly attractive in certain situations.

An example that comes readily to mind is the fleet of coal powered electric plants in the region where I live in the US.

Every day, trainloads of coal pass through the town on their way to various electric power plants.

The coal output solids are NOT recycled as iron would be. They accumulate.

The coal cars head back to the coal fields empty.

In the case of an iron-energy-carrier system, the cars would head back to the Texas wind fields full of powered rust.

A spill of powdered rust (or powdered iron) for that matter would be of relatively small consequence, compared to the costs of spills of liquid or gaseous carbon energy carriers.

In the case of carbon based fuels, the carbon goes into the atmosphere. That problem would NOT occur with iron.

(th)

Last edited by tahanson43206 (2020-01-15 20:31:05)

Calliban · 2020-01-15 17:03:37

louis wrote:

You can discount the energy costs of making the iron powder and recycling it as waste electricity will be used (ie excess electricity produced by renewables above the level of demand, which would otherwise be earthed). The marginal cost of waste electricity is close to zero. Iron is being made all the time, for purposes other than providing a fuel, so in effect you can switch to the waste electricity as required...in effect I think you would be renting time at the furnace to make your iron. Could be dealt within on an annual basis...e.g. the agreement could be that you get 20% of the iron output per annum and you provide 20% of the energy required (via waste electricity) over the year while making a proportionate payment towards the capital and operating costs of the furnace.
I'm not sure what process is involved in recycling rust exactly - ie does it go back into a furnace? I guess it probably does.
Calliban wrote:
You use huge amounts of high grade electricity to make iron, with significant energy losses. You then burn it in a boiler to produce electricity, with most of the embodied energy being lost as waste heat. What's more, the reduction furnace will sit idle much of the time and the refractory lining will cool and develop stress fractures.
If you are going to make iron, I think it more likely that you would want it to be part of a continuous steady-flow process. It is also most valuable as an end product in itself for structural engineering purposes. It makes no sense burning it.

Louis I have a business proposition for you. I propose that you send me £10,000 of your excess income each year, in whatever random instalments you like. In return, I will pay you back £780 at whatever time in the year you like. It is excess income, that is over and above what you need to buy food and stay alive. So presumably, it has no value. What's not to like?

Calliban · 2020-01-15 17:17:07

tahanson43206 wrote:

For Calliban re #7
Thank you for the kernel of a table of comparative values!
Wiki lists the energy density of Iron as 5.2MJ/kg, assuming it is burned to Iron (III) oxide.
https://en.wikipedia.org/wiki/Energy_density
As I find time I will try to build up a comparison chart for energy carriers: hydrogen, carbon, iron
As I read the original article, I suspect iron is going to come out looking surprisingly attractive in certain situations.
An example that comes readily to mind is the fleet of coal powered electric plants in the region where I live in the US.
Every day, trainloads of coal pass through the town on their way to various electric power plants.
The coal output solids are NOT recycled as iron would be. They accumulate.
The coal cars head back to the coal fields empty.
In the case of an iron-energy-carrier system, the cars would head back to the Texas wind fields full of powered rust.
A spill of powdered rust (or powdered iron) for that matter would be of relatively small consequence, compared to the costs of spills of liquid or gaseous carbon energy carriers.
(th)

Tahanson, did you read any of the analysis I carried out? If you try and store energy in iron powder you lose over 90% of what you started with. In what universe could that possibly come out looking good? You have to pay for every single unit of electricity that is wasted in this way. None of it is free, because all of it depends upon investment in capital equipment.

When you couple this with a primary energy source that has very high embodied energy in the first place, it ends up looking more and more like an energy sink. If it takes one unit of invested energy in turbines to yield 20 units of harvested energy and you waste 90% of that energy in making iron powder, do you think the system would still be viable as a net energy source? Is there any proportion of that energy that would really be worth wasting in such a way?

The high embodied energy of renewable energy sources makes it less tolerable to waste energy in energy sinks. It is why I find it unlikely that renewable energy sources will ever be deployed with huge amounts of dedicated storage in an electricity-electricity loop. The fact that intermittency is a pain in the ass will not make it any easier to tolerate losing energy in inefficient storage processes. If humanity is foolish enough to keep pouring resources into this boondoggle, then ultimately end uses will need to adapt to efficiently make use of intermittent energy. That means doing energy intensive things when the energy is available and doing low-energy things when it isn't. But even that isn't a cheap way of dealing with intermittency. You have to pay for the equipment that uses the energy. It has its own embodied energy costs. So if you are using equipment intermittently and pushing down its productivity, you are ultimately only transferring the inefficiency from the energy source to the rest of the economy. The second law of thermodynamics has never been cheated and never will be.

Last edited by Calliban (2020-01-15 17:37:46)

SpaceNut · 2020-01-15 18:05:04

The better than nothing from excess energy for all storage modes is just that but its not a very good supply for a rainy day.
If anything the poor and homeless could get a better efficiency than some of the proposed storage methods. The electric companies will never drop there prices so that people might use more of the excess or to be able to keep the lights on so lets keep looking for the technology that stores at a better efficiency.

tahanson43206 · 2020-01-15 18:43:09

For Calliban re #9

Thank you for your reply.

First, I do not doubt your 90% figure, but I have no idea where you are coming from. It is entirely possible we are trying to compare apples and oranges.

Second, I am hoping the university folks who published the YouTube video Louis found will agree to stop by to help us (and other forum readers) gain a better understanding of the process.

Please visit newmars.com/forums. There is a lack of understanding but much interest. tahanson43206

Calliban wrote:

tahanson43206 wrote:
For Calliban re #7
Tahanson, did you read any of the analysis I carried out? If you try and store energy in iron powder you lose over 90% of what you started with. In what universe could that possibly come out looking good? You have to pay for every single unit of electricity that is wasted in this way. None of it is free, because all of it depends upon investment in capital equipment.

Are you starting from ore? That might account for the 90% figure.

If you start from a carload of rust recovered from a plant where it had been reacted with oxygen, then the energy invested in removing the oxygen should be amenable to recovery by careful design of the process.

Here is a quotation which reports that the efficiency of charging a battery can be as high as 90%

From Google: search: what is the efficiency of charging a battery

Battery Efficiency
The higher the rate of charge or discharege, the lower the efficiency. The state of charge of the battery will also affect charge efficiency. With the battery at half charge or less, the charge efficiency may be over 90%, dropping to nearer 60% when the battery is above 80% charged.
https://www.solar-facts.com/www.solar-facts.com › batteries › battery-charging
Charging and Discharging Lead Acid Batteries - Solar-Facts

Your prediction of efficiency would appear to be 10% for iron powder recovered from rust.

You may well be right. There ought to be a way to confirm your prediction.

Thanks again for taking part in this discussion!

Edit: I thought the 90% charge efficiency figure was low, and suspect it was for pre-Lithium battery technology.

Here is a figure of 99% for Lithium ion battery technology:

https://batteryuniversity.com/learn/art … er_sources

Efficiency
The battery is highly efficient. Li-ion has 99 percent charge efficiency, and the discharge loss is small. In comparison, the energy efficiency of the fuel cell is 20 to 60 percent, and the ICE is 25 to 30 percent. At optimal air intake speed and temperature, the GE90-115 on the Boeing 777 jetliner achieves an efficiency of 37 percent. The charge efficiency of a battery is connected with the ability to accept charge. See BU-808b: What causes Li-ion to die? under Coulombic Efficiency.

Like flow batteries, iron powder "battery" systems should last far longer than competing technologies, but the crude energy removal process would consist of mechanical devices which would wear out.

At least flow batteries deliver electricity directly.

(th)

Last edited by tahanson43206 (2020-01-15 19:04:55)

louis · 2020-01-15 18:44:03

I've got a proposition for you: I make matchsticks...I can sell 100,000,000 and get a good income from that every year but every year I always seem to end up with a surplus of 100,000 matches that I can't sell. So those 100,000 matches are worthless as far as I am concerned. If you can find a way of offloading them I would gladly give you them for free as long as I get 10% of the profits from your enterprise.

Calliban wrote:

louis wrote:
You can discount the energy costs of making the iron powder and recycling it as waste electricity will be used (ie excess electricity produced by renewables above the level of demand, which would otherwise be earthed). The marginal cost of waste electricity is close to zero. Iron is being made all the time, for purposes other than providing a fuel, so in effect you can switch to the waste electricity as required...in effect I think you would be renting time at the furnace to make your iron. Could be dealt within on an annual basis...e.g. the agreement could be that you get 20% of the iron output per annum and you provide 20% of the energy required (via waste electricity) over the year while making a proportionate payment towards the capital and operating costs of the furnace.
I'm not sure what process is involved in recycling rust exactly - ie does it go back into a furnace? I guess it probably does.
Calliban wrote:
You use huge amounts of high grade electricity to make iron, with significant energy losses. You then burn it in a boiler to produce electricity, with most of the embodied energy being lost as waste heat. What's more, the reduction furnace will sit idle much of the time and the refractory lining will cool and develop stress fractures.
If you are going to make iron, I think it more likely that you would want it to be part of a continuous steady-flow process. It is also most valuable as an end product in itself for structural engineering purposes. It makes no sense burning it.
Louis I have a business proposition for you. I propose that you send me £10,000 of your excess income each year, in whatever random instalments you like. In return, I will pay you back £780 at whatever time in the year you like. It is excess income, that is over and above what you need to buy food and stay alive. So presumably, it has no value. What's not to like?

tahanson43206 · 2020-01-15 19:09:58

For Louis re #14 ...

By any chance can you see where Calliban is missing the point you are trying to make?

As an onlooker, it would seem the two of you are talking past each other.

I hope the folks who created the YouTube video you found will stop by to help out.

They appear to be reporting success with early installations, as reported in their web site.

(th)

SpaceNut · 2020-01-15 19:34:17

Excess manufacturing matchstick means the following year you make less not the same or more as you are using a predictor of sales to account for production.

SpaceNut · 2020-01-15 19:39:02

The "charge efficiency, and the discharge loss" are not counting the circuit loses to charge and the mismatch of circuit to use the energy from the battery, as they only accounted for the contact resistance and internal heating loses of charging.

louis · 2020-01-15 19:50:43

Marginal cost - that's where I'd say he was missing the point. Renewables create lots of waste electricity that at present has to be earthed (ie not used). If you can use that wasted energy to power an iron-fuel combustion process then that is a game-changer.

Basically the cost of iron fuel energy will be spread across the whole energy system.

tahanson43206 wrote:

For Louis re #14 ...
By any chance can you see where Calliban is missing the point you are trying to make?
As an onlooker, it would seem the two of you are talking past each other.
I hope the folks who created the YouTube video you found will stop by to help out.
They appear to be reporting success with early installations, as reported in their web site.
(th)

SpaceNut · 2020-01-15 20:33:28

Powdered iron does have storage issues in that it will be effected by moisture, salts and of course oxygen while awaiting combustion to energy state change. The longer the period the more change will occur for the iron powder and the less energy you will get out of it..

tahanson43206 · 2020-01-15 20:55:52

For Calliban ... I made time to go look at the Wikipedia article you cited.

For forum readers who have not yet followed the link, the article contains a table showing a number of substances, and provides energy content and other properties.

Iron shows up as having about 1/10 the energy content per Kg as many familiar energy storage chemicals.

Iron has the distinct advantage over ALL the Carbon based fuels of NOT sending Carbon into the atmosphere.

Unlike coal, which produces solid waste that cannot be re-used, the iron process yields an output that can be completely recycled.

One uncertainly I have about the process as reported in the original YouTube video Louis found, is absence of mention of participation of water in the combustion process.

I found a discussion of this point in stackexchange:

https://chemistry.stackexchange.com/que … hout-water

Note that water is not required if the temperature of the iron and oxygen are sufficiently high. I do not know the precise temperature, but from experience with welding I can say that noticeable amounts of orange-colored iron oxide begin to form as steel approaches its melting point, which is around 1370 degrees C (2500°F). This high-temperature oxidation in air, without water, is similar to what we usually call charring or burning. – Ralph Dratman Feb 21 '19 at 18:22
@RalphDratman That sounds accurate. Heat basically prompts iron to react with oxygen, first giving FeO, and with more oxygen in the fray, Fe2O3 (rust). We could say that's the actual way that rust is formed, and water acts as catalyst (makes the same reaction possible with lower energy (heat) requirement. – Jerry Feb 21 '19 at 18:35
add a comment

OK! That would explain how the YouTube video would work without water.

The combustion process needs to be primed to a temperature above which it can sustain itself with sufficient input of iron and air.

This means it would (most likely) lend itself to an industrial setting.

The Wikipedia article shows that Iron has a volume rating of 40.68 MJ/Liter.

Anthracite coal, for comparison, has an energy content of 26-33 MJ/Kg and a volume rating of 34-45 MJ/Liter

In my power plant example given earlier, the comparison would imply that a train to fuel the local power plant would require ten times as many cars, and they would go back to the source full of rust instead of empty.

Furthermore, MORE cars would be required for the return trip, because of the oxygen content ...

en.wikipedia.org › wiki › Rust
Rust - Wikipedia
Rust is an iron oxide, a usually red oxide formed by the redox reaction of iron and oxygen in the ..... As rust has a much higher volume than the originating mass of iron, its buildup can also cause failure by forcing apart adjacent parts — a ...

Pursuing the topic of rust a bit further, I found this:

https://techblog.ctgclean.com/2012/01/s … bout-rust/

This article is about the kind of rust that forms in the presence of water and oxygen. It is NOT what the folks who created the YouTube video Louis found are talking about.

This leads to a question I hope they will answer ... how do they keep water OUT of the reaction?

Perhaps the high temperature required insures that water vapor does not participate in the process, even if it is present.

(th)

tahanson43206 · 2020-01-15 21:15:07

For Louis re topic ...

Your interests appear to include economics and business operations, among many.

Calliban is (quite rightly) skeptical (or at least so his posts imply) of the practicality of iron as an energy carrier.

However, on an industrial scale, I think it has a lot going for it, and I'm hoping you will be able to help to flesh out a scenario ...

Consider a large (very large) coal fired electric power plant located in a Midwestern state.

This large power plant consumes coal which is carried from coal fields some distance away using railroad trains.

Now consider wind farms in Texas and Oklahoma and other western locations where wind is readily available but power lines are not available for nationwide distribution.

Can a business case be made:

1) Make pure iron powder from spent iron rust particles brought in by train
2) Deliver pure iron powder to the power plant
3) Consume the iron powder generating electricity via good old fashioned coal style steam equipment
4) Do NOT deliver carbon to the atmosphere and thus earn Carbon credits
5) Do NOT deliver solid waste to land fills and thus avoid disposal costs
6) Return the spent fuel to the wind farms.

Do you imagine this scenario could be made to work with the carbon credits?

Do you imagine the scenario could be made to work WITHOUT the carbon credits?

For sure stock holders of railroad companies will see increased use of the rail system.

Edit: An automated reply arrived from the SOLID folks:

Thanks For Getting in Touch
We have received your message in good order. We will get back to you as soon as possible!
Eindhoven University of Technology, Eindhoven, Netherlands
Check out our website

From the SOLID web site:
https://www.teamsolid.org/collaborators

The Metal Power Project aims to develop a 100kW metal fueled steam generator with its project partners. The realization of this demonstration system is an important step towards applying Metal Fuels technology in the energy sector.

Edit#2: Reminder .... at Mars, there is plenty of iron oxide available as a feed stock for the process.

An exception from the Earth situation is that oxygen needs to be saved during the "re-charging" process.

Mars is red now, but it may have looked like charcoal in the past. ... The simple explanation for the Red Planet's color is that its regolith, or surface material, contains lots of iron oxide — the same compound that gives blood and rust their hue.Aug 8, 2012
https://www.space.com/www.space.com › 16999-mars-red-planet
Why Is Mars Red? | Space

Edit#3: On why Mars is red ...

https://www.space.com/16999-mars-red-planet.html

Why Is Mars Red?
By Natalie Wolchover
Plain-old iron looks shiny black. The element only takes on a reddish tinge when it has been exposed to oxygen, and enough oxygen at that for it to become iron(III) oxide, an atomic fivesome composed of two iron atoms and three oxygen atoms. So why did so much of the iron on Mars' surface oxidize, or gang up with oxygen?

(th)

Last edited by tahanson43206 (2020-01-15 22:33:06)

Calliban · 2020-01-15 22:42:07

louis wrote:

Marginal cost - that's where I'd say he was missing the point. Renewables create lots of waste electricity that at present has to be earthed (ie not used). If you can use that wasted energy to power an iron-fuel combustion process then that is a game-changer.
Basically the cost of iron fuel energy will be spread across the whole energy system.

It is not a game changer if it is 10% efficient or less. It only works if the source energy is basically worthless. Even in the fantasy world of a completely wind-solar energy future, it is doubtful that it could compete against other methods of energy storage. Even hydrogen, which is a net energy sink itself, would have a huge cost advantage over this precisely because source electricity is not free. At 10% efficiency, you are pouring valuable energy that has to be paid for into waste.

I could launch into analysis, but it wouldn't sway either of you because you won't read it. Like Kbd said, people believe what they want to believe. Louis has been selling the same basic vision here for a decade or more. It doesn't matter how many times it gets shot to pieces by arithmetic carried out by any number of people, he believes because he wants to. His choice. But have you noticed how many serious and critical minds this board has lost? It is deeply tiresome debating with people that have already made up their minds and are not interested in inconvenient facts.

Terraformer · 2020-01-16 04:07:22

Re. compressed CO2, if kept below 233K it will liquify at 10 bars of pressure. Storing liquid CO2 will require a lot less space, and ambient heat (perhaps stored from the heat released when it's liquified) can be circulated in to keep the pressure up. I wouldn't want to live near such a plant, though - a large amount of cold CO2 is quite dangerous. Maybe an alternative gas could be used, that would escape into the atmosphere (ethane? Ammonia?).

louis · 2020-01-16 09:19:16

A bit of ad hominem is a sure sign an argument is on shaky ground.

You claim that free or, shall we say, "nearly free" electricity won't be available to power the iron process. I don't accept that. We know that in real world conditions lots of renewable energy is currently earthed because it is surplus to requirements. As you increase the percentage of solar and wind, the amount of waste electricity produced will inevitably increase.

The marginal cost of producing that waste energy is tiny and its current price is effectively zero because no one wants to buy it. If renewable energy companies could use that electricity to make the whole of the energy system non-intermittent that will be a huge economic gain to them. It will mean they can not only supply baseload but also respond quickly to increased demand. Not only is it more economic for the supplier, it is more economic for the grid operator who can now decommission some expensive plant as intermittency is being taken out of the system.

I don't think anyone yet understands the costs of an iron system relative to hydrogen or chemical batteries, but we do know that storing and handling hydrogen is challenging and expensive. Storing iron powder has got to be easier than that, and so I suspect storage costs will be much lower for iron.

Calliban wrote:

louis wrote:
Marginal cost - that's where I'd say he was missing the point. Renewables create lots of waste electricity that at present has to be earthed (ie not used). If you can use that wasted energy to power an iron-fuel combustion process then that is a game-changer.
Basically the cost of iron fuel energy will be spread across the whole energy system.
It is not a game changer if it is 10% efficient or less. It only works if the source energy is basically worthless. Even in the fantasy world of a completely wind-solar energy future, it is doubtful that it could compete against other methods of energy storage. Even hydrogen, which is a net energy sink itself, would have a huge cost advantage over this precisely because source electricity is not free. At 10% efficiency, you are pouring valuable energy that has to be paid for into waste.
I could launch into analysis, but it wouldn't sway either of you because you won't read it. Like Kbd said, people believe what they want to believe. Louis has been selling the same basic vision here for a decade or more. It doesn't matter how many times it gets shot to pieces by arithmetic carried out by any number of people, he believes because he wants to. His choice. But have you noticed how many serious and critical minds this board has lost? It is deeply tiresome debating with people that have already made up their minds and are not interested in inconvenient facts.

Last edited by louis (2020-01-16 14:49:33)

tahanson43206 · 2020-01-16 10:31:01

For Louis re #24

Hopefully your calm reply will help to put things back on track.

For Calliban ... this is just a judgement from watching for a while, but I ** think ** that Louis is a valuable part of the forum ecosystem precisely BECAUSE he is resistant to persuasion by logical argument. This pattern has resulted in amazing posts by knowledgeable folks such as yourself. All those posts remain available for review by new visitors to the forum for as many years as the Mars Society is willing to fund the servers.

Potentially, that could be a long time.

When you write, please write for the long term readers, who do not have your background and who will often be influenced one way or the other by your views. If you are overly pessimistic about a new technology, you might inadvertently steer folks away from learning about it, and discovering potential of which no one is aware.

I appreciate the fact you often include references in your posts, and I hope you will continue and perhaps even expand that practice a bit.

It seems to me that Louis often plays the role of a sparring partner for a professional boxer. The pro does not (usually) get mad at the sparring partner when he lands a punch.

If there is something about using iron as an energy carrier that you think violates the laws of physics, we need to know that right away.

If the discussion descends into opinion about sales prospects, when the potential of the technology is not yet known, all of us are on shaky ground.

In any case, thank YOU for your contributions in multiple topics.

And! Please keep your asteroid topic going! It is a topic you created, and one which I think has significant potential for development.

You can add to that topic for months without having to deal with feedback, and in doing so you'll be creating a series of nuggets of information which have the potential to be inspiring to future readers, some of whom may be able to build businesses folks of our generation can imagine but perhaps not realize.

(th)

Last edited by tahanson43206 (2020-01-16 10:35:04)

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Iron fuel energy storage (to support renewables)

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