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An interesting paper on the relative steel and concrete inputs for different power plant types and designs. The values concern the amount needed in tonnes, to produce a MWe of power, taking into account capacity factors. To cut a long story short; wind power plants have appallingly low power density.
http://fhr.nuc.berkeley.edu/wp-content/ … _input.pdf
Focusing on steel mass (tonne)/MWe:
Wind = 450-470 tonnes;
Coal = 90 tonnes;
Nuclear PWR (1970s vintage): 40 tonnes;
Nuclear ESBWR: 30 tonnes;
Nuclear (AHTR): 10-20 tonnes;
Gas turbine (natural gas): 3.3 tonnes.
It will surprise no one reading these figures to know that gas turbines powered by natural gas, have dominated new power plant technology in Europe and the US, for over two decades. The reasons are simple: so long as natural gas remains relatively cheap, the much greater power density of gas turbines makes them the least capital intensive generating system. If we could find natural gas and oxidizer on Mars and access it without too much drilling and pipework, then a gas turbine would probably be the most economical power source for a Martian base. Unfortunately, it is unlikely that we will find such convenient resources on Mars.
The steel mass required for 1MWe of wind, does not include any arrangements made for storage. An energy storage system is essentially a whole other power plant, that eats intermittent electricity as fuel and spits out dispatchable electricity as an output. If the embodied steel requirement is taken to be the same as a coal power plant and a 30% energy loss in storage is assumed; the real embodied steel requirement for wind power is about 800 tonnes of steel per average MWe. This is 20 times greater than the steel requirement of a 1970s PWR; some forty times greater than a Generation 4 HTR.
We are in a desperate race to replace fossil fuels, in the limited time that we have before the EROI of remaining resources is too low to be profitable and before the environmental effects of their release products begins exerting a serious toll on human civilisation. Wind power has fallen in price due to scale economies, and before the cost of storage is taken into account, it may even be competitive with nuclear and fossil fuels in some locations. Although embodied energy and materials requirements are much greater for wind turbines, they are simpler devices, that can be built quickly. After storage is accounted for, wind is very expensive, both financially and in terms of resources.
We clearly need to focus development on options that have some hope of replacing fossil fuel power at an achievable resource cost. If fuel and pollution were not a problem, it is unlikely that we would choose to produce electricity using anything other than gas turbines. Given the restraints that we do have, high temperature nuclear reactors are the next best thing. The barriers to realising these reactors are legal and institutional. They have to do with regulatory requirements that increase build time and costs and the simple fact that there are no established economies of scale or established supply lines for the required components.
By the way, the Three Mile Island accident is just not in the same class as Chernobyl or Fukushima. The release was equivalent to a chest X-ray or two, but spread out very thinly. Could have been worse, but wasn't. The containment actually worked. There might not even have been a meltdown, had the crew not done the wrong things. Stupidity caused this, ultimately. At least it was not too bad.
Fukushima happened because (1) historical not geological records were used for earthquake and tsunami resistance design criteria, and (2) they had nowhere to put the waste but pools in or around the reactor buildings. So here the ultimate cause really was human stupidity, from the get-go.
GW
The point is that even Chernobyl and Fukushima, were small potatoes compared to the effects of fossil fuel air pollution. Perhaps several thousand mortalities against several million per year for air pollution. Our response to both accidents, in terms of large-scale evacuations is disproportionately costly. If the same risk aversion were to be applied to air pollution, we would to evacuate all of our towns and cities on a daily basis. There does not seem to be any proportionality in how human beings deal with risks.
I am labouring this point, because the next thirty years will need very large increases in the use of nuclear power to substitute for depletion of fossil fuel energy. The use of renewable energy is entirely impractical as anything other than a niche solution. After storage, wind and solar will be several times more expensive than present day electricity rates. And industrial civilisation depends critically on cheap and abundant energy.
This BBC report shows that the Chernobyl impact was likely more severe than official figures (a lot of them deriving from the untrustworthy Soviet bureaucracy). The early-death toll could be in the hundreds of thousands across Europe. No one knows, and it's unlikely anyone ever will.
That is absolutely absurd. How do you think these sorts of estimates are arrived at? Do you think these numbers are just pulled out of the air? Radiation contamination maps are used to calculate doserates, which are multiplied by weighting factors. This gives a best estimate of 4000 mortalities. This has quite a lot of provenance behind it as you might notice.
https://www.un.org/press/en/2005/dev2539.doc.htm
If Chernobyl contamination did result in hundreds of thousands of casualties, then by the same logic people in Cornwall, Brazil, Colorado and other high background radiation areas, would be dropping like flies. Yet this doesn't happen.
Lets take a look at a quote from your BBC reference:
"In Ukraine, death rates among these brave individuals has soared, rising from 3.5 to 17.5 deaths per 1,000 people between 1988 and 2012. Disability among the liquidators has also soared. In 1988 68% of them were regarded healthy, while 26 years later just 5.5% were still healthy. Most – 63% – were reported to be suffering from cardiovascular and circulatory diseases while 13% had problems with their nervous systems. In Belarus, 40,049 liquidators were registered to have cancers by 2008 along with a further 2,833 from Russia."
People that were adults in 1986 will have been is their 50's and 60's by 2012. Unsurprisingly, their mortality rate was higher and they weren't in the same good health as they were 26 years previously. Also, these people lived through the poverty associated with the breakup of the Soviet Union.
40,000 cancer cases amongst a liquidator population of 800,000 after 26 years, isn't very surprising in an ageing population. Roughly a quarter of us are going to die this way. In fact, I might have expected it to be higher.
The rest of the nonsense about renewable energy is just that. North Sea wind power is costing 3-4 times UK base electricity rates. Crucially, this does not include the costs associated with backup and storage. As things stand, wind power in Britain is basically gas-turbine power with wind energy used to cut the fuel bill. Energy storage is so expensive that no country is building it on anything like the scale needed to cover wind power lulls.
There is no hope of maintaining developed world living standards using any mixture of wind and solar energy. High living standards are bought at the expense of high energy consumption. This is only affordable so long as energy remains cheap. And intermittent renewable electricity is not going to be cheap, especially after storage is paid for.
Another more anecdotal way of looking at the comparison between relative risk presented by nuclear power and fossil fuel power; is to consider the relative quantity and toxicity of release products. When fossil fuels are burned, they produce particulate matter, partially combusted hydrocarbons, carbon monoxide, nitrous oxide and sulphur compounds. These are fossil fuel release products.
Nuclear power generates waste in the form of fission products, which are the highly radioactive fragment atoms that remain after fission. These fission products are a million times more toxic to human health than fossil fuel release products. But because of the much greater energy density of fission, they are produced in quantities a million times smaller.
Why is nuclear power so much safer? Because we do successfully manage to contain the much smaller volume of volatile fission products safely, most of the time. Only during accidents will nuclear waste be released to the environment. Large releases occur only during severe accidents, which are correspondingly less frequent. This contrasts with fossil fuel power sources, for which meaningful containment of effluent is impractical due to its very high volume. So nuclear power will always be safer. In fact, if we replaced all coal burning power plants in the world with a fleet of Chernobyl-type RBMK reactors, human safety would be substantially improved.
This thread attempts to present a balanced view of the real risks associated with nuclear power, by comparing it to what it has already partially replaced here on Earth: Fossil fuel energy.
The Chernobyl accident presents a baseline for what might be expected from the worst realistically possible single reactor accident. I assert this because a large proportion of fission products was released to the atmosphere due to a complete absence of containment of the damaged reauctor. Whilst very improbable, this outcome could be approached during an accident in a light water reactor if the containment system were to suffer sufficient physical damage.
Scientific estimates of long-term health consequences of Chernobyl vary between 4,000-16,000 early mortalities as a result of radioactive contamination. The World Health Organisation estimate a total of ~9000.
Whilst this is certainly not a trivial outcome, it is useful to compare it to the effects of air pollution from the burning of fossil fuels. In the US, the MIT estimate that 200,000 deaths occur every year due to the effects of fossil fuel combustion.
https://news.mit.edu/2013/study-air-pol … he-us-0829
In Europe, the figure is 500,000 per year.
https://phys.org/news/2017-10-air-pollu … -year.html
In Asia and the Pacific Rim countries, the annual casualty rate runs into millions.
https://www.who.int/mediacentre/news/re … lution/en/
Air pollution kills 30-120 times more people every single year in Europe than the Chernobyl accident did in its entirety. To put it another way, in the 33 years since the Chernobyl accident, air pollution has killed 1000-4000 times as many people. We would need to do very very badly with nuclear safety, for radioactive pollution to come close to the mortality rate that we routinely accept from fossil fuel air pollution. As incredible as it may sound, we would need dozens of Chernobyl nuclear accidents every year in Europe, for the dangers of radiation to come close to what we routinely accept from air pollution. Worldwide, we would need several hundred Chernobyl scale accidents each year, before we could approach global air pollution deaths. Even if every nuclear reactor in the world melted down without containment in the same year, we would actually run out of nuclear reactors before we could get to this level.
Now consider that most nuclear reactors have robust containment systems. In addition, the core melt frequency of 1970s era reactors was about 1 in 10,000 years. Newer reactors with passive safety; are orders of magnitude safer still. Even if humanity relied upon thousands of these passively safe reactors to provide most of its power; decades or centuries are likely to pass before we experience a core melt accident, most of which would result in negligible consequence due to the presence of containment domes. Even at 1970s standards of safety, a world powered by thousands of reactors would not experience a major accident more often than once every few years. Even setting the bar this low, nuclear power is thousands of times safer for the public than fossil fuel energy.
I would therefore propose that there is little rationality in restricting the use of nuclear power on safety grounds here on Earth. The same is true for a Mars mission, fir which the danger of death from nuclear radiation is a negligible proportion of total mission risk.
Kbd512, The outcome of the next election will depend largely upon whether the US is in recession or not. If a recession is avoided before November 2020, then Trump will almost certainly enjoy four more years. If not, then he is toast and the next US president will probably be Elizabeth Warren.
James Howard Kunstler has written an excellent piece that sums up the disgust that many people feel towards a left-wing political system that has lost its way the world over.
https://kunstler.com/clusterfuck-nation/a-hard-rain/
If you want a good picture of where the Dems want to take America, take a look over the pond at the UK. A country without a written constitution, in which a wrong word can land you in prison. The native population are being diluted into minority status, by an influx of a million third world immigrants every year. Voice too much dissent and you may find yourself on a police watchlist. That's assuming that Britain's de facto secret police force, the 'Terror Police' don't decide to break in your door in the middle of the night and bundle you into the back of a van. These things really do happen in Britain. And it is only the US constitution that prevents similar things happening there too.
Two articles from Kris DeDecker's low tech magazine that discuss how a society might live on intermittent energy.
Here are some more of those same topics that are present here
Louis' Solar Power StrategyGoing Solar...the best solution for Mars
Magnox Nuclear Reactors for Mars
NASA and DOE to test kilopower nuclear reactor for space applications
Perhaps imported solar is a better fix for underground agriculture systems when we establish a Martian base. In that case, no backup power is needed as the crops are illuminated by LEDs when the sun is up and illumination levels just follow the day-night cycle. Other equipment can be directly coupled to solar panels as well. It all depends on what the equipment is and if you are only going to use it intermittently anyway. Ideally, it is always more cost effective to operate expensive equipment on a continuous basis. As I have said before, if you build a solar powered propellant plant, it must be 3 times the size of a nuclear powered equivalent to produce the same output per day. Some things really just work better with a continuous power supply. On the other hand, if I need to use a lathe for an hour every day, then I can simply schedule that activity for daylight hours.
Magnox reactors? Those things had enormous carbon moderator blocks and terrible low power density. The UK more or less dropped Magnox as soon as enriched uranium became relatively cheap.
To all posters here on this thread-
We have gone past the point of a "discussion," and ventured into dealing with an emotional argument. One side has attempted rationality and evidence based on engineering and physical science. The other side in this now argument stubbornly clings to a position which only has some passing banter statements to support. Since I started this thread, we need to stop wasting time and electrons; otherwise I'll ask the moderators to lock down any further posting.
Rodger
Granted. This thread was presumably started to discuss the wisdom of Trump's Mars First strategy. That is a worthy topic that is worth debating in my opinion. Whilst Mars is scientifically more interesting and a better choice for long-term colonisation; the moon is cheaper and technically easier to reach. What is more, lunar mining can support manufacturing activities in Earth orbit. We can't really do that with Mars.
I do think it's time to kill this myth of dangerous nuclear power. But it deserves it's own thread.
This thread started out as a discussion of the wisdom or lack thereof, of Donald Trump's decision to focus NASA manned spaceflight efforts towards Mars instead of the moon. It has degenerated into yet another pointless nuclear vs. solar discussion, in which engineers argue for a sensible solution and an idealist argues otherwise because he doesn't like the idea of it. Sorry if I sound obtuse, but that is the truth of the matter.
I find it rather strange that people have to hammer home the need for nuclear power on a planet that receives 43% of Earthly solar flux; temperatures that can freeze human flesh as hard as stone and has dust storms that can block out the sun for weeks at a time. For a human mission you clearly need a very reliable power supply that works all of the time, because you need to breathe and keep warm all of the time.
It is also worth noting that it will cost billions of dollars for every mission that sends men to Mars. For every kg of equipment sent to Mars, the cost will be tens of thousands of dollars. Each day of astronaut time on Mars will cost on the order of $10million. If that astronaut time is used in a way that is sub-optimum due to limitations imposed by Martian weather or Martian night-time; the cost of lost productivity is huge. If you have to include extra mass to meet the needs of energy storage, the cost is huge. If you need to oversize equipment to maintain propellant production rates with an intermittent power supply, the cost is huge. If you are forced to land at equatorial locations, because of limits imposed by your power supply; then you are severely limiting mission flexibility and degrading the value of investment. An investment that runs into billions of dollars per mission.
Is it really logical to incur all of these costs so that we don't have use a technology that some people just don't like the idea of? If we do end up using solar power as the primary energy source for these missions, it will be because nuclear power is simply unavailable. That could happen for political reasons, which have tended to grind new nuclear projects to a halt and push costs through the roof. But under any scenario where we actually have a choice and can develop these technologies at a sensible cost; we will be using nuclear reactors as the primary power supply for Mars missions.
The moon is a far more logical destination in the near future. It is 3 days away instead of six months. We can mine the moon in support of space manufacturing. Mars is a much more expensive destination and there are fewer potential financial returns.
Ultimately, space policy should focus on ventures that have some hope of being financially self-sustaining. Without that, all of our hopes and dreams of human space colonisation will never get very far.
Hmmm. The US has done this so many times, to so many people, that complaining about it happening to you is a sick joke. There has been a huge amount of fuss on the Dem side about possible Russian influence in favour of the Republican party. So what? The Russians no doubt lobby just as other countries do. It is doubtful that the Republicans received as much help from the Russians as the Dems do from the Jewish/Israel lobby. One rule for us; another for the goyum. Of course, the Israeli lobby hate the Russian government and people, for the heinous crime of refusing to allow neoliberal globalists to asset strip their country. The Russians wanted Russia for the Russians and booted the oligarchs out in the early 2000s. And for that they are hated. And given the power of the Zionist lobby in US politics, the Americans have to turn Russia into an enemy to please their masters. Never mind that this has nothing to do with the interests of any but a tiny proportion of the US public.
It looks increasingly likely that the Russians played no part in the 2016 election. But never let the truth spoil a politically convenient lie.
I quite like president Trump and fully understand why he was elected as president in 2016. However random and poorly qualified he may appear to be; he looked like a saint in comparison to his cheating, crimelord opponent. He was prepared to act in the interests of the nation and followed a president that sat on his hands as the Chinese asset stripped his country and allowed millions of third world invaders to swamp his land. He even welcomed it, being a bit of a third-world Muslim sympathizer himself.
Against that backdrop, a well-meaning layman who said roughly the right things and wasn't downright treasonous; had a good chance of being elected. He didn't have to be perfect. He just wasn't quite so bad. And by that modest measure, he has been a successful president. By that measure, a turd in a suit would have been a better president than Hillary Clinton. A turd would not make good decisions either, but it would refrain from making disastrous ones, like open border policy or declaring war on Russia to please the Jewish lobby. I suspect, judging by the absolute heathen that are lining up to face him on the Dem side, that he will win the next election as well. And in the absence of an opponent with a shred of moral fibre, he will fully deserve to win.
The conservatives tend to win in Britain for the same reasons. The people that vote for them know that they aren't getting a good government. But they cling to the hope that they are at least keeping the civilisation wreckers out if power for at least a few more years. In reality, the Tories are every bit as treacherous and vile as their opponents. But for some reason, people continue to vainly hope that they will be better.
So long as people use elections to keep evil out of power, you shouldn't be surprised to have men like Trump running the show. And with Hillary Clinton as the only other choice, you shouldn't feel too sorry about it either.
"Providing a state sponsored safety net is doable and in my view a necessary part of being a civilised society."
I would agree up to a point. The decline and outsourcing of manufacturing from western nations is largely responsible for the rise of an unskilled and poorly paid underclass, who really have no choice but to eek out a meagre existence in poorly paid service jobs. How can anyone serving the till in Walmart be expected to pay hundreds of thousands of dollars to correct a health problem or put their children through college? These people have no hope without state support. If the US still had a strong manufacturing economy that provided abundant well paid jobs, then the situation might be different. But without those jobs, life really is hopeless for a lot of people.
I think Trump understands that, and his attempts to correct it with the trade war are likely to win him the next election, even if they have done little to help in practice. They are not entirely misguided, in a world in which energy and resource depletion are gradually turning capitalism into a zero sum game. If I were a US citizen, I would vote for him. He doesn't have to be perfect to be better than his opponents. And he definitely isn't perfect. But he looks like a knight in shining armour when held up in comparison to the Crime Queen Hillary Clinton. And I suspect that will also be true of whatever creature opposes Trump at the next election. Most people at this point know they aren't going to get a perfect or even a good government. What Trump promised was a government that wasn't quite so bad. And on those limited terms, he has delivered.
Terraformer, you understand the situation well enough. Over the past sixty years, Britain has gradually come under the control of a well coordinated, ruthless, clever and yet thoroughly disgusting group of people; who are bent upon destroying us. We will call them 'Globalists' for the time being.
In the UK, their power was indirect and relied largely upon their ownership of the media until 1994, when Tony Blair, unable to secure enough funding from trade unions due to his free market, neoliberal economic policies; was approached by Lord Levy, who made him a tempting offer. The offer went something like this: 'We give you whatever money you need to fund your party and election expenses and make sure you get a soft ride through the media. In return, we get final say over government policy'. Peter Mandelson was put in place, to watch Blair; to handle any party coordination with the press and to ensure that Blair held up his end of the deal. The results are well documented. The continuing sell-off of UK assets to wealthy 'globalist' investors. Entrenchment of the UK within an increasingly Marxist EU. Devolution was implemented in a deliberate attempt to weaken British nationhood. The rise of mass-immigration and the deliberate weakening of border controls. The demonisation of national ethnic identity and the criminalization of anyone that opposes Marxists concepts of racial diversity too loudly. Nationalist groups that resisted what was happening faced the risk of becoming banned organizations under new anti-terrorist legislation, with their members hunted down and thrown into prison.
You are correct in your assertion that mass-immigration is something that is being done deliberately to breed out the white population. Hate Speech laws are also a deliberate measure to suppress any British nationalist sentiment that might grow to oppose the 'Globalist Blairite' agenda. Jeremy Corbyn had until recently attempted to distance himself and contain this group of people, presumably with the intent of halting their vandalism of Britain. But they remain powerful, with numerous patrons within the media and business community. Corbyn found himself weakened by a propaganda campaign that accused him of antisemitism, which gives some clue as to who and what these people are.
Whether it will be possible for the British people to take back their country from the 'Globalists' is doubtful. Britain has one of the most effective surveillance and state security apparatus ever constructed. And its powers have grown enormously over the past 20 years. Whilst many British people naively believed that anti-terror and surveillance legislation was being extended to protect them from Islamic terrorism; the reality is that these powers are routinely used to oppress domestic nationalists. It is quite certain that this was the intent of the measures in the first place. Any freedom movement, would be discovered and crushed very quickly.
The American people are blessed with a constitution that protects freedom of speech, in theory at least. They also have the right to bear arms. The same people that enslaved Britain are attempting to weaken and abolish these rights. And the same campaign of population replacement is being inflicted upon the Americans. But at least they can (for the time being at least) discuss this problem without being dragged out of their home in the middle of the night by the 'terror police'. In the US, content controls on social media are used to capture whatever manages to get past mass-media indoctrination. But in theory at least, they do have freedom of speech as a democratic right. Not so in the UK. It is difficult to imagine a situation more bleak. Our Globalist masters have created a prison for our people that is far more extensive than anything George Orwell could have imagined. And the longer we remain under its grip, the more the long-term existence of our people is eroded
Civil War 2: https://b-ok.cc/book/892161/745bf6
"I said who and whatis a country for, NOT what is the government for."
A country is a tribe of people, with common ethnicity, embellished by ties of language, religion and culture. But first and foremost, when I talk about being Scottish, English or British; I am talking about a common ancestry that I share with other people living on this island. Without that sort of shared bond, nationhood is meaningless. It is why I am quite pessimistic about the future of the western world, which has gone out of its way over the past sixty to import people into our lands that share none of that. The US, whilst it has always been a fusion of European peoples and cultures, was and is (for the moment at least) essentially a European country. That is what being white in America is really all about. And it is unavoidably something that cannot be shared with all people.
Kbd512, demographics is destiny. That much is unavoidable unless something very 'dramatic' happens. And certain demographics do tend to lean a certain way politically. Human beings are basically tribal; there is no changing what they are. If the past is any predictor of the future, then the US will be a socialist country in 10 years time. And demographics will entrench that position.
It is not a future that I want to see. But the writing is pretty much on the wall. The babyboomer generation, generation X and the millennials; should have had more children and gotten their heads out of the clouds. But the situation is what it is. If you are part of the dwindling number of white Americans at that point, you will need to decide whether you want to spend your remaining years living under a man like Schiff, or instead take up arms and fight for something different. This is exactly why the founding fathers insisted on the right to bare arms. And it is why the Dems want them taken away.
The 10 kw systems that nasa is developing is being design to not melt down and needs no coolant as its self contained with I think salts for the means to radiate heat.
Its the battery capacity that allows for the higher currents as the panels are low current devices. You would use extra batteries to lower the current draw on each to keep them from over heating when under the higher current useages.
That would be a backup system for using surplus methane and oxygen for power and I think its a last resort to out last a dust storm should the sun be totally blocked out for a long period of time. At that time we would be in emergency power useage protocal so as to conserve energy.
Got it. That makes more sense. One could in fact use one of the vehicles to generate small amounts of emergency power from the alternator.
The Martian surface has huge day-night temperature variations. If we could makes solar thermal panels from local materials, it should be possible to store heat and cold from day and night respectively, in tanks of fluid or masses of soil and rock. A sterling engine could run between the hot a cold stores, generating constant power across the day night cycle.
"2. I query whether nuclear power really has such huge logistical advantages. At the very least you need to take two reactors for failsafeness, it's far less flexible and the safety issues cannot be simply waved away."
Not really. Out of all of the mechanical systems that you take with you, the reactor will be most reliable. What it does need, is more than one power generation loop. It has redundancy built into it, but there only has to be one core. I don't understand why solar would be more flexible.
"The meteorological conditions on Mars, leaving aside cold temperatures, are benign compared with Earth. You certainly don't need robust glass insulation."
Wind loadings are lower. Thermal cycles are far more severe. Dust contamination is likely to be a problem. The UV environment is quite challenging.
"3. PV is much better than steady nuclear power for high energy demand work e.g. smelting, should that be required."
That doesn't make any sense to me. I cannot see any scenario in which an intermittent power source would be superior to a 24/7 power source. With high temperature processes like smelters, you ideally want to maintain constant temperature conditions. Thermal cycling is not good for refractory linings. And if you have the monetary and mass investment in a smelter, how is it in any way superior to run it part time?
"With methane-oxygen storage of PV power you can maintain a fairly even electrical input into the propellant production facility."
You are talking about burning propellant in an engine or fuel cell, to make power for propellant production? Am I reading that right?
I am a little sceptical of this whole ultra-lightweight thin-film PV thing. There are hard limits on how thin and lightweight you can build these systems. Here on Earth, we do have thin-film PV solar farms in the MW range. It is the semi-conductor that is thin, not the panels.
Individual PV cells discharge at <1volt and are combined in series to build up a 12-24v open circuit voltage. Some facilities are able to push that higher. But with thin film, output voltage is limited by the extreme thinness of the semiconductor, which must function as insulation between the two phases and will fry and short circuit if you push output voltage too high. So to build up high power levels, you are talking low voltage and high current, which requires thick conductors on the face and backing plates, to avoid excessive resistance losses and thick cables with cells wired in parallel.
On top of this comes the fragility of thin film PV coatings. These are damaged or destroyed by mechanical flexing, abrasion and oxidation and a stiff backing plate (usually glass) is used to keep them flat and a front plate is required to shield out UV and prevent abrasion.
That is not to say that a power system based upon these panels cannot be made to work with a passable power to weight ratio. But estimates I have seen suggest a few 10s watts per kg average power at Mars surface. And that is without any allowance for storage. Using the energy with either no or minimal storage is probably the best idea anyhow; as it allows much superior power-weight on the power supply side, which will generally dominate mission mass. But it does severely limit the productivity of any downstream equipment, as the PV array will only generate large amounts of power about a third of the day at the equator and more or less at higher latitudes, depending upon the time of year. So your propellant plant will either take 3 times longer to produce the same output, or it must be scaled 3 times larger. The same is true if you are using PV powered LEDs for food production. Then there are issues around deploying the PV array; keeping it free of dust accumulation and maintaining survivable levels of power during dust storms.
Nuclear power offers huge logistical advantages, but the development costs are intimidating. On Earth, new nuclear power projects have been rendered unworkable by overbearing regulatory systems and a general lack of established supply lines and scale economies, which collectively push the price of new projects through the roof. These are institutional problems; not engineering and physics problems. But they ruin profitability all the same. No matter how good something has the potential to be, it is always possible to screw it up.
I suspect that Musk took one look at the financial, political and legal minefield that he would have to negotiate to build a space nuclear reactor and decided that it was just easier and more affordable to go with solar based infrastructure, even with all its obvious problems.
This board reflects perfectly the complete polarisation of US politics. The US is now effectively divided between an ageing and largely white rural populace, who want to maintain it essentially as it is; and a younger, largely urban and increasingly non-white population, that want it to become something completely different. There is no compromise between the two. You cannot compromise with someone that wants you gone.
I suspect that demographics are not on the Republican side. Roughly half of all people under the age of 15 in the US is now non-white and this proportion is growing. This demographic tends to be left-leaning, anti-traditionalist and Democrat.
I suspect that the US is heading for another civil war. If the approaching recession is anything like the last, public anger will grow at a time when government is increasingly bankrupt and unable to contain a growing sectarianism. I do not see good things ahead.
I think size is as well as materials they are made of also equate into just a few business models.
Size 100 -150 I think are mine until gone for the purpose of exporting to where the materials can be used.
size 150 upward would be mine out the center to create habitat space for man to have a safe habor in as space cyclers. Sure some of the materials will be needed as insitu use but there my still be some to export. Its this size and quite possibly the unepected that makes doing it possible for much more than rock...
Asteroids in this size range are easier to work with, as upfront investment costs are more affordable and we do not need ISRU to build the first restraining bag. Hence, this is a foot-in-the-door concept. We are not necessarily looking for an asteroid suitable as a Mars cycler in the first instance. We are looking for the asteroid that makes a close approach to a candidate cycler asteroid and is small enough to begin working at minimal start up cost. If an asteroid of this size range is enclosed with an Earth-made bag, excavated materials can be processed into basalt fibre and used to manufacture segments for a larger restraining bag for a larger asteroid. We would put our glass melting vats and weaving machines in tunnels and manufacture a larger bag under habitable conditions.
A 100m diameter stony asteroid, weighs 1.3million tonnes. If 20% of that mass is used to manufacture basalt fibre, then the resulting bag would be sufficient to enclose a 1km diameter asteroid and allow it to be spun up to lunar levels of gravity. The manufacturing and mining can be carried out in habitable environments, making it much easier. Hence, an initial investment of 98 tonnes in a restraining bag for a 100m diameter asteroid, can ultimately allow access to an asteroid weighing a billion tonnes and so on. The orbit of the asteroid could be adjusted to allow regular close approaches of Earth.
Somewhat off topic, this asteroid has perihelion about 0.02AU from Earth orbit, and Aphelion only 0.5AU from Jupiter orbit.
https://en.m.wikipedia.org/wiki/2016_WF9
The asteroid is volatile rich and probably an extinct comet. Its orbital characteristics and composition make it ideal for accessing the Jupiter system, the Trojans and the outer belt.
Unfortunately, Jupiter's year is so long, that we could wait decades for the cycler orbit to line up with the orbits of either Jupiter or its Trojans. This would work if a relatively small team were to travel to the asteroid and use AI, robotics and nanotechnology to transform slowly over a period of decades into a habitat and fuel station. Humans would arrive in large numbers during a close pass between the asteroid and Earth, presumably on the same orbit on which the asteroid makes a close pass of Jupiter. In the decades before, the asteroid is effectively cannibalised into fuel, consumables and reaction mass that can then be used to springboard a large number of colonists into the Jupiter system, or more likely in my opinion, to the ice-rich Jupiter Trojans.
This is a long-term objective because the Trojans are some 5 times further from the sun than Earth. They are good targets for colonisation only after nuclear fusion is mastered.
Mars Global Surveyor (MGS) entered Mars orbit in 1997. It mapped thorium on Mars surface. I've argued to use a thorium reactor for Mars surface facilities, but thorium is an indicator mineral for uranium. On Earth's surface there is 3 times as much thorium as uranium, and 100% of thorium is usable as nuclear fuel while only 0.72% of uranium is the right isotope. This argues strongly to use thorium for a surface reactor, but again thorium is an indicator mineral so that's where you would prospect for uranium.
By the way, Russia is a signatory to the Outer Space Treaty. That treaty bans weapons of mass destruction in Earth orbit or anywhere else in space. Nuclear explosives for propulsion are not exempt, they're banned under that treaty.
The thorium fuel cycle is not nearly as good as it sounds. The significant advantage that it does have over other breeder reactor cycles is that in molten salt mode, reprocessing is not needed - aside from fission product removal from the (already) molten salt. The thorium breeder creates all the U233 it needs insitu, without need for fuel processing. This removes a certain amount of cost; reduces the risk of diversion of fissile materials into weapons programmes and has beneficial effects in terms of reducing contamination of reprocessing equipment.
But there are significant downsides. Firstly, you need a reactor vessel that will reliably contain a complex mixture of molten fluoride salts for the design life of the reactor - 25-100 years. That's a tall order, even using advanced nickel alloys. Heat exchangers need to be immersed in the salt and will typically have short design lives, necessitating a long shutdown period for replacement.
Secondly, the breeding ratio is poor because of all the parasitic losses from dissolved actinides and fission products. That may sound like a good thing from a proliferation viewpoint, but it really isn't a good thing if you want to increase reactor capacity to meet the needs of a rapidly growing Martian economy. The only way to improve breeding ratio is go down a full reprocessing route and adopt a fast reactor design. But then you are essentially building a fast breeder reactor using solid thorium fuel and blankets instead of uranium fuel. There isn't much difference between the two fuel cycles at this point. The uranium-plutonium cycle has better breeding ratio because plutonium yields more neutrons in the fast spectrum compared to U233. And U233 is heavily contaminated with U232, which is a powerful gamma emitter, which makes fresh fuel fabrication and handling very difficult.
Another thing to consider is that a sodium cooled reactor using metallic uranium fuel, can deploy electrorefining in reprocessing, which is far more compact, cheaper and more proliferation resistant than old fashioned oxide fuel treated with nitric acid. You just melt the metal, remove fission products and recast; adding fresh uranium to dilute as necessary and shuffling DU rods into the blanket radially. Unless we face a truly catastrophic shortage of uranium in the future, it is unlikely that any rational cost benefit analysis would opt for a thorium fuel cycle.