Power for a Mars colony

[jeffkruse]

One thing I don’t see being addressed is how we can create power on Mars.  Most people simply say Solar and Nuclear but it’s not that easy.  First, how much power will we need?  Solar and a few RTG’s might work for a small outpost but that’s not enough to grow with.  With solar, how will a bad dust storm affect it?
With RTG’s we don’t have the plutonium now and even if we did up the production of it, it’s really expensive.
Do we have very simple, robust, low maintenance nuclear reactors that don’t weigh 100 tones?

I just don’t see how colonists will smelt iron, make glass, or make really much of anything without lots of power and expanding that power source.

If we had the transportation today, how could we produce power on Mars with today’s proven tech?

[savuporo]

1 First, how much power will we need? 
2 Solar and a few RTG’s might work for a small outpost but that’s not enough to grow with. 
3 With solar, how will a bad dust storm affect it?
4 With RTG’s we don’t have the plutonium now and even if we did up the production of it, it’s really expensive.
5 Do we have very simple, robust, low maintenance nuclear reactors that don’t weigh 100 tones?
6 If we had the transportation today, how could we produce power on Mars with today’s proven tech?

1 Always more than is available

2 Solar can be gradually expanded, including in-situ materials

3 Depends on if and how you clean it. If you have a farm installation, a simple solution is to have an automated maintenance vehicle. There are terrestrial solar farms where a dedicated maintenace robot takes care of adjusting the sunlight tracking, panel by panel , for example

4 Plutonium is not the only possible RTG fuel. Americium-241 is a good candidate

5 No, and it is unlikely to happen sometime soon because of inherent nature of nuclear industry

6 IMO best bet is to invest in in-situ manufacturing of more solar with gradual expansion.  Such scenario has been proposed for lunar development before, see

http://www.niac.usra.edu/files/library/meetings/annual/jun00/433Ignatiev.pdf

[jeffkruse]

3:  I thought dust storms could last months and be planet wide.?  How much light does a bad dust storm block out even before it gets to the panel?

4:  True but I don’t think we have any RTG’s running on Americium right now.  Is this something that could easily be ready and proven in a short time (<10 years), or are there problems that haven’t been solved yet?  Would the costs then go down by a factor of 10 or 100?

6:  How can you smelt metals and make glass with the power from the panels you brought with you?  Doesn’t smelting and making glass use lots of power?  Going from ore to refined metal takes a great deal of power doesn’t it?  What metals are needed for solar panels?

I just can’t see how we can get from 10 people to 100 people without all the power generating equipment coming from earth.

[A_M_Swallow]

On the Moon and Mars the easiest Insitu Resource Utilisation (ISRU) solar power can be to use mirrors to boil water.  Double the amount of steam and a (inefficient) turbine can be made from ISRU materials.

Large mirrors can concentrate sunlight sufficiently to melt metals allowing smelting of say iron.

[Nessus]

Certainly some form of local manufacturing will be needed in the long run. But initially if you are going to bring the power generating equipment from Earth, with a bit of extra fuel you could use solar-power satellites. After all, you've already done the hard work boosting the power equipment into space (from Earth). Obviously there are issues, solar power satellites need beaming equipment, structural supports.

[savuporo]

3:  I thought dust storms could last months and be planet wide.?  How much light does a bad dust storm block out even before it gets to the panel?

I guess thats when you need RTG backup, conserving power, and energy storage systems such as flywheels also produced from in-situ materials

4:  True but I don’t think we have any RTG’s running on Americium right now.  Is this something that could easily be ready and proven in a short time (<10 years), or are there problems that haven’t been solved yet?  Would the costs then go down by a factor of 10 or 100?

Europeans are close to getting one running
http://meetingorganizer.copernicus.org/EPSC2012/EPSC2012-379.pdf

6:  How can you smelt metals and make glass with the power from the panels you brought with you?  Doesn’t smelting and making glass use lots of power?  Going from ore to refined metal takes a great deal of power doesn’t it?  What metals are needed for solar panels?

It does take a lot of power, mostly in form of heat. So you could in theory use solar concentrators for example as your main heat source. Materials depends on what solar panels you want to make, but silicon based ones are a good candidate.
You would likely have to try and produce very low efficiency cells to avoid initially crazy equipment and facility setup requirements equivalent of terrestrial commercial manufacturing. Read the work and research done in SVEC that i linked to above, A. Freundlich, A. Ignatiev published quite a bit around that a decade ago.

[Solman]

 For both the Moon and Mars I vote for space based solar power.

1. A network of orbiting solar power sats can also provide communications and navigation and be scaled up by simply adding more perhaps larger sats.
2. Power is available to mobile vehicles or temporary camps anywhere anytime without them having to carry more than a lightweight, flexible rectenna. Electric surface vehicles would have unlimited range
3. They could in principle be built of local materials and launched but orbital construction using materials derived from Phobos and/or Deimos makes a lot of sense to me.
4. Large concentrator mirrors can cover a much larger area per unit mass in orbit with its lack of gravity and wind loads than ones on the surface.
5. Concentrators can have far lower mass per unit area than flat plate solar cell arrays. When coupled with PV for high concentration levels which have demonstrated 900 Suns at over 40% efficiency; I feel they make an ideal choice for power sats given the fainter sunlight at Mars.

[savuporo]

Certainly some form of local manufacturing will be needed in the long run. But initially if you are going to bring the power generating equipment from Earth, with a bit of extra fuel you could use solar-power satellites...

I have no doubt that pretty much on the first manned landing on Mars, whenever this happens or by whomever, there will be some sort of additive manufacturing device ( i.e., a "3d printer" ) on board.
But yeah - space solar power would be a good complement, the question is can you reasonably do this on Mars with a laser, or are you still constrained to microwave as on Earth.

[DarkenedOne]

NASA and the Mars society has already thought about this considerably.  Just look up Mars Direct.  A small nuclear reactor would be launched and deployed on Mars. 

As far as solar power is concern it is simply not an acceptable option for use as the primary power source on a manned mission to Mars or a manned colony for that matter.  The problem is that at night and during the winter the surface of Mars get extremely cold.  So cold that no machine has survived for very long on Mar's surface without RTGs.  You need a power source that is available 100% of time or your people turn into popsicle. 

In the long run I think nuclear power and solar power will both be competitive. 

[RonM]

Certainly some form of local manufacturing will be needed in the long run. But initially if you are going to bring the power generating equipment from Earth, with a bit of extra fuel you could use solar-power satellites...

I have no doubt that pretty much on the first manned landing on Mars, whenever this happens or by whomever, there will be some sort of additive manufacturing device ( i.e., a "3d printer" ) on board.
But yeah - space solar power would be a good complement, the question is can you reasonably do this on Mars with a laser, or are you still constrained to microwave as on Earth.

Microwaves would be the best choice. It's a cheap and easy. The rectenna is just a wire grid of the appropriate size. Roll the rectenna out over the sand, have the satellite point at it, and you got power. The power beam can be spread out wide enough to not be dangerous.

A laser system would require photoelectric cells at the receiving end and an intense beam. That sounds expensive, impractical, and dangerous to me.

[Burninate]

We certainly do have small-scale nuclear reactors.  We just prefer, generally, to make them bigger, then slather them in lead shielding, then wrap them in a tomb of reinforced concrete, then slap a huge cooling tower next to them, for civilian powerplants.

A nuclear submarine can't exist without a smallish, compact powerplant that is both shielded and human-serviceable - 50-150MwE scale.  We've run smaller reactors than 50MwE occasionally.

https://en.wikipedia.org/wiki/United_States_naval_reactors

One was actually in a fairly similar application - using second-generation nuclear tech and aircraft-mobile parts to power McMurdo Station in Antarctica with 1.5MwE, though we shut that down after ten years when we decided shipping diesel was easier than the safety issues of maintenance in Antarctic winter.

The design for Mars would be only minimally shielded, and located at the end of a several kilometer tether of electric cabling, which it would unwind as it drove away from the landing site on wheels.  I'm not certain what the secondary cooling system would look like, but one of the 4G high temperature designs would allow some measure of radiative cooling, if the Martian atmosphere isn't convective enough.

[Patchouli]

I'd definitely go with a small nuclear reactor for the early power source.

Reliability is the the most important aspect here.
It must work in the winter and during dust storms at close to full output.
Only a reactor can do that.

For later on solar with ISRU methane production can be used to expand output.

[GregA]

We certainly do have small-scale nuclear reactors.  We just prefer, generally, to make them bigger, then slather them in lead shielding, then wrap them in a tomb of reinforced concrete, then slap a huge cooling tower next to them, for civilian powerplants.

Also see http://en.wikipedia.org/wiki/Small,_sealed,_transportable,_autonomous_reactor
A 10MW option might be a good start. Prototype next year though, and I don't like to point to not-yet-ready technology as a solution. Much to risky!

I don't think Solar will be able to offer the power required, though I hope that we end up seeing various technologies tried in separate interdependent settlements. Industrial settlements will need nuclear, while low power settlements can use other options.

(if we're talking about technological PROMISE instead of reality, I'd hope to see Thorium innovation. The concept of a small piece of Thorium able to be safely handled and used to generate power (when hit by a laser) is intriguing.)

[sghill]

It will be nuclear.  No doubts about it.  Some in situ methane (or even peroxide) power generation may exist too, but those resources will take harvesting energy to collect, so there is a trade-off that robs the colony of in situ's potential.

The weight-to-power ratio of solar power means that the cost to get a set number of panels to Mars for a solar field versus sending a reactor will vastly favor the reactor.

Plus, Mars is a pretty dark place.  Most of the photos we see from the rovers are doctored to show normal light levels making it easier to view them.  In reality, the light levels are about early dusk level here on Earth- yet another strike against solar.

Next, the radiation environment on Mars isn't kind to exposed electronics.  Panels are fine on a rover, but a vast field of them is going to have lots of failures, meaning replacement parts shipped from earth and lots of maintenance.  Nuclear can be buried, or at least shielded.

Finally, nuclear gives other benefits such as heat, the potential for water generation, and the ability to utilize nuclear subterrenes to build out the colony.

P.S. by way of disclosure, I owned an institution-scale solar power development company.  I'm generally very pro solar.

[randomly]

You will have to have some baseline power other than solar. Solar just won't cut it. During dust storms which can last for months the atmospheric opacity increases to the point where power from solar panels is only a few percent of normal. This is above and beyond any dust accumulation on the panels.
http://www.nasa.gov/mission_pages/mer/images/20070720.html

RTG power is limited because you can't turn it off and it must have sufficient cooling all the way from it's final assembly through launch, transit and landing. Its combination of thermal and electric power is very handy. It will certainly be used for some applications.

Nuclear is the only compact, reliable, controllable energy source that fits the bill. The large supply of thermal energy will also ease some habitat and infrastructure design options.

Microwave beamed power is not practical due to the enormous antenna sizes required (kilometers across), Laser beamed power is susceptible to the same weather problems as solar panels.

[ncb1397]

It will be nuclear.  No doubts about it.  Some in situ methane (or even peroxide) power generation may exist too, but those resources will take harvesting energy to collect, so there is a trade-off that robs the colony of in situ's potential.

Some researchers at MIT tend to disagree...

With the help of energy specialists from the Massachusetts Institute of Technology (MIT), NASA commissioned a study of how future manned Mars settlements can be powered. Will nuclear generators need to be constructed? Or can solar panels fulfil our proto-colony’s energy needs (regardless of the dust situation)?

Interestingly, if positioned in the correct location, solar arrays might function just as well, if not better, than the nuclear options. Solar panels could provide all the energy a fledgling colony needs.

http://www.universetoday.com/21293/despite-dust-storms-solar-power-is-best-for-mars-colonies/

You will have to have some baseline power other than solar. Solar just won't cut it. During dust storms which can last for months the atmospheric opacity increases to the point where power from solar panels is only a few percent of normal. This is above and beyond any dust accumulation on the panels.
http://www.nasa.gov/mission_pages/mer/images/20070720.html

You don't necessarily need baseline power as long as all situations are covered. For instance, wind power on Mars only works during dust storms. Solar power only works not during dust storms. Together, even though neither is baseline load, both the "dust storm" condition and the "not dust storm" condition is accounted for.

[sghill]

It will be nuclear.  No doubts about it.  Some in situ methane (or even peroxide) power generation may exist too, but those resources will take harvesting energy to collect, so there is a trade-off that robs the colony of in situ's potential.

Some researchers at MIT tend to disagree...

With the help of energy specialists from the Massachusetts Institute of Technology (MIT), NASA commissioned a study of how future manned Mars settlements can be powered. Will nuclear generators need to be constructed? Or can solar panels fulfil our proto-colony’s energy needs (regardless of the dust situation)?

Interestingly, if positioned in the correct location, solar arrays might function just as well, if not better, than the nuclear options. Solar panels could provide all the energy a fledgling colony needs.

http://www.universetoday.com/21293/despite-dust-storms-solar-power-is-best-for-mars-colonies/

 

Yes they may function well if not better, that's not the issue.  The problem is shipping weight and continual replacement, not efficiency when running. 

Consider this as well.  A 3-D printer can make most of the parts for a nuclear reactor.  It can't do much to make a new solar panel.

[Burninate]

The weight-to-power ratio of solar power means that the cost to get a set number of panels to Mars for a solar field versus sending a reactor will vastly favor the reactor.

Plus, Mars is a pretty dark place.  Most of the photos we see from the rovers are doctored to show normal light levels making it easier to view them.  In reality, the light levels are about early dusk level here on Earth- yet another strike against solar.

It will be either a large-scale solar photovoltaic farm (which I'm skeptical that it can't be made fault-tolerant starting with some overcapacity, systematic faults like dust storms & dust accumulation being the main problem) or a nuclear reactor, not a massive bank of RTGs or some kind of exotic chemical or solar thermal solution.  The nuclear reactor (always specify: a safe several kilometers away from the base, where we don't have to care how radioactive it is) would be vastly favored were this Earth, because on Earth secondary cooling is a matter of phase-change of plentiful water into atmospheric water vapor, and convection of our thick mix of nitrox.  That is not the case in space - on the cooling side one generally requires large quantities of radiators, and this increases mass requirements & lowers efficiency substantially.  How much power one can *dump into* the Martian atmosphere and rock efficiently, using minimal mass and no maintenance, is still an open question.  There are varying degrees of problems translating the strategies we would use for this task on Earth, to Mars.

[jeffkruse]

After reading all this I am even more depressed.  Even if we can get to Mars in the next 15 years we won’t have any proven power for more than a handful of people.  If only a few percent of light gets through during a dust storms that last for a long time then solar can’t be counted on.
It has to be nuclear generators and they are not very simple to keep running.  All the other options like satellites transmitting power, Americium in RTG, etc are all still unproven.   

[guckyfan]

Plenty of light goes through a dust storm. Otherwise Sprit and Opportunity would not have survived. There is a reduction and some of the more energy hungry industry might have to stop, but the colony is not in danger.

Also all the landings so far and a possible future colony would be in the lowest lowlands because landing is easier there. Lighting should be much better even during dust storms on the higher plateaus near the settlement site. So better put solar farms there.