Power generation on Mars

Adrian · 2001-10-19 06:21:17

My interest in this subject was piqued when I read an article about the use of windmills on Mars to produce energy. Traditionally, most people think that either solar power or nuclear power is the way forward, at least for initial colonies and manned exploration missions (geothermal and so on would require a more extensive engineering and surveying effort).

However, there is of course a certain stigma attached to nuclear power and unfortunately should you ever find yourself in a dust storm, solar power isn't going to do you much good. The NASA scientists are advocating the use of a dual power generation system in which solar power is used when there are clear skies and wind power during dust storms.

Why not use wind power all the time? Because on Mars, you need 30 metres per second windspeed to produce electricity and you only get that during dust storms. This strikes me as an elegant solution.

Personally, I believe that nuclear power is probably the most efficient system and in any case, nuclear power is pretty safe. What do other people think?

Phobos · 2002-01-06 00:35:57

One of the problems with producing power via nuclear generators is the radioactive waste that they produce. Disposal of it might pose a problem for Martian colonists, especially if the power is generated by fission (fusion should produce a lot less if any waste but isn't viable yet.) Also you'll probably run into a lot of political problems if you try to ship uranium from Earth to Mars. The anti-nuclear crowd has proven in the past that its not afraid to stand up to NASA on that issue. Then again I guess you could mine the uranium from Mars, but for a beginning colony I'm not sure if that would be practical. I like the windmill idea and solar power ideas, their clean and easily renewable energy sources. There might even be a geothermal vent or two that could be tapped though that might be wishful thinking.

Jim Oliver · 2002-01-09 19:44:03

If we are only considering privately funded missions to mars, I think solar or wind would be the only choices. Who is going to sell a couple pounds of fissionable material to us? The U.S. goverment would never allow it. And if they did, how would we keep it safe while we were still on earth? Someone is likely to try to steal it from us, killing lots of good people in the process.

So if we go with solar or wind, we just have to accept the fact that we are going to have HUGE panels, and at times we will have serious power restrictions. I don't see this as a deal-breaker. We just have to make them as thin and as practical as possible, and then plan the mission around them.

All things equal (which of course they are not), I would prefer solar because of the lack of moving parts, although they DO require sombody to sweep them off occasionally. And during dust storms the light at the surface is reduced but it is not zero (I saw the figure on the old message board but I can't find it anywhere.)

RobS · 2002-01-16 00:01:47

I am new to this forum, so I hope I am not missing some context. If nuclear power is not available for a surface Mars station, probably the best way to go is a combination of wind and solar, because dust storms that obscure the sun and decrease the efficency of solar arrays also can generate wind power.

I was searching about wind power on the web a few months ago and came across the specifications for the BWC XL-50 wind turbine. Its blades are 46 feet in diameter and it produces 50 kilowatts of power in a 25 mile per hour wind. The wind turbine sells for about $70,000 and installation adds another $15,000 or so. The start-up speed of the turbine is a 4.5 mile per hour wind.

I did some calculations (don't ask me how; it was a few months ago now) and figured that if the length of the blades were doubled to 92 feet, the windmill would make 1.5 kilowatts in a 25 mile per hour wind on Mars. If you increase the blade length another fifty percent to 138 feet (diameter, not radius) then in a 25 mph wind the turbine can generate 3.5 kilowatts on Mars. The start-up speed would probably be about 11 mph, but the wind turbine only makes 0.3 kw at that speed.

I don't know what the weight of such a wind turbine would be, but the blades would probably be fiberglass or could be made out of very light-weight substances, so it would probably be only a few tons. While the first wind turbines would have to be brought from earth, once there is any manufacturing capability at all, they would probably be pretty easy to make, as they are mechanically simple devices.

-- Rob Stockman

Bill White · 2002-02-05 10:58:05

The following would seem a real possibility for Mars power generation. It was found at www.aist.go.jp/NIMC/publication/annual99/08/08_14.html:

= = = = = =

UV Photoinduced Reduction of Water to Hydrogen in Na2S, Na2SO3, and Na2S2O4 Aqueous Solutions

K. Hara, K. Sayama, and H. Arakawa
[Journal of Photochemistry and Photobiology A: Chemistry, Vol. 128, pp. 27-31, 1999]

"Hydrogen was produced by ultraviolet (UV) light irradiation (>200 nm) in an Na2S aqueous solution without photocatalysts. Water (protons) appears to be directly reduced to hydrogen by excited electrons produced in photon absorption with sulfide ions (S2-). The maximum quantum efficiency for hydrogen formation, 8.9%, was obtained in a 25 mmol dm-3 Na2S solution. Marked amounts of hydrogen were produced under UV light irradiation in the aqueous solution of SO32- and S2O42- ions. S2- ion absorption began at 290 nm, SO32- at 275 nm, and S2O42- at 400 nm. Hydrogen hardly formed at all, however, in SO42-, I-, and SCN- solutions. "

= = = = = = = =

If I read this right, it seems a settlement could construct a large glass jar filled with water and Na2S - - set it out in the sunlight - - and allow the Martian UV to reduce the H2O to H2. Then siphon off the gases for combustion or use in fuel cells and re-fill with water to the proper concentrations for further operation.

In essence, this would be an inexpensive, easily constructed solar cell possibly able to be built on Mars using only local materials.

Disland · 2002-03-16 04:18:08

I think nuclear power would best be avoided, so I have been looking into other forms of wind turbine that may be of more use on Mars. The Savonius Rotor design looks to be one of the best bets. It would be much much lighter and easier to transport to Mars and is a high torque/ low speed machine so could be good for power generation even at non duststorm times.
It could be made of a fabric to make it even lighter and it turns whichever way the wind is coming, (reducing the amount of moving parts). The only problems are the low efficiency and could fail if the winds gust too high. The fact that the gearing is all on the floor make it easy to maintain and generally the size need not be huge to produce a decent amount of power.Wine Turbines

Another idea for electricity generation is human power. The Astronauts will be exercising not stop for the months they are in space; to stop the bone depletion etc; so why not rig the execise bikes with generators. OK you are not going to make megawatts, but why waste the energy as heat when you can top up the batteries when you want (on a calm night) in the comfort of the hub.
In emergencies, once the dust has warn down the panels and screwed with the turbine's gearing, it would be the only way to contact Earth.
On Yer Bike!
Pedal Power

Austin Stanley · 2002-03-18 20:51:30

A Nuclear Reactor is realy the only way to go. No other option can generate as much power for so little mass. It can do it 24 hours a day, regardless of weather. It also produces large amounts of waste heat which might be utilisable. It is also highly reliable, although the other alternitives certianly are not defficent in this area.

Solar Power is good for a back-up system, but would be much heavier than the comparible nuclear system. A solar pannel system would have good reliablity as well.

Fuel Cells (or other combustibles), are even worse than solar-power in terms of mass. However they are an excelent way to save power generate by other means (Solar or Nuclear), in case of a power-failure.

Wind Power, again are even worse than solar power in-terms of weight, and are not as reliable.

Geo-thermal power cannot be expected to be extracted on the first few missions. And so is not even an option.

---------

In terms of a existing colony, things change. While nuclear is still VERY attractive (especialy breeding reactors which could produce even more fuel), Solar-mechanical systems and Geo-thermal start to catch up. Where geo-thermal power is avliable it is clearly the choice, if only for the water. Solar-mechanical power performs slightly worse than nuclear power, but is lower-tech and so easier to engineer nativly, rather than having to bring it from earth. Solar pannels and wind power are simply to heavy for there power, and not reliable enough to be adquet.

Shaun Barrett · 2002-03-21 06:46:16

I'm a little confused about Bill White's hydrogen generator. Hydrogen is a wonderful
fuel on its own in Earth's atmosphere, and a marvellous fuel in space when used in
conjunction with an oxidiser such as liquid oxygen.
However, in a tenuous atmosphere of almost pure CO2 (i.e on Mars), hydrogen is
effectively an inert gas. What will we use for an oxidiser?
And Disland's idea of relying on pedal power sends shivers up my spine! By the time
we're reduced to exercise bikes in order to contact Earth, I suspect the contact will
only be to finalise funeral arrangements!
No, at least in the early stages, Austin Stanley (and Dr. Zubrin et al. ) are clearly
correct in advocating a fission reactor for electrical power. In fact, it may be some time
before a more practical solution can be found. And what's wrong with nuclear power
anyhow? It's not some satanic abomination! As long as adequate provision is made for
the disposal of spent fuel, it is easily the safest and most reliable power-source. Let's
keep cool heads about this!

AndyM · 2002-03-21 09:28:02

Well said, Shaun. Nuclear power is the only way forward, at least initially. Its time that we acknowledge that nuclear power can be useful in some situations and that its not something evil and dangerous. Alternative energy sources are great on Earth, but for a Mars mission, they are impractical and risky.

Take wind turbines for example. How would you erect a wind turbine with a rotor diameter of 42 meters on Mars (about 138 feet). The tower would have to be between 30 - 40 meters tall and an equivalent tower on earth weighs 25 tons. The three blades each weigh more than a ton, and the nacelle weighs about 20 tons. It will take considerable effort to lift 20 tons to a height of 30 meters, even in the low Martian gravity.

In addtion, there are several operational constraints. Wind turbines are actually very inefficient in gusty weather. They need steady wind conditions to produce quality power. Gusty weather also shortens their lifetime considerably and necessitates frequent maintenance. Also (and don't laugh) erosion of the composite wings in a dust storm could be severe. Some turbine manufacturers have problems with erosion of the wings due to rain on Earth. The erosion occurs on the leading edge of the wings and is caused by the high tip speeds , which can be around 70 m/s. It might seem strange but its true.

Bill White · 2002-03-21 14:13:58

For the record,

I am also a staunch supporter of using nuclear power for Martian settlements. The US Navy (and the Royal Navy for that matter) have a great many safe, efficient reactors used routinely on naval vessels. The technology is established and proven.

Indeed, a non-nuclear mission borders on being entirely infeasible, in my opinion.

Even with nukes, however, a permanent settlement will quickly use ALL of the electric power generation capacity coming from the reactors (plural, IMHO) especially if they use artificial light to supplement greenhouse growth.

Using sunlight and catalysts to break water into H2 and O2 - and burning the H2 with the O2 to generate heat and power with water as the combustion product- is a supplement to the nuclear reactors. Also, nuclear fuel is not limitless and supplemental power sources will postpone the inevitable re-coring of the reactor fuel rods.

Breeder reactors may be inevitable but open up a whole new can of worms.

Also hydrogen has significant advantages for use in rovers and other vehicles. Cannisters of hydrogen and oxygen can be used to run internal combustion engines without needing to use reactor electric power to charge fuel cells or batteries. Obviously the exhaust products (water) are recovered for recycling back into hydrogen.

If automated sunlight driven catalytic refueling stations were deployed at key points along rover routes, a hydrogen fueled rover could discharge its water into the facility, take on hydrogen and oxygen gas, and continue on its way hundreds (or thousands) of kilometers fom the nearest nuclear reactor. The discharged water would be catalyzed back to H2 and O2 for the next rover to arrive and refuel, or for the return trip of the original rover.

The bottom line is that the energy output of nuclear reactors is not limitless. The smaller reactors, like those on submarines and aircraft carriers will not support that large of an energy budget. I believe the giant US carriers each have FOUR (4) independent nuclear reactors. Run at full capacity, they do exhaust their fuel in a matter of years and when the nuclear fuel is exhausted, it takes considerable time and effort to refurbish and refuel the reactors, even using massive naval shipyards to do the work.

RobHazlewood · 2002-03-24 02:31:06

Is it possible to make solar panels on mars?

It you could make them, surely they would be the best option as it wouldn't require being sent from earth.

Doesn't the silicon in solar panels require being treated in a nuclear reactor? if so, that means that we would need need a reactor anyway. But it would only need to be small. Perhaps the reactor could be recycled from electricity generation when the outpost gets established properly.

Perhaps have a manned station on the moon creating solar arrays? I can't imagine it being too expensive. A 2nd gen RLV could get a crew into space, then they could transfer to another craft for transit to the moon. I can't imagine it being too expensive to maintain either once they are established. (crews rotation every 12 months or so)

I don't know about my non-original moon suggestion, but I think we should just look at what is available on mars for electrical generation.

-Rob

Lil_vader · 2002-03-24 19:22:22

I don't think silicon needs to be treated in a reactor. I've got a book that tells how to make a solar panel at home, and it really isn't that hard. The only question would be whether or not the chemicals are available on Mars, and if they can be purified easily.

RobHazlewood · 2002-03-24 22:36:29

Sorry, I think I got that mixed up with IC's (computer chips)

I'm pretty sure they need to be treated in a reactor.

-Rob

Austin Stanley · 2002-03-25 20:03:09

Well the refinment of Silicon for the production of solar pannels (as well as the refinment of the dupping materials) would undoubtably take oddles of energy, especialy heat energy. So a nuclear reactor would probably be necessary just to get the party started anyways.

------

As an aside, even if a disaterious nuclear accident (Meltdown)was to happen on Mars, the end result probably wouldn't be that bad. There's little risk of people in Space suits growing dome-grown food breathing or eating radioactive materials, and the additional radiation would proably be nothing in comparission to the normal background radiation on Mars anyways. The biggest threat to any growing settlement would probably be loss of power.

Bill White · 2002-03-26 13:29:08

Has anyone who is opposed to using nuclear reactors for powering a settlement ever attempted an energy budget, even on the back of an envelope?

I foresee the energy needs of any permanent settlement easily using up everything that a handful of "Rickovers" can produce.

Manufacturing silicon panels on Mars may need to wait awhile which is why I like the idea of using sunlight in other ways - such as cracking water into H2 and O2.

RobHazlewood · 2002-03-26 22:04:24

I know my moon non-idea is very ambitious. It would probably be reasonable only if silicon is not readily available on mars. Even then it would require a large population to support it.

I think the way in which electrical generation is going to be cheapest is by means of utilising what is available on mars. NOT what is cheap to bring from earth.

I think we pretty much all aggree that initially a nuclear reactor will be needed. In other threads i've stated that i'm concerned about nuclear fission for power generation. But that only applies to earth. Initially fission is probably the only sensible option.
My hope is that H-H fusion will become available. D-T fusion may be inconveniant due to not being able to get the hydrogen isotope easily on mars.

H-H Fusion really is the answer, however for obvious reasons we must look at other approaches, and the cheapest approach will probably involve utilising what is easily available there.

That limits us to:
-sunlight to split water into H2 and O2, then using fuel cell
-possibly solar
-wind (doesn't seem to attractive to me though)
-nuclear fusion (doesn't seem too likely in short term)
-nuclear fission (requires materials being sent from earth.. may be expensive)

What have I missed here?

I wouldn't be concerned about dust storms and no power at night (in case of solar); fuel cells are excellent batteries.

Any other ideas?

Would I be correct in saying that geo-thermal energy is not available, or extremly limited on mars?

-Rob

RobHazlewood · 2002-03-26 22:05:19

I know my moon non-idea is very ambitious. It would probably be reasonable only if silicon is not readily available on mars. Even then it would require a large population to support it.

I think the way in which electrical generation is going to be cheapest is by means of utilising what is available on mars. NOT what is cheap to bring from earth.

I think we pretty much all aggree that initially a nuclear reactor will be needed. In other threads i've stated that i'm concerned about nuclear fission for power generation. But that only applies to earth. Initially fission is probably the only sensible option.
My hope is that H-H fusion will become available. D-T fusion may be inconveniant due to not being able to get the hydrogen isotope easily on mars.

H-H Fusion really is the answer, however for obvious reasons we must look at other approaches, and the cheapest approach will probably involve utilising what is easily available there.

That limits us to:
-sunlight to split water into H2 and O2, then using fuel cell
-possibly solar
-wind (doesn't seem to attractive to me though)
-nuclear fusion (doesn't seem too likely in short term)
-nuclear fission (requires materials being sent from earth.. may be expensive)

What have I missed here?

I wouldn't be concerned about dust storms and no power at night (in case of solar); fuel cells are excellent batteries.

Any other ideas?

Would I be correct in saying that geo-thermal energy is not available, or extremly limited on mars?

-Rob

Austin Stanley · 2002-04-01 21:16:01

Well, Uranium and other fissionable isotopes certianly exists on mars. It certianly would be possible to mine them, and refine them there as well eventualy. A CANDU style reactor (uses heavy water as a moderate) could even be used so that refinment would not be necessary.

A solar power tower, and other solar-mechanical systems are also good alterntives to the various nuclear alternatives. Focus a bunch of sunlight on a fluid to heat it up and turn a turbine. Many of the bulky materials could be refined on the surface, it's simple, and can produce a good amount of power-output on a clear sunny day.

Michael Bloxham · 2002-04-02 22:57:20

Researchers in Australia are currently testing a new type of wind turbine. Heres how it works: The device consists of a long tether; anchored to the ground, a helicopter-like turbine, and a small generator. It is launched by feeding power to the small generator, which doubles as a motor. The motor turns the turbine, which helicopters into the atmosphere. Once the tether is taught, and the turbine is at its highest altitude, the motor is turned off and is now kept aloft only by the continual pressure of the jet stream. The turbine is spun by the jet stream, and the power produced is sent back down the tether.

My question is whether or not mars has jet streams. Jet streams are often one-hundred times the speed of surface winds, and are therefore a much better source of wind power

Omer Joel · 2002-05-19 05:16:08

Nuclear power is far more efficient than solar or wind power, especially in the first missions, as it produces far greater amounts of energy per weight unit, and as long as you launch the equipment from Earth, weight would be one of the most important factors. I think that most people tend to exaggerate the risks involved in using nuclear power, as it was used for decades in naval vessels without too many accidents, and as long as the reactor is placed sufficiently far from the Mars base, the main risk to the mission from a reactor accident would be the loss of the power generation capability (and Mars vehicles, structures and suits would be pressurised and protected from radiation anyway, so a small leak from a small, distant reactor will be far less dangerous than on Earth). Ofcourse, by the time a permament Mars base will be built, Fusion power might be possible (I've read estimates about fusion power being available somewhere around 2050, but it's probably inaccurate).

Peter Pevensie · 2002-05-21 06:39:24

I'm a staunch proponent of nuclear fission on Earth (I was a nuclear engineering minor), so as you might imagine I have no problem using a fission reactor to power a Mars settlement. However, I forsee it being a hard sell for earthbound mission planners who have to deal with Earth's political agendas, petty provincialisms, and media-fueled ignorance.

What about constructing solar arrays in Martian orbit and beaming the power down to a settlement via microwaves? I've not done any significant study of the concept, but I know it has been advocated as an alternative energy source for this planet...and with the Martian atmosphere so much thinner than Earth's, I would imagine the efficiencies would be significantly higher there.

C M Edwards · 2002-05-22 12:02:07

I should point out that few to none of the reactors previously launched into space (the numbers are skewed by varying degrees of secrecy) have been capable of more than 10kW, and none exceeding 2kW are known to have lasted more than 6 months.

Check out a rough list of known reactors in orbit here:

http://www.globenet.free-online.co.uk/ianus/npsm1.htm

Solar arrays can be built with these outputs, and with better reliability.

CME

dicktice · 2002-11-20 18:23:21

As for electrical power: Vertical wind-tunnels using Martian atmosphere in stretches of the "chaotic" canyon tributaries, with multistage turbo-electric generators at their bases, driven by the flow of solar heated Martian "air" from beneath low transparent roofs, with guy-wires from the high canyon sides to stay the kilometres-high "chimneys." With enough roof coverage, the accumulated warmth during daytime might be sufficient flow to supply electricity during nighttime. East-west canyon alignment would of course be advisable, and alternative (eg. fuel-cell) power during sandstorms provided for.

Phobos · 2002-11-20 22:01:25

I believe Germany (maybe it was India) did a lot of experiments with solar chimneys to generate power. I never thought about how they could be used on Mars and I think it has possibilities. I just worry about the density of the atmosphere being too low to make it efficient and practical. Even here on Earth with our far more ample supplies of sunlight they still aren't all that efficient. If they could be made efficient though all of that heated air they produce might also make a valuable resource in itself.

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