Talk:Cost of energy on Mars

Rick: Hi Michel.

There are something like 8 fourth generation reactors which are in the design or testing phase. If we assume that the Mars colony is happening in 15 years, it is very likely that we will have better reactors than the ones designed 75 years ago. China is building a commercial, 60 MWatt thorium, molten salt reactor which is scheduled to come on line in 2029. (It is an industrial reactor and a test bed. If it works well, they intend to build a lot more, but are debating the small modular reactor design, or scaling up to larger facility built reactors that produce a lot more power.)

The high cost of nuclear reactors is for two reasons: first the regulations are absurdly strict for the safest form of power (number of deaths per giga-watt generated), plus having to deal with protesters who have been taught to fear nuclear power. Second, they are giant, bespoke facilities built on site. If some company starts mass producing small modular reactors, the cost of nuclear will drop thru the floor.

Pressurized, light water reactors have to be giant, because they need a containment dome that can withstand highly pressurized water flashing to steam, and expanding in volume 1,000 fold. Many new reactors avoid high pressure water. E.g. molten salt reactors, pebble bed reactors, travelling wave reactors.

Further, every study that I've seen talking about the sky high cost of nuclear looks at building reactors in the west. They ignore the cost to build reactors in China, because China builds reactors for 1/8 the cost compared to the USA. Why? Maybe they are racist against Chinese people? Or more likely, looking at the cost of these Chinese reactors weakens their argument.

Re: Demand is reduced to 10%. Oh, Ok. Hopefully the colonists have grown and stored enough food, for the dust storm 'winter'. Given they do this (not being stupid), turning off industry and fuel building for potentially months is not optimal.

Re: Cleaning dust off. This is not a big problem on Earth because we don't have that much dust. As for automatically cleaning them, maybe we will have a mobile robot that can do that. But, that adds to the cost and mass of solar. If every solar cell has to have a washer / squeegee attachment, the mass & cost for each panel will be a lot higher.

I looked it up... a loss of 0.2% of power per Sol is typical, although observed rates of decrease in 'dust factor' vary between 0.05% and 2% per Sol. This is better than I thought, I was assuming that 0.5 to 1.0% per day was the typical rate (if I remember right, Opportunity was losing 1% per Sol, for a while there). So rather than having to clean panels more than once a month, it is closer to one cleaning every couple months. ^[1]

Give me a couple days, and I'll adjust what I wrote based on this discussion.

Did you notice that we are now manufacturing super critical Brayton Cycle CO2 turbines? 1/10 the mass of a steam turbine, and 10% more power!!! Ideal for Mars.

Warm regards, Rick.

Nice to wee all the work being done o the site!

I have to disagree with this, of course :-) DISCUSSION: The author above suggests that future advances will make solar cheaper, so shall we assume that the Mars colony will solely pay the cost of such improvements? If we assume we are using off the shelf solar technology, then we should assume we are using off the shelf nuclear tech as well. Detailed calculations on the costs and tradeoffs of future systems, when we have no idea of the transportation costs, and have no idea of what local industry can produce, seem futile. However, I suggest that this page remains, as the structure of the argument may be of use to people. Rick

If you look at most modern sources, Solar is already significantly cheaper than nuclear on Earth. There are real contracts for solar at 1-2 cents per kWh. There is no need for specific advanced technology, the technology is growing fine without Martian demand. Earth will pay for cheap solar, the demand is all here, and not on Mars. The Martian Market will always be tiny. There is no off the shelf nuclear technology for Mars. The solar energy sources proposed are not significantly advanced, but are minor adaptations, no?

We have actual suggestions of the transportations costs, albeit by a highly excentric individual, but who does own a rocket company.

Regarding storms, I propose that DEMAND be reduced to 10%, not that supply only goes down by 10%. It's silly to run food and fuel production during solar storms. We don't grow food in Canada during the winter, and we survived just fine. And we already survided before modern transportation by storing foods.

Cleaning the dust off: Is this a large cost on Earth? And isn't this just the task for a robot system? There will be robots in support, I expect, or is it cheating for solar to include them in the solutions? There have been many electrostatic systems proposed, and perhaps mechanical shakers might be enough?

Good catch about the more practical 2 MW reactor, will use that instead of Kilopower, and likely nuclear will rule the day. Perhaps the discussion about thorium should go into the Thorium page?

In general it would be simpler to remove all mentions of nuclear fuel limitations from this page, as it's rather speculative, one way or another?

Thorium reactors are cheaper, or more economical. They are not more efficient in the usual sense of efficiency. Kilopower is only 25% efficient and future Martian reactors might not be optimized for fuel efficiency but for cooling system costs.

There is no way a reactor with moving parts will last 50 years. It's entirely speculative. 10 years is speculative too, of course, so likely a range or a table would be better. In that case, of course solar can go into a table as well.

Igneous rocks may not be precise enough. granites vs basalts might be a better division, and basalts, I believe, are poor in thorium. Again best discussed on the Thorium page.

If solar is not the primary power source, it becomes more attractive. A Martian colony is likely to be power starved. Some industrial processes could be scheduled for periods of peak sun. For example, a solar furnace could be loaded at night, and in the day time fire ceramics. Solar heat could be moved into masses with high thermal inertia, which would keep the colony warm at night. Growing plants require gigantic amounts of light, and with an approximately 24 hour day (??), solar is suitable for crops. A fair (??) bit of water is frozen in the subsurface soil of Mars, and solar power could heat patches of ground to release water vapour to be captured and condensed.

Erased this as it has nothing to do with the cost of solar, but rather with technologies and only confuses the issue. Direct solar can be used with any other technology, be it photovoltaic or Nuclear. Waste thermal energy will also come from either a nuclear reactor or cooling of production areas.

If we are going to compare solar and nuclear, a fair comparison should include the cost of developing a specific nuclear reactor for Mars.

The assertion that Mars is extremely low in radioactive should be discussed. Radioactive ores on Earth are usually found in igneous rocks, and Mars has had a similar history of vulcanism, indeed, Mars has more igneous rocks exposed on the surface than Earth. Thorium and radioactive potassium has been found by the Odyssey orbiter, but it does not detect ore bodies, but dust and surface soils to a maximum of 1 meter deep. (If Odyssey was orbiting Earth, it would not find thorium ores, but rather detect the low levels of Thorium found in soil everywhere.) So I do not consider the low levels of potassium/thorium found by Odyssey to be strong evidence that Mars lacks radioactive ores.

- This is wrong. the average thorium on Earth in dirt is known and is about 6ppm. If the average dirt on Mars is 1 ppm, then the availability will be lower. Six times less is not slightly less.

Sorry to say this but sources (5) and (7) are wrong, they seem to be convincing fabrications. The same author, in longer papers, goes on to discourse about the Face on Mars, Martian nuclear wars and other follies. Actually, just read reference 7 to the end, wonder at how that author ever got published, and erase the reference.

// Rick here. Make a page which organizes the arguments for amount of U/Th/K on Mars? Spend more time on this later.

Michel: The Thorium page presents the arguments about surface concentrations. It would be good to add the arguments about abundance and core separation mechanisms. If much of the northern hemisphere is a former sea, then the Thorium might be at the bottom of it :-) However then the southern hemisphere should have more and that is not visible in the satellite data. It only takes one mine to make Thorium or Uranium work as an energy source, of course. We can compare with thorium on the Moon, mapped using similar instruments, where a known geological mechanism called Kreep created concentration of up to 10 ppm in large areas, but where the basalts are between 0 and 2 ppm.

Granites on Earth, on the other hand, have a normal concentration of 22 ppm, and there are large formations at over 50 ppm.

There are likely to be granites on Mars: https://arstechnica.com/science/2015/07/curiosity-finds-continent-building-rocks-on-mars/ So these might be possible sources for Thorium concentrations. Time to send geologists!!

Meteoritic impacts might also have helped to concentrate minerals, hence metals, in hydrothermal vents, or in magmatic chambers. However, the minerals need to have been there in the first place.

I have moved most of the discussion of the rarity of radioactives into its own page. Welcome comments there.

Warm regards, Rick.

I've redone the calculation with the much improved reactor. As expected, nuclear now wins the race. The developments costs are a hopelessly speculative subject, but likely the army/ US gov in some manner will foot the bill to develop small nuclear reactors, so I've excluded them. I have a spreadsheet if you are interested.

Nice job on the revision Michel. However, I don't see cost and mass estimates for a) equipment to track the sun across the sky, b) the batteries + methane generators to keep them up for weeks or months long dust storms, and c) automated equipment to dust the panels.

Moving parts are liable to be problematic on Mars because of the dust.

Super accurate numbers are not needed. Even very favourable, super-optimistic values are ok. But I think that SOME value would be better than none, so that they can be considered and updated if better information comes along.

Warm regards, Rick.

The mass target is 3.5 kg/m2 to take the rotation elements, batteries and backup power systems into account. The NASA Mass target is actually 3 kg/m3, so I'm pretty confident. I'm not too worried about the dust. The rovers have been doing OK despite it all. And the motion is very limited and repetitive so should be easy to have booties around the moving parts. Yes, the point of the article is to have a target, not to be precise. I think my conclusion is more or less in the ballpark, but yes, will evolve with time, as it has just done :-)

Best, Michel