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I'm coming round to the idea that early manufacture of PV cells on Mars will be easier than I imagined.
These videos are helpful in demystifying some of the processes involved in manufacture dye sensitised cells.
https://www.youtube.com/watch?v=KLIocQU8nQg
https://www.youtube.com/watch?v=8DQt8Sd1qgY
https://www.youtube.com/watch?v=vsUfIY37pII
Of course, we will need to provide the Mars settlers with the right machines to produce the cells, to replace a lot of the human labour with automated machine work.
The benign weather conditions on Mars mean that the housing for PV can be lightweight.
Dye sensitised cells are, I read, quite low efficiency (about 11%).
https://en.wikipedia.org/wiki/Dye-sensi … Efficiency
If we could realise 0.1 KweH per sol per sq. metre of PV on Mars, 1000 would produce 100 KweHs per sol - an average constant of perhaps 3 Kwes.
I don't see anything standing in the way of manufacturing PV panels. We can "mine" the titanium from the surface regolith.
Carbon can be obtained from CO2. Presumably the glass or polycarbon materials can be produced without great difficulty.
It would be great if a Mars Consortium focussed on the design of small scale machines that could produce such cells in an automated process. If 200 a sol could be produced, then at the end of a 650 sol mission, you'd have 130000, enough to give you nearly 400 Kwes constant.
I haven't look in detail at silicon cells yet...I appreciate DSSCs degrade quickly, but I read there are some ideas on how to slow down the degrading process, ie protect against UV.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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From what I remember back on the old Red Colony site some of the solar inks are simular to consistancy of what we would put in an ink jet cratridge and could be printed onto glass or plastics.
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Here's a nice summary of what is involved in producing a silicon-based PV cell.
http://www.madehow.com/Volume-1/Solar-Cell.html
I don't see anything there that could not be replicated on Mars, possibly with some small importation of specialist materials from Earth in the early stages.
An electric arc furnace for purification - v. doable.
As for doping, boron and phosphorous are present on Mars.
As for the anti-reflective coating, titanitum dioxide is well represented.
We can heat the panels in ovens, using already imported PV panels and chemical batteries, to boost power.
Aluminium is available for the frames.
Basically we need a small scale production line, with automated machines handling the purification, doping, coating, baking, and
The role of humans would be mostly confined to monitoring and maintaining the machines, locating and feeding in the required chemicals,
ensuring power supply, moving the wafers during the processing from one machine to another and transporting the finished products to their desired locations.
For a settlement of 100, I am thinking this might be a job for two people, producing maybe the equivalent of 200 sq. metres of panelling in 100 x 2 sq. m units every sol.
Eventually the Mars colony will be able to build the automated machines involved in the processing. Even before they build 100% of the machinery, they will be able to construct much of the mass, with some of the more complex parts being brought from Earth.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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Encapsulated organic cells have lifetimes of a few thousand hours on Earth, after which UV damage fatally degrades them.
On Mars, the UV damage rate to photosystems (i.e. chlorophyll) is about 1000 times higher than on Earth (See Table 1 in the link below).
http://www.atmos.washington.edu/~davidc … ng2000.pdf
How long will those organic cells last in an environment like that? How long would the polyethylene backing and encapsulation last? Even if these things are very cheap, they aren't much good if you have to replace them on a timescale of weeks.
Last edited by Antius (2017-06-02 04:24:52)
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I am not arguing for the DSSC approach but the UV degradation effect can be ameliorated it seems with only small reductions in efficiency :
https://www.hindawi.com/journals/ijp/2012/506132/
That said, silicon based PV seems a safer bet.
Again, I think it is doable on a smallish scale.
Encapsulated organic cells have lifetimes of a few thousand hours on Earth, after which UV damage fatally degrades them.
On Mars, the UV damage rate to photosystems (i.e. chlorophyll) is about 1000 times higher than on Earth (See Table 1 in the link below).
http://www.atmos.washington.edu/~davidc … ng2000.pdfHow long will those organic cells last in an environment like that? How long would the polyethylene backing and encapsulation last? Even if these things are very cheap, they aren't much good if you have to replace them on a timescale of weeks.
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According to Wiki, the embodied energy in thin-film solar is 1305MJ/m2.
https://en.wikipedia.org/wiki/Embodied_energy
Full sun at the top of the Martian atmosphere is 590W/m2. Assuming a 70% transmittance of solar energy through the Martian atmosphere (after dust scattering, IR and UV absorption) the RMS power reaching the Martian equator during daylight hours is 292W/m2, or 146W/m2 averaged over the whole day. For 10% efficient thin-film cells, average power output is 14.6W/m2.
To produce a baseload energy supply using synthetic propellant production to store energy, we must gather 3 units of energy for every 1 unit of baseload power. That is because energy storage in chemical fuels is no more than 25% efficient in the real world. So after buffering, the power output of 1m2 of solar panel is 4.87W. The total payback time for the solar cells alone is therefore 8.5 years. It is questionable whether thin-film cells would survive that long in the high-UV environment on Mars. And payback period doesn't account for the continuous decline in cell efficiency, the energy cost of power transmission or the embedded energy used in making the energy storage system. Include that and payback time will be above 10 years (remember the energy storage system is basically a whole other power plant).
Unless the energy investment required to build these thin film solar cells is substantially lower than traditional thin film technologies (I mean more than an order of magnitude lower) it would be difficult to get excited about the prospects for thin-film silicon PV on Mars. It is close to being an energy sink.
Last edited by Antius (2017-06-02 08:00:17)
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Thin film is only relevant to the first few Missions, where we are exporting PV panelling to Mars from Earth. Beyond say the first three Missions, 6 years in or thereabouts, I don't see why Mars can't build it's only energy infrastructure using a combination of solar reflector turbines and more durable PV panel manufacture, with PV panel manufacture eventually taking over. They can also build their own batteries.
14.6 W/m2 gives you 146 Kws for 10,000 sq. metres (i.e. 100x 100 metres). As explained elsewhere, with a solar energy system, most energy expenditure will be during the energy when energy is available, not at night when it isn't.
According to Wiki, the embodied energy in thin-film solar is 1305MJ/m2.
https://en.wikipedia.org/wiki/Embodied_energy
Full sun at the top of the Martian atmosphere is 590W/m2. Assuming a 70% transmittance of solar energy through the Martian atmosphere (after dust scattering, IR and UV absorption) the RMS power reaching the Martian equator during daylight hours is 292W/m2, or 146W/m2 averaged over the whole day. For 10% efficient thin-film cells, average power output is 14.6W/m2.
To produce a baseload energy supply using synthetic propellant production to store energy, we must gather 3 units of energy for every 1 unit of baseload power. That is because energy storage in chemical fuels is no more than 25% efficient in the real world. So after buffering, the power output of 1m2 of solar panel is 4.87W. The total payback time for the solar cells alone is therefore 8.5 years. It is questionable whether thin-film cells would survive that long in the high-UV environment on Mars. And payback period doesn't account for the continuous decline in cell efficiency, the energy cost of power transmission or the embedded energy used in making the energy storage system. Include that and payback time will be above 10 years (remember the energy storage system is basically a whole other power plant).
Unless the energy investment required to build these thin film solar cells is substantially lower than traditional thin film technologies (I mean more than an order of magnitude lower) it would be difficult to get excited about the prospects for thin-film silicon PV on Mars. It is close to being an energy sink.
Let's Go to Mars...Google on: Fast Track to Mars blogspot.com
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So basically, Martian industrial infrastructure has to be shutdown for 75% of the time, as it has to align with an intermittent power supply. By doing that, you are shifting costs elsewhere - lowering storage costs by increasing marginal capital costs in whatever is using the power. Most industry wouldn't stay in business very long if it did that on Earth. On Mars where most infrastructure is imported at enormous cost, it is rather absurd.
We have already examined solar dynamic power on Mars. EROI was ~4, which implies an energy payback time of several years on Mars. That makes for expensive power and low growth rate, as you must wait several years just to recover the energy needed to build the plant in the first place.
Polycrystalline silicon cells have an even higher embodied energy than thin film - about three times greater, but they are 15-20% efficient, so will yield 1.5 - 2 times as much electricity. Even if no energy storage is used, energy payback time is still 4.4 years and EROI would be <5 for a 20 year cell life. If methane/oxygen storage is used, payback time is 13.2 years, which isn't workable at all. Again, the technology suffers from poor energy economics.
Last edited by Antius (2017-06-02 10:14:32)
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Labour is labour. You can't work people 100% of a sol. If they work 50% of the time, then essentially it doesn't much matter when they work (although some night time monitoring duties will probably have to be shared). Industry, especially activities like smelting, is energy-intensive so we should expect big shifts in energy usage.
I've put the question to you on the other thread whether you are going to have any energy storage with the nuclear proposal. If not, you are limiting all activities to 100 Kwe at any one time in a 100 Kwe system.
Your last para shows the limits of EROI analysis.
If I start with a PV powered system, as long as I can build more PV panels and more manufacturing units before I reach the end of the arbitrary energy accounting period you have chosen then I am "in business". Your approach is a bit like saying Amazon is not a viable business because it's never posted a dividend to shareholders (true I believe) - whereas the truth is it is viable because it ploughs surplus back into expanding the business.
What we would need to focus on is not your EROI but how much labour time would need to be committed to building PV panels and other aspects of the industrial infrastructure. This is of course is where the productivity element comes in - something else you disregard. Labour on Mars will be super-productive since it will have some of the most productive automated machinery at its disposable from 3D printers, to CNC lathes, to steel making, to metals processing etc etc. As long as the labour time commitment is reasonable then an expanding solar economy is possible. I think probably something like a maximum of 15% of the labour force working on PV panel manufacture (and other related energy infrastructure projects) would be reasonable.
So basically, Martian industrial infrastructure has to be shutdown for 75% of the time, as it has to align with an intermittent power supply. By doing that, you are shifting costs elsewhere - lowering storage costs by increasing marginal capital costs in whatever is using the power. Most industry wouldn't stay in business very long if it did that on Earth. On Mars where most infrastructure is imported at enormous cost, it is rather absurd.
We have already examined solar dynamic power on Mars. EROI was ~4, which implies an energy payback time of several years on Mars. That makes for expensive power and low growth rate, as you must wait several years just to recover the energy needed to build the plant in the first place.
Polycrystalline silicon cells have an even higher embodied energy than thin film - about three times greater, but they are 15-20% efficient, so will yield 1.5 - 2 times as much electricity. Even if no energy storage is used, energy payback time is still 4.4 years and EROI would be <5 for a 20 year cell life. If methane/oxygen storage is used, payback time is 13.2 years, which isn't workable at all. Again, the technology suffers from poor energy economics.
Last edited by louis (2017-06-02 18:15:23)
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I know that we talked about dye solar cell in a more recent topic but this is the one which came up with search of the forum...
Breathing new life into dye-sensitized solar cells
10.7%, the highest yet for this kind of dye-sensitized solar cell, the most efficient solar technology available at present.
Current dye-sensitized solar cells are made up of a porous layer of titanium dioxide covered with a molecular dye.
As sunlight is taken in, electrons are excited as they pass through, and are collected for power, before being 'recycled', reintroduced into the electrolyte and back to the dye molecule. As they are lightweight and low density, they have a high industry appeal as a replacement material for current rooftop solar panels.
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SpaceNut,
Any sort of Mars-made PV needs to be a highly-automated reel-to-reel process that uses inks / dyes / chemicals that are sprayed / printed onto some kind of plastic or Carbon-based substrate. The lighter and more conductive or more non-conductive, dependent upon specific electric component application, the better.
Similar to structural applications, CNT's would really shine here as well. There exists the possibility of "baking in" the voltage and amperage regulation electronics through weaving of fibers with different resistance values or through application of chemical coatings. The CNT's are also incredibly resistant to catastrophic failure from flexure with wild temperature swings. NASA actually gave up on trying to break or weaken CNT's after 5 or 10 million cycles or so, thus their ultimate life-cycle limitations prior to failure remains unknown. Suffice to say that it's far in excess of any known plastic or metal. Anyway, these sorts of electrical-interconnects would make electronics failure from environmental factors functionally impossible in the Martian surface environment, thus ensuring that any panel so-constructed is, more or less, guaranteed to produce a given amount of voltage and amperage for life.
If we were also able to make super capacitors from such materials, despite the fact that the energy density / specific energy might be lower than the latest and greatest Lithium-ion battery, ISRU electrical power storage technology, largely sourced from the Carbon in the CO2 atmosphere, would also be of great interest to a fledging colony.
Graphene Supercapacitors 2.8V 30000F and 3V 12000F made in China
Louis should note that the energy density of these new super cap technologies are in the range of Lead-acid batteries, just like all practical flow batteries, but without the need for construction of giant steel tank structures for chemical storage / management, meaning more suitable for stationary power storage than flow batteries.
For anything that has to move somewhere, energy density is unlikely to ever compete with Lithium-ion batteries and fuel cells. However, there are no toxic chemicals and metals involved in the manufacturing process, electrical efficiency is about as good as Lithium-ion, and the base material used is Carbon, which Mars / Venus / Earth have functionally unlimited supplies of. There are also plenty of other places in our solar system where we can obtain more Carbon. We're highly unlikely to run out of Carbon in the foreseeable future, thus mining and refining of mass quantities of metals is not required.
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For kbd512 re #11 ...
Thank you for providing (what I think is) a nice capsule summary of a useful business for Mars.
***
For a reader who is not yet a member ... I am recruiting participants for the virtual city, Sagon City (2018) here on NewMars forum.
The idea is for 2750 individuals (or small teams) to take "ownership" of one of the 1 kilometer square plots, and to define a business that would make sense on Mars, and to define the characteristics of the plot, which would (could) support a family or perhaps a small community of workers.
The space under the surface would be available for uses in support of the plot, but the community plan calls for tunnels under the plots to provide for transportation and for utility services.
As you will see by reviewing the archived messages in the forum, there is a wealth of advice available on how to build a living and working environment on and in your plot.
In this case, I am hoping you will decide to provide PV products for other residents, and in the course of your research on how to do that, you will (or could) become an expert on the topic. Just coincidentally, that expertise would be immediately useful here on Earth.
(th)
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The factory plants to build insitu material solar cells must come from somewhere and its just not going to happen without some of that mass being offset by not as efficent material designs, machines and such as we will be starting with nothing.
We may just need to send the most required which we can not make even in a crud form on mars as the first means to remove that mass from the shipment to mars.
That is the trouble with mars and setting up plots also since we are not capable of sending much at this time to mars....
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For decades, slabs of crystalline silicon have dominated the solar industry. Other materials that can be layered in thin films, such as copper indium gallium selenide (CIGS) and cadmium telluride (CdTe), have captured less than 5% of the market, because it’s hard to make them as efficient or cheap as conventional solar panels. Perovskites could be a different story. They should be cheaper to make and seem impressively efficient at converting sunlight into electricity — in the laboratory, at least.
The methods and materials used on mars will be quite important....
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Organic solar cells do not last
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Bumping for technology developement
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