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#151 2021-04-14 11:04:57

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

This paper tells us that a 1970s vintage PWR uses about 40te of steel and 90m3 (180te) concrete per average MW of power generation.
https://fhr.nuc.berkeley.edu/wp-content … _input.pdf

Steel has embodied energy of 30GJ/te.  Concrete has embodied energy 1GJ/te.  So that is 1380GJ of invested energy for electric power output of 1MJ/s.  Energy payback time is 1,380,000 seconds, or 16 days.  A 1GWe reactor needs about 30 tonnes of low enriched uranium each year, which will probably be imported from Earth.  If we have to go down the route of using Martian natural uranium, then you can probably cut the whole system power density of the nuclear power plant by half, with an energy payback time of 32 days.

Even in the second case, if we invest 10% of all generated power into expanding the energy supply, then we can double our nuclear power generating capacity every year.  It is over simplistic to look at the situation as a pure net energy machine.  But starting with 1MWe at year zero and doubling every year, we get to 3700MW after 11.85 years.  So, if the Martian colony is given free reign to develop its own nuclear power supply without political interference from Earth, it is possible to achieve a 1 million person city on Mars within fifty years.  Maybe even less time than that.

Given what we have discussed regarding the embodied energy of solar PV power generation, it is clear that it is not possible to use solar power on Mars to manufacture a 3.7GWe power plant sufficient to support a 1million person colony within 50 years.  It will take the solar power plant at least 100 times longer (3200 days) to repay its initial energy investment.  If 10% of its power is invested in building another solar power power plant, then doubling time is 32,000days, or 88 years.  Given the rate at which these things wear out due to radiation damage, it begins to look physically impossible using solar.  If the power plant wears out in 30 years, say, then about 1/3rd of the output of the solar plant must be used simply to build it's own replacement before it wears out.

Last edited by Calliban (2021-04-14 11:09:49)


Interested in space science, engineering and technology.

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#152 2021-04-14 11:16:21

kbd512
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Registered: 2015-01-02
Posts: 4,737

Re: Settlement design

Oldfart1939,

It's a really simple math problem.  The math will only change substantially if battery energy density approaches the energy density of liquid hydrocarbon fuels.  Even if that were to occur, the nuclear solution still weighs less and consumes less surface area or volume.  It turns out that a solution that revolves around producing energy weighs a lot less than a solution that revolves around storing it.

I should also note that the batteries will be even heavier than the 1,000kg figure suggests, unless the goal is to destroy them in less than 1 Martian year from completely discharging them.  That said, I really have tried to concede every possible advantage to the solar and battery solution, but existing technology is what it is.  If I start sizing the photovoltaic array and batteries to deal with the reality of living on the surface of Mars, the solution is going to get considerably heavier.  I've already demonstrated, using simple math, that solar doesn't confer a mass or volume benefit when no wiring is included to connect all of the solar panels together.

The total mass of a practical solar and battery solution to provide equivalent power over equivalent time, will be at least 3 times what it is for the nuclear solution, ignoring the fact that the Lithium-ion batteries won't be operational 20 years hence, unless Depth-of-Discharge is limited to something between 20% and 50% of total capacity.

If we ever build a facility for fuel-reprocessing using all the excess power we're generating for equivalent weight, then the solar solution is hopelessly out-classed, because the KiloPower reactor is designed for a 1% fuel burnup over its 20 year design lifetime, which means 99% of the original energy content remains in the "unburned" fuel.  Once the Martian colonists start re-purposing the fuel from their original 1,348 KiloPower reactors, they have 471,800kg of Uranium to play with, effectively 17 years of fuel at the consumption rates associated with supplying the constant 3.7GWe.  If we devote 2 Starship flights per opportunity to fuel delivery, then we could have a century's worth of fuel stockpiled over 20 years or so.  20 years later, they'll have their own Uranium and Thorium mining, so then we won't even bother to send fuel.

Isn't it amazing how something so energy dense can effectively make a city of a million people, tens of millions of miles from Earth, energy-independent by the time a child reaches adulthood?

At that point, they have the excess energy to diversify their energy sources to include petrochemicals and solar.

We did wood -> coal -> petrochemicals -> nuclear -> solar and wind, on Earth.

There's no known wood or coal or petrochemicals or wind on Mars, so nuclear -> petrochemicals -> solar.

It's about practicality of the solution with available technology, not desire.  I clearly like solar panels and batteries, which is why I own so many of them, but I also recognize their limitations and I have a practical use case scenario for them.  I'm not trying to use them to power my car.

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#153 2021-04-14 16:31:28

RobertDyck
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From: Winnipeg, Canada
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Re: Settlement design

I've tried to stay out of the energy discussion. But yes, Mars Direct included an SP100 nuclear reactor for the ERV. The Hab used solar panels. That means crew never flew with the nuclear reactor. The reactor would be moved to a crater some distance from the ERV as soon as it lands on Mars, and the robotic rover would drop it at the bottom of a crater so deep that there's no line-of-sight from any part of the ERV to the reactor. Neutron radiation, particle radiation, and gamma radiation all travel line-of-sight so this means Mars dirt of the crater sides will provide radiation shielding. The reactor would not be turned on until it was in that crater. Crew in the Hab would be launched next launch opportunity, which is 26 months after ERV launch. The ERV would take an 8.5 month trip to Mars, crew would take a 6 month trip. So crew would arrive 26 - 8.5 + 6 = 23.5 months after the reactor was turned on. And won't board the ERV for return to Earth until the 500 day surface mission is over, so 16.4 months more.

So if you're worried about residual radiation in the ERV from natural uranium of the reactor that was never turned on, realize it had that much time to decay. Besides, fast-and-on isotopes of fission fragments (radioactive waste) is extremely radioactive, but there won't be any of that until after the reactor is turned on. Before it's turned on, the reactor will have uranium. That's very mild radiation. I saw old video of workers loading yellow cake (uranium oxide) into stainless steel tubes to fabricate fuel rods. They used their fingers, while wearing the loose plastic gloves you get with oven cleaner, white lab coat, plastic shower cap on their hair, polycarbonate safety glasses, and a paper filter mask (N95). That's all. So a reactor with sealed fuel elements, in a sealed reactor, which is taken out of the vehicle more than 3 years before astronauts board? Not a problem.

I could give alternate timeline for my mission plan, but it's not much different. Still the reactor would be removed from the ERV more than 3 years before astronauts board.

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#154 2021-04-14 17:06:25

RobertDyck
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Re: Settlement design

Mars Global Surveyor mapped thorium. It's an indicator mineral for uranium. However, why use uranium? Thorium reactors have already been developed. Thorium cannot be used for nuclear weapons, it's reaction is too slow. And it's far more abundant; on Earth 100% of thorium is Th-232 which can be used as reactor fuel, while uranium has only 0.7200% by mass of U-235. And there's 3 times as much thorium in Earth's crust as uranium. It's highly likely that relative abundance on Mars is very similar to Earth.

Thorium reaction: one atom of Th-232 absorbs a moderated neutron to become Th-233. That beta decays with half-life of 22.3 minutes to Protactinium Pa-233. That beta decays with half-life 27.0 days to U-233. That's fissile, it requires a second moderated neutron to split the atom. When uranium splits, it releases on average 3 neutrons. Sometimes more, sometimes less, on average 3. That means a thorium reactor must be careful with neutrons, it can only afford to waste 1/3.

Web site with periodic table. Click an element to get details. Scroll down to "isotopes", then click button for "More isotope and NMR data...", scroll down to "Radiosotope data". Web Elements

As for weapons; yea sure, a spoon can be made into a shiv. Everything can be made into a weapon. You could expose thorium for a brief time, take it out and wait for it to decay to U-233, then refine the uranium. Still, a lot of work. And I don't know how to refine uranium from thorium. I'm sure it's possible, but I don't know how. Still, that means the only way to use thorium as a weapon is to make it into uranium.

One design devised by India is a thorium reactor that loses slightly more neutrons that required to sustain the reaction. A high neutron source is placed on top, such as a small piece of highly enriched uranium. A reflector above the uranium directs neutrons down into the thorium, angled so the reflector can be slowly turned to "stir" neutrons into the main reactor. Neutrons from the main reactor interact with the uranium to keep it going. The uranium is placed on an arm, so if there's a problem the small piece of uranium can be simply lifted off and placed into a shielded container. Once the uranium is away from neutrons of the main reactor, its reaction stops. Without neutrons from the uranium, reaction in the main reactor slowly dies down and stops. So this is a safety device. Since the uranium is simply set on top of the main reactor, you don't have to worry about thermal expansion causing a control rod to get stuck.

NASA JPL map of thorium at mid-latitudes, from Mars Odyssey: (click image for JPL website)
jpegPIA04257.width-1600.jpg

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#155 2021-04-14 17:12:31

louis
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From: UK
Registered: 2008-03-24
Posts: 6,921

Re: Settlement design

I've pointed out the fundamental flaw in this analysis before. PV panels are essentially closed systems. They don't require need regular supplies of material during their lifetime. This is entirely not the case with nuclear power stations which are complex open systems requiring not just regular material supplies but also direct  human management.

So you're engaging in some creative accounting, by not accounting for the lifetime material input.

Price is your best guide to efficiency and material usage. There is no doubt new PV power on Earth in most places is far cheaper than new nuclear - probably by 40-50 cents per KwH. That's not to deny the intermittency problem.


Calliban wrote:

This paper tells us that a 1970s vintage PWR uses about 40te of steel and 90m3 (180te) concrete per average MW of power generation.
https://fhr.nuc.berkeley.edu/wp-content … _input.pdf

Steel has embodied energy of 30GJ/te.  Concrete has embodied energy 1GJ/te.  So that is 1380GJ of invested energy for electric power output of 1MJ/s.  Energy payback time is 1,380,000 seconds, or 16 days.  A 1GWe reactor needs about 30 tonnes of low enriched uranium each year, which will probably be imported from Earth.  If we have to go down the route of using Martian natural uranium, then you can probably cut the whole system power density of the nuclear power plant by half, with an energy payback time of 32 days.

Even in the second case, if we invest 10% of all generated power into expanding the energy supply, then we can double our nuclear power generating capacity every year.  It is over simplistic to look at the situation as a pure net energy machine.  But starting with 1MWe at year zero and doubling every year, we get to 3700MW after 11.85 years.  So, if the Martian colony is given free reign to develop its own nuclear power supply without political interference from Earth, it is possible to achieve a 1 million person city on Mars within fifty years.  Maybe even less time than that.

Given what we have discussed regarding the embodied energy of solar PV power generation, it is clear that it is not possible to use solar power on Mars to manufacture a 3.7GWe power plant sufficient to support a 1million person colony within 50 years.  It will take the solar power plant at least 100 times longer (3200 days) to repay its initial energy investment.  If 10% of its power is invested in building another solar power power plant, then doubling time is 32,000days, or 88 years.  Given the rate at which these things wear out due to radiation damage, it begins to look physically impossible using solar.  If the power plant wears out in 30 years, say, then about 1/3rd of the output of the solar plant must be used simply to build it's own replacement before it wears out.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#156 2021-04-14 17:24:07

SpaceNut
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From: New Hampshire
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Posts: 23,401

Re: Settlement design

They require cleaning and anti static coatings applied to keep them from being damaged....

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#157 2021-04-14 17:36:42

louis
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From: UK
Registered: 2008-03-24
Posts: 6,921

Re: Settlement design

You make some reasonable points.

To reiterate, I am not a fan of the Musk Dream of a One Million City within 30 years or so (actually I read today he was saying this would be possible by 2060 but it probably is a 30 year project in reality, since for the first 4 to 6 years nothing much will be happening apart from basic survival).

But - running with the thought experiment - I agree, whatever energy system is used, this will highly challenging.

The issue I think is really in the first instance is which energy approach using ISRU offers the best prospects.

No surprise I favour solar, but it is certainly a fact that the PV panel production process is now highly automated and could be made even more so if we wish. I think this is critical in being able to supply the energy needs of the expanding city. We are all familiar with lengthy delays on building nuclear power stations on Earth, but PV panel production has been much more reliable.

So, that would be my basic approach, create a PV panel production process that stays ahead of energy demand.

People might not like the idea of a PV array 22 Km by 22 Kms but there is nothing intrinsically impossible about it.

On Mars making PV panels will probably have the same sort of resource investment that making automobiles on Earth does.

And of course that is the other point: I am sure there are lots of things we do on Earth that we won't be doing on Mars. Private automobile production up to 2060 will be very minimal or perhaps non-existent.  We won't be building metalled roads, airports, seaports, or pylons. For 99% of transactions we won't be transporting goods (or people) thousands of miles. There won't be the need for huge amounts of street lighting. We won't be transporting gas or oil in huge pipelines.

All these things are huge energy consumers and on Mars we won't be consuming that energy. Balanced against that we will have to power life support and interplanetary transport. 

Re heat, if you look at the ECLSS document, it's not one of the big energy drains. My understanding is that heat loss is very slow on Mars, owing to the near vacuum.  But certainly it must be the case in a one million person city that (as we see in urban centres on Earth) the heat of the people, machines and processes in such a confined area creates a heat island that also heats people, so the per capita power requirement is much lower.

I was surprised reading the ECLSS document how significant were things like air lock usage - well that will be v minimal in the one million person city.

Unlike PV panels nuclear power stations actively absorb materials throughout their life. I don't know by how much but I would be unsurprised if an average nuclear power station absorb 2 tons a day over 30 years (not including things like water or other coolant).


Calliban wrote:

Importing power supply equipment for a 1 million person city is a tall order, whatever system we use. Kilopower units are optimised for small power requirements. They would definitely be useful for early missions, but aren't something that anyone would even consider attempting to power a city with. Which is why I am looking at Aqueous Homogenous Reactors for meeting those GWatt scale power requirements for a city on Mars. Electric power consumption per capita in the US is 13,000KWh per year. That is equivalent to a constant power of 1.5KWe each. That is electricity- it doesn't cover heating, which is mainly natural gas, or transportation, which is petroleum products. So a 3.7KWe power requirement per capita on Mars may actually be optimistic, especially when you consider the amount of manufacturing that will be going on. I think a fair chunk of the power consumption in Kbd512's estimate is heat, which would be needed to makeup thermal losses in the Arctic temperatures prevalent on Mars. Guess what nuclear reactors produce in great abundance? Heat. Low grade heat at temperatures <100°C is a waste product of nuclear power generation and requires some sort of heat sink. Apparently, it will be useful on Mars.

You keep suggesting that building a power supply using PV panels on Mars is going to be a less labour intensive and easier process than building a nuclear reactor. That doesn't ring true to me. A PV array capable of generating average power of 3.7GW would cover an area of about 100 square kilometres on Mars (assuming no gaps between panels) and would weigh about 1million tonnes for the panels alone. Much of that mass is going to be high grade semiconductor material. Also, you are going to need silver for the panel conductors, large amounts of copper, inverters and transformers for each cluster of PV panels. You are going to need a large mass of batteries for night time energy storage. Storing 16 hours worth of power in lithium-ion batteries would require 250,000 tonnes of Li-ion batteries. Are we going to be making those on Mars as well? These are all materials that must be mined as ores and reduced using energy into metals.

I don't have a precise weight breakdown for what a nuclear reactor based solution would look like. For one thing, it will depend on system design. I could probably work it out if given enough time. But a pressurised water reactor has power density of 80MWth per cubic meter of core volume. That is extremely compact. This link gives an idea of the size of a reactor system needed to generate 1GWe power.
https://www.nuclear-power.net/nuclear-p … nt-system/

Total primary circuit volume is 285m3. That is for the reactor vessel, pressuriser, pipework and steam generators. If we were to squeeze it into a compact cubic geometry, with the equipment occupying 50% of the volume say, it would fit onto a square 8.3m aside, 69m2. We need 4 of those units to generate 3.7GW. So that is 1140m3 of plant, occupying an area of 276m2.  Let's assume that the primary circuit is made from solid steel.  It obviously isn't, but it makes the sums a lot easier.  The mass of 1140m3 of primary circuit would be 8,600 tonnes. I have not included here the mass of the secondary steam plant, which includes the steam turbine and condenser, which are both quite massive items. But even if we triple the total mass to account for that, we get 25,800 tonnes.

So that's 25,800 tonnes of mostly steel vs 1.25million tonnes of semiconductor grade silicon, copper, silver, steel, glass and Li-ion batteries. The difference in mass for both systems is a factor of 50. In terms of embodied energy, the difference will be even greater, because most of the mass of the nuclear plant is steel. These are crude calculations admittedly, but they don't lend much support to the idea that it will be easier and less labour intensive to build solar power plants on Mars instead of nuclear power plants. Just mining the required materials will be a severe challenge.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#158 2021-04-14 19:14:51

RobertDyck
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From: Winnipeg, Canada
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Re: Settlement design

Interesting. The most concentrated thorium on Mars is Acidalia Planetia, second is Utopia Planetia. These are the lowest spots of the dried-up ocean basin. That implies thorium and uranium were washed into the ocean, and ended up in the last parts of the ocean to dry up. Salt deposits should also be here. One resource that a Mars settlement would require is potassium fertilizer for greenhouses. On Earth the most plentiful potassium fertilizer is potash, a form of potassium salt. This is found where salt water bodies completely dried up. When large seas dry up such as the Great Lakes or Mediterranean, both millions of years ago, that leaves layers of salt. Mars should have the same layers. Potassium map of Mars shows a high concentration in Acidalia Planetia. So this would be an ideal location to mine for both thorium and potassium.

Also a good idea not to build a major settlement here. Don't build on the planet's largest radioactive deposit.

NASA JPL map of potassium at mid-latitudes, from Mars Odyssey: (click image for JPL website)
jpegPIA04255.width-1600.jpg

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#159 2021-04-14 19:27:49

kbd512
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Registered: 2015-01-02
Posts: 4,737

Re: Settlement design

Louis,

Speaking of "creative thinking"...

There is no such thing as a multi-GigaWatt generation station of any kind that is a "closed system" or "maintenance-free".  They do maintenance on the Bhadla array every single day.  They do maintenance on wind turbines every single day.  Even though individual units may only be serviced once per month or two, every single unit in the array is serviced on a routine basis.  The solar panels on my roof that require no routine maintenance are around 75 pounds per panel and require two people to lift one.  Utility-scale batteries are not maintenance-free.  Methane SOXE fuel cells are not maintenance-free.  Cryogen plants are not maintenance-free.  Any assertion to the contrary is utter nonsense.  All I want to see is one or two assertions that agree with basic math or an assertion that agrees with basic observation of the real world.

Oh, by the way, that ultra-lightweight backer board that I proposed using, the high-modulus Today T1000G Carbon Fiber is around $100 per square meter.  That assembly, minus any labor, will be around $500 in materials (at wholesale prices for the high-modulus cloth), so $5B (five billion dollars) in backer board alone, for each Bhadla you construct.  That's why most high-modulus cloth gets used in commercial aircraft construction.  There are few other finished goods where the weight reduction justifies the cost.  Basically, the backer boards will cost more than three times as much as the largest solar array on Earth, before we purchase the first wafer of Silicon or the first strand of Copper wire.  Given that we're already spending that much to keep the panels rigid enough to prop them up with a mound of dirt, why not splurge on 33% efficient Silicon from FullSuns, in order to reduce the truly enormous size of this array?

Absolutely everything we've sent to Mars thus far, solar or nuclear powered, has been a custom hand-built, one-of-a-kind robot with no remotely comparable Earth-bound analog.  There are no multi-billion dollar hand-built solar or nuclear powered rovers on Earth using gold-plated electrical connections that crawl around a few meters every day to take pictures and soil samples.

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#160 2021-04-14 19:57:16

SpaceNut
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From: New Hampshire
Registered: 2004-07-22
Posts: 23,401

Re: Settlement design

Noah I am sure you read the ISS could yield empirical data the design as its a working known level of values for power, water, recycling, food levels required, waste removal ect but we also have another example that is biosphere 2 to which simular data points can be garnered from. The will both point out that we will always need more energy as we add in things that they are not doing ex growing food, manufacturing the location we will live in, making fuels and oxygen, mining water and sucking in the mars atmosphere come to mind.

https://en.wikipedia.org/wiki/Biosphere_2

https://energy.arizona.edu/rd/biosphere-2

https://biosphere2.org/research/themes/ … ainability

Mars will need this and more to work
https://www.wired.com/2009/04/biospheresci/

Not sure of the phase time frame but in order to do what is needed in the phase 1 you would have needed to send the materials or cargo, equipment ect the proceeding cycle so that its already there for the arriving crew to make use of. then during phase 1 you are sending the materials for the arrival of phase 2 crew ect....

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#161 2021-04-14 22:20:03

RobertDyck
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From: Winnipeg, Canada
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Re: Settlement design

SpaceNut,

I have to caution anyone talking about Biosphere 2. That project was idealistic. They believed the biosphere had to duplicate several if not all human biospheres. That's not the case. We will need greenhouses, to grow food and non-food resources. For example, growing bamboo for construction material such as flooring, or industrial hemp for fibre. There are many uses for hemp, including clothing and paper. However, notice I'm emphasizing agriculture, not duplication of wild biomes. The Biosphere 2 project provided a lot of valuable data. For example, they carefully calculated oxygen production and consumption, but decided to use desert sand with twigs instead of imported black soil. That resulted in bacteria that broke down cellulose of the twigs consuming oxygen. They forgot to include that bacteria in their oxygen consumption calculations. This resulted in insufficient oxygen for crew. And their bean crop was supposed to provide majority of their protein, but that bean crop developed a blight. They tried to eliminate the blight several times, but it kept coming back. This resulted in malnutrition for crew. And trees had a problem with branches and entire tree limbs just falling off. Turns out trees require wind to stress them, to stimulate sufficient growth.

Potted plants in large public spaces not only look nice, but help clean the air. Sewage treatment can be done via grey water sewage processing, or a composting toilet. The Biosphere 2 project did a lot of good work, a lot of research. However, I disagree with the concept of trying to duplicate biomes.

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#162 2021-04-15 03:29:57

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

louis wrote:

To reiterate, I am not a fan of the Musk Dream of a One Million City within 30 years or so (actually I read today he was saying this would be possible by 2060 but it probably is a 30 year project in reality, since for the first 4 to 6 years nothing much will be happening apart from basic survival).

It would be a huge industrial effort and the total mass of a city capable of supporting a million people on Mars, runs into many millions of tonnes.  Shipping those materials from Earth is clearly an unaffordable expense, not just for Musk, but for the world's leading financial institutions.  So much of what is needed, including power supply, needs to be made on Mars.  That means reworking local materials into products we need, using energy.  It also means using the output of an initial imported power supply to make copies of itself, as well as all the other stuff.

Materials and products have what is known as 'embodied energy'.  This is statement of the energy that needs to be embodied to make them.  On Earth, virgin steel costs about 30GJ/tonne.  It is about the cheapest industrial metal in terms of both money and embodied energy.  Concrete costs about 1GJ/tonne.  You may notice that we use a lot more concrete than steel in our society.

To build up a city of 1 million people, it will take time.  You can model the development in simple terms as an energy investment process.  Each year, we put some of the energy we are producing in consumables needed to keep people alive.  We also need to invest energy into repairing and replacing existing infrastructure, including energy infrastructure.
Those are the things we need to do simply to stand still.  The energy that is left over we can invest in building new infrastructure and new power supply, so next year we have more infrastructure that can support more people and a bigger power supply as well.  The next year, the cycle begins again.  So really, growth rate is a function of surplus energy divided by the energy cost of the infrastructure you are building. This describes the physics of a growth process.  It is how human society has managed to grow from humble beginnings, into the industrial behemoth that it is today in just a couple of centuries.  It was all because of the high net energy allowed by the use of fossil fuels.  Essentially, the high power density of fossil fuel infrastructure meant that even after paying the energy cost of building that infrastructure and whatever energy we needed to invest in the stuff we needed to survive each year, there was lots of surplus to invest in new infrastructure.  Hence, growth was rapid.

The doubling time figures that I presented in the previous post are idealised cases.  They represent the physical limit of what can be achieved by an energy source if all other factors are there to support it.  In this idealised situation, in which 10% of energy produced is used to construct new energy sources, nuclear power reactors would have a doubling time of about 1 year.  In the case of solar PV, the energy payback time for the plant and batteries appears to be about 8 years.  So diverting 10% of harvested energy into building new energy products is unlikely to be capable of even replacing the existing solar power plant before it wears out.  We would need to use at least 30% of the solar plant energy output, just to keep power output constant in this case, far less expand power supply or build anything else.  That's 30% just to stand still.  And it doesn't stop there, because we obviously have other infrastructure than requires energy investment to maintain and replace and the energy cost of essential consumables.

Now to the point of nuclear power plants consuming materials as they operate.  A 1GWe PWR consumes 30 tonnes of 5% enriched uranium dioxide fuel each year.  So a 3.7GWe power supply implies that 111tonnes of new fuel must be imported from Earth or manufacture on Mars each year.  That works out at 111grams per person, per year, or about 8kg per person across their whole lifetime.  In the total import mass budget for a Martian colony, you could easily lose the nuclear fuel that we will need in rounding errors.  It is a very small amount of material.

To summarise: Using native constructed nuclear power reactors, Musk's ambition is possible, though clearly it is still quite difficult.  It requires the development of a parallel manufacturing economy.  Using solar alone, the physics is telling us that it really isn't possible to do what he is proposing.  From what I can see of early mission power requirements for propellant production and life support, a solar only solution is possible, but rather limiting due to system mass and involves additional risks.  As soon as native manufacturing is employed to turn native materials into new infrastructure, the high embodied energy of solar power systems is extremely limiting, to the point where it doesn't seem to be at all workable.

That is my conclusion having estimated the embodied energy of the respective systems and having employed a simple energy-based growth model.  I don't expect you to like it.  You can pick through the data and develop your own growth model if you like.  But ultimately, there is no point pretending that reality is different from what it is.  Optimistic assumptions and sophistry, may keep internet discussions rolling on for longer.  But they won't change the reality on the ground.

Last edited by Calliban (2021-04-15 04:12:07)


Interested in space science, engineering and technology.

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#163 2021-04-15 05:13:03

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

As an addendum to my previous post.  There seems to be some confusion about labour productivity and what that actually means in a real economic system.  Labour productivity is the monetary value attached to the amount of work that a human being can perform using the skills and tools at his disposal in one man-hour.  There are many factors that will determine how productive any specific individual will be.  But essentially, ever since human beings began using tools, productivity has been about using tools as a channel for work energy in the reworking of matter.  Since the beginning of the industrial revolution, we started using artificial energy, to further magnify the amount of work that an individual can do, as improved scientific understanding allowed us to invest energy in new tools that allowed the channelling of artificial energy.

Let me illustrate the point with the example of a man whose job it is to dig holes.  His productivity is measured by the volume of material he can dig out each day.  Nature imposes ultimate limits on what is needed to shift dirt.  We need to overcome friction when digging, we need to lift dirt out of the hole against Earth gravity and then overcome more friction carrying it to where we pile it up.  So regardless of what technologies are at his disposal, there is going to be a minimum energy cost associated with digging.  New and more efficient tools allow this limit to be approached but never exceeded.

Using no tools other than his own hands and scratching away at the dirt with his fingers, his productivity is clearly quite low.  The energy at his disposal is limited to what his muscles can provide and without tools, the efficiency with which he can apply it to lifting dirt is limited.  The first tool we can give him is a spade.  This allows him to dig with reduced friction and allows more pressure to be applied per unit area.  This dramatically improves the efficiency with which he can apply the limited power output of his muscles to shifting dirt.  But the rate of work (I.e dirt shifted) is still limited by the power output of the man's muscles.  We just provided a more efficient way of exerting that power, moving him closer in terms of efficiency to the physical limits of energy invested per tonne of dirt moved.  Energy had to be invested in making that tool.  Some will be invested in maintaining it and eventually in replacing it.

Now suppose we give that man a steam shovel.  With it, the man can dig far more dirt per hour.  The energy cost of shifting each tonne of dirt hasn't changed.  But we have now leveraged the man's own work energy, using a tool that exploits artificial energy.  The steam shovel burns coal to raise steam, which is then used to generate mechanical work.  We invested artificial energy to make the steam shovel, to reduce iron ore into steel, to melt it, hot roll it and cut and press it into mechanical parts.  We then used more labour and energy to build it from those parts.  Using the shovel, our worker is able to transform the stored energy in the coal into work energy shovelling the dirt.  If we gave him a steam shovel twice the size, he could shovel dirt at twice the rate, but would also burn coal at twice the rate.  His productivity is what he can produce by using his own labour, magnified by artificial energy direct through tools.

Now suppose we assume that technology has improved.  We now give the man a diesel powered digger.  It is smaller than the steam shovel, yet can do the same amount of work per hour.  It has lower embodied energy.  Because it is lighter and powered by an IC engine, it is more efficient.  The same amount of chemical energy can now be leveraged to do more work than before, because technology has allowed efficiency to improve.  But note that there are physical limits here.  The amount of dirt that can be dug per man hour is still a function of the power applied to the task multiplied the efficiency with which that power is applied.

So in summary: Labour productivity is a function of the amount of supplemental energy that a worker can access per hour, multiplied by the efficiency with which he can use it to perform a valued task, which involves the use of energy to rework matter.  The efficiency and his ability to harness the available energy, depend upon the tools at his disposal and his knowledge in being able to use them.  Nature sets limits in terms of how much work can be performed per unit energy that is used.  Those limits can be approached, but never exceeded, by using better tools (technology) and by training the worker to use them.

This is why the economy is fundamentally an energy system.  And the rate at which it can expand depends upon the rate at which it can expand its energy supply.  This is in turn limited by the amount of surplus energy available and the energy cost of new energy equipment.  New technology changes the tools at hand.  It may be possible to reduce embodied energy required using new manufacturing techniques or boost energy return by improving the efficiency of the energy producing device.  But nature imposes physical limits here as well.  Those limits apply regardless of what technology we find at any point in the future.


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#164 2021-04-15 06:20:33

tahanson43206
Moderator
Registered: 2018-04-27
Posts: 7,676

Re: Settlement design

For Calliban re #163

SearchTerm:Productivity of labor with respect to energy
SearchTerm:Labor productivity analysis Calliban Post 163
SearchTerm:Hole digging of Calliban Post 163

The analysis you provided illustrates the use of intelligence to improve the efficiency of operations of a specific kind.  The productivity of a Nation ** must ** include applied intelligence, and in your other posts have I often seen an other acknowledgement of that fundamental explanation why some Nations are much more wealthy than others.

However, more than intelligence and energy are involved, and I ** think ** you and others here have discussed the advantages and disadvantages of various social organizations to harness intelligence to harness energy to achieve results.

We are in Settlement Design, and this conversation seems (to me at least) to be a good fit for Noah and his team to consider.

The videos from last year's Mars Society Convention on settlement (in that case the 1,000,000 person city) often include social organization as a design criterion.   

(th)

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#165 2021-04-15 07:26:36

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

tahanson43206 wrote:

For Calliban re #163

SearchTerm:Productivity of labor with respect to energy
SearchTerm:Labor productivity analysis Calliban Post 163
SearchTerm:Hole digging of Calliban Post 163

The analysis you provided illustrates the use of intelligence to improve the efficiency of operations of a specific kind.  The productivity of a Nation ** must ** include applied intelligence, and in your other posts have I often seen an other acknowledgement of that fundamental explanation why some Nations are much more wealthy than others.

However, more than intelligence and energy are involved, and I ** think ** you and others here have discussed the advantages and disadvantages of various social organizations to harness intelligence to harness energy to achieve results.

We are in Settlement Design, and this conversation seems (to me at least) to be a good fit for Noah and his team to consider.

The videos from last year's Mars Society Convention on settlement (in that case the 1,000,000 person city) often include social organization as a design criterion.   

(th)

Yes.  At a societal level, we have the ERoEI of the energy sources.  This constrains the maximum possible rate at which energy supply (and the accumulation of infrastructure and production of goods) can expand if every other factor of production is perfect.  It kind of sets a fundamental limit at that point in time.

The ERoEI is not set in stone forever.  It can change if the energy source becomes more efficient or if the embodied energy requirements can be reduced with better design.  But there are fundamental limits imposed by nature and engineering trade offs are used.  The efficiency of a nuclear reactor depends primarily on the temperature achievable in its working fluid, which is limited by the melting point of the fuel and the phase change properties of the working fluid.  New fuel and new power generation cycles may boost efficiency.  That is technological development.  But there are natural limits.  There are limits imposed by melting point, material strength at high temperatures and erosion.  These sorts of problems set fundamental limits on how efficient we can ever make a heat engine.  The efficiency of a solar panel depends on other factors.  It becomes more efficient using extra junctions which can be tailored to light of different wavelengths.

In both cases, the innovations that improve efficiency may also increase embodied energy (and cost), pushing ERoEI back down.  This is where engineering trade off becomes important.  In both cases, nature imposes limits on the maximum possible efficiency and minimum possible embodied energy.  Thin film PV materials need to be thick enough to avoid breakdown under the panel voltage.  Using lower voltage reduces the necessary thickness, but increases resistance losses.  So a trade off is reached.  The trade off may change over time allowing better performance, but there will be natural limits that it cannot surpass.  We may discover a room temperature superconductor in the future allowing much lower panel voltage and thinner films for example.  But that fantastic new material will have current saturation limits.  Again, an insurpassable natural limit.

On the energy consumption side of things, technological innovation can reduce the scale of energy investment needed.  We used to make steel entirely in blast furnaces, in which a lot of energy was carried away by furnace gas and wasted.  Now we have electric furnaces, in which the heating process is close to 100% efficient.  Carbon monoxide gas passes over hot iron oxide reducing it to metallic iron.  But note that there are fundamental lower limits to how much energy is needed.  We need to heat the iron oxide to 1600°C and the chemical reaction requires a quantity of reducing gas that cannot be reduced beneath a certain point.  There are fundamental lower limits to how much energy is needed to carry out processes.  Efficiency is not something that can go on increasing ad infinitum.  In many cases, we are pushing fundamental limits already.

The energy limits of an economy can be thought of as fundamental upper bounds on what is physically achievable at this time and at any point in the future, if every other factor were perfect.  Within those limits, other constraints, such as human factors, social organisation of labour, varying human intelligence, etc, will place lower limits on what society can achieve at that time and place.  The human limits are always smaller than the energy defines limits at any given time and technology set.  And the achievable energy limits at any given technology set, are always bounded by fundamental limits imposed by nature.  For example, we can presently produce virgin steel for 30MJ/kg.  But the electrochemical potentials of iron and oxygen and the energy required to melt iron, tell us that we will probably never be able to produce it for very much less, regardless of any technology we discover in the future.


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#166 2021-04-15 07:48:37

louis
Member
From: UK
Registered: 2008-03-24
Posts: 6,921

Re: Settlement design

This is why the EROI is invalid as the key analytical tool for the efficiency of energy systems

If you have two scenarios:

A. It takes 100 people using 10 units of energy to produce 100 units of energy. The EROI is an impressive 10 to 1.

B. It take 1 person using 10 units of energy to produce 12 units of energy. The EROI is a pathetic 1.2 to 1

But when you look at the amount of energy being produced per person you can see that with Scenario B 100 people can produce 1200 units of energy, way more than the 100 units produced by 100 people under Scenario A.

Now of course this is a very simplistic illustration but something like this is happening before our eyes today with Scenario A being fossil fuels and nuclear power and Scenario B being PV and wind power. We aren't quite seeing the full impact yet because PV and wind power energy input are very much up front and translate into a high initial investment. Furthermore, the absence of effective energy storage systems is suppressing investment in the technology. But we are getting closer all the time to effective energy storage.

It makes much more sense as to think of the economy as a labour and energy system, not just an energy system.

This was why in the 18th century Japan had arguably the most advanced economy in the world. It had a city with over 1 million people long before London. It had a highly complex economy with numerous specialised workshops. It was probably the most literate society on Earth. But it had no steam power. The energy systems were basically wood burning and animal power.

How did it manage to be so advanced? Well it had a very large food surplus thanks to improvements in rice production. This enabled Japan to free people from agricultural labour and direct them into industry and education. Of course, food is energy. But that just confirms, it's the interplay of labour and energy which are important.

Looking at Mars, I think for the first few decades labour is going to be in very short supply, given everything that needs to be done in building up the economy. So, advanced automation and robotics will be a necessary feature of the economy. Mars won't have many cooks, or waiters or cleaners or bus drivers or taxi drivers or indeed - in comparison with Earth - energy workers.


Calliban wrote:

As an addendum to my previous post.  There seems to be some confusion about labour productivity and what that actually means in a real economic system.  Labour productivity is the monetary value attached to the amount of work that a human being can perform using the skills and tools at his disposal in one man-hour.  There are many factors that will determine how productive any specific individual will be.  But essentially, ever since human beings began using tools, productivity has been about using tools as a channel for work energy in the reworking of matter.  Since the beginning of the industrial revolution, we started using artificial energy, to further magnify the amount of work that an individual can do, as improved scientific understanding allowed us to invest energy in new tools that allowed the channelling of artificial energy.

Let me illustrate the point with the example of a man whose job it is to dig holes.  His productivity is measured by the volume of material he can dig out each day.  Nature imposes ultimate limits on what is needed to shift dirt.  We need to overcome friction when digging, we need to lift dirt out of the hole against Earth gravity and then overcome more friction carrying it to where we pile it up.  So regardless of what technologies are at his disposal, there is going to be a minimum energy cost associated with digging.  New and more efficient tools allow this limit to be approached but never exceeded.

Using no tools other than his own hands and scratching away at the dirt with his fingers, his productivity is clearly quite low.  The energy at his disposal is limited to what his muscles can provide and without tools, the efficiency with which he can apply it to lifting dirt is limited.  The first tool we can give him is a spade.  This allows him to dig with reduced friction and allows more pressure to be applied per unit area.  This dramatically improves the efficiency with which he can apply the limited power output of his muscles to shifting dirt.  But the rate of work (I.e dirt shifted) is still limited by the power output of the man's muscles.  We just provided a more efficient way of exerting that power, moving him closer in terms of efficiency to the physical limits of energy invested per tonne of dirt moved.  Energy had to be invested in making that tool.  Some will be invested in maintaining it and eventually in replacing it.

Now suppose we give that man a steam shovel.  With it, the man can dig far more dirt per hour.  The energy cost of shifting each tonne of dirt hasn't changed.  But we have now leveraged the man's own work energy, using a tool that exploits artificial energy.  The steam shovel burns coal to raise steam, which is then used to generate mechanical work.  We invested artificial energy to make the steam shovel, to reduce iron ore into steel, to melt it, hot roll it and cut and press it into mechanical parts.  We then used more labour and energy to build it from those parts.  Using the shovel, our worker is able to transform the stored energy in the coal into work energy shovelling the dirt.  If we gave him a steam shovel twice the size, he could shovel dirt at twice the rate, but would also burn coal at twice the rate.  His productivity is what he can produce by using his own labour, magnified by artificial energy direct through tools.

Now suppose we assume that technology has improved.  We now give the man a diesel powered digger.  It is smaller than the steam shovel, yet can do the same amount of work per hour.  It has lower embodied energy.  Because it is lighter and powered by an IC engine, it is more efficient.  The same amount of chemical energy can now be leveraged to do more work than before, because technology has allowed efficiency to improve.  But note that there are physical limits here.  The amount of dirt that can be dug per man hour is still a function of the power applied to the task multiplied the efficiency with which that power is applied.

So in summary: Labour productivity is a function of the amount of supplemental energy that a worker can access per hour, multiplied by the efficiency with which he can use it to perform a valued task, which involves the use of energy to rework matter.  The efficiency and his ability to harness the available energy, depend upon the tools at his disposal and his knowledge in being able to use them.  Nature sets limits in terms of how much work can be performed per unit energy that is used.  Those limits can be approached, but never exceeded, by using better tools (technology) and by training the worker to use them.

This is why the economy is fundamentally an energy system.  And the rate at which it can expand depends upon the rate at which it can expand its energy supply.  This is in turn limited by the amount of surplus energy available and the energy cost of new energy equipment.  New technology changes the tools at hand.  It may be possible to reduce embodied energy required using new manufacturing techniques or boost energy return by improving the efficiency of the energy producing device.  But nature imposes physical limits here as well.  Those limits apply regardless of what technology we find at any point in the future.


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#167 2021-04-15 08:38:41

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

louis wrote:

This is why the EROI is invalid as the key analytical tool for the efficiency of energy systems

If you have two scenarios:

A. It takes 100 people using 10 units of energy to produce 100 units of energy. The EROI is an impressive 10 to 1.

B. It take 1 person using 10 units of energy to produce 12 units of energy. The EROI is a pathetic 1.2 to 1

But when you look at the amount of energy being produced per person you can see that with Scenario B 100 people can produce 1200 units of energy, way more than the 100 units produced by 100 people under Scenario A.

Now of course this is a very simplistic illustration but something like this is happening before our eyes today with Scenario A being fossil fuels and nuclear power and Scenario B being PV and wind power. We aren't quite seeing the full impact yet because PV and wind power energy input are very much up front and translate into a high initial investment. Furthermore, the absence of effective energy storage systems is suppressing investment in the technology. But we are getting closer all the time to effective energy storage.

It makes much more sense as to think of the economy as a labour and energy system, not just an energy system.

This was why in the 18th century Japan had arguably the most advanced economy in the world. It had a city with over 1 million people long before London. It had a highly complex economy with numerous specialised workshops. It was probably the most literate society on Earth. But it had no steam power. The energy systems were basically wood burning and animal power.

How did it manage to be so advanced? Well it had a very large food surplus thanks to improvements in rice production. This enabled Japan to free people from agricultural labour and direct them into industry and education. Of course, food is energy. But that just confirms, it's the interplay of labour and energy which are important.

Looking at Mars, I think for the first few decades labour is going to be in very short supply, given everything that needs to be done in building up the economy. So, advanced automation and robotics will be a necessary feature of the economy. Mars won't have many cooks, or waiters or cleaners or bus drivers or taxi drivers or indeed - in comparison with Earth - energy workers.

Half true.  You can think of EROI as setting the upper limits of the possible.  It is not an invalid concept, it is more that there are other constraints beneath it.

Your description of the difference between labour productivity in producing the two energy sources assumes that the processes involved in making them are completely different and you need ten times more people to build an equivalent nuclear power plant.  But both processes involve manufacturing metal components, digging holes and pouring concrete.  The same sorts of industrial processes are used to build and assemble solar, wind and nuclear power plants.  They are all primarily steel and concrete, with minor additions of semiconductor silicon, copper, aluminium, glass etc.  The productivity per unit product should be about the same.

So the question is why is Hinkley C, say, not forecast to produce electric power far more cheaply than North Sea wind turbines, given that it far more compact?  One reason it that nuclear build capabilities in the UK and US were allowed to die in the dash for gas in the 1980s - 2000s.  It seemed to be an era in which it was fashionable to treat short term advantages as if they were permanent and generally not care about the future.  Building a nuclear reactor now means establishing whole new industries, to supply key components.  In some cases, the skillsets no longer exist in the UK and need to be reestablished.  So building the first few units is going to be expensive.  It will be a slow process of rebuilding the industry.  Subsequent units will be cheaper.  In France at the height of their build programme in the 1980s, nuclear power plants were amongst the cheapest generating capacity in the world and they were building 2-3 units per year.  That is the sort of industry base that we need to establish for our Martian colony.

The situation for fossil fuels is different.  The ERoEI is actually declining as high grade oil and gas reserves are depleted.  Combined cycle power plants have partially mitigated that downward trend thanks to their extremely low capital cost and high efficiency.  But ultimately, the fossil fuel industry is going to shrink, not because of peak demand, but because remaining oil and gas deposits will not be profitable at prices that consumers can afford.

There are other market distortions that are muddying the water and give misleading impressions of what will be sustainable in the future.  For the past 12 years, interest rates have been less than zero when adjusted for inflation.  This effectively means that capital costs are zero.  That is the point of having low interest rates, it is supposed to stimulate investment and make investment more affordable.  But it also destroys effective returns on investment.  If pension funds are earning close to zero return, how big are those pensions going to be in 30 years time?  And it tends to result in rapidly inflating debt.  Why not borrow millions, if the effective interest rate is zero?  That is exactly what many zombie companies have done.  We are now in a situation where interest rates cannot rise without putting large parts of the economy into receivership.  The problem is, the longer they remain low, the more we are stealing from the future.

You may notice that the renewable energy boom didn't start until 2008?  First there was the spike in all energy prices due to the peaking of world conventional oil production.  Oil prices remained over $100/barrel until 2014.  You would expect that to stimulate interest in other sources of energy and it did.  Then interest rates dropped to zero and have remained there since.  Obviously, that makes highly capital intensive products like wind turbines very affordable, so long as interest rates don't rise above zero.  The question is, what happens when they finally have to?

So to summarise, nuclear build capability died in the UK in the early 90s.  It is now struggling to be reborn.  With North Sea oil and gas essentially gone, its success in doing so will determine whether we have a future as an industrial nation.  On the other side of things, zero interest rates are making wind and solar projects look a lot more affordable than they really are in the long term.  When the monetary volume inflation and rising debt eventually threaten the value of fiat currencies (the pound in especially vulnerable) large rises in interest rates are inevitable.  There will be a truly horrible recession at that point.  A lot of people will lose everything.  And the government will not be able to borrow very much to bail them out.  We could end up in a situation of both high interest rates and high energy prices.  That would mean stagflation.  Something that we are arguably experiencing already.

Last edited by Calliban (2021-04-15 08:56:17)


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#168 2021-04-15 09:32:05

louis
Member
From: UK
Registered: 2008-03-24
Posts: 6,921

Re: Settlement design

There are now quite a few examples of PV power coming in lower than 2 cents per KwH.

https://www.forbes.com/sites/dominicdud … 0fca0b4772

There are many things that could destroy our economy but PV power is not among them in my view.  The case for PV power is only going to get better with further technological innovations, improved recycling and price reductions.


Calliban wrote:

There are other market distortions that are muddying the water and give misleading impressions of what will be sustainable in the future.  For the past 12 years, interest rates have been less than zero when adjusted for inflation.  This effectively means that capital costs are zero.  That is the point of having low interest rates, it is supposed to stimulate investment and make investment more affordable.  But it also destroys effective returns on investment.  If pension funds are earning close to zero return, how big are those pensions going to be in 30 years time?  And it tends to result in rapidly inflating debt.  Why not borrow millions, if the effective interest rate is zero?  That is exactly what many zombie companies have done.  We are now in a situation where interest rates cannot rise without putting large parts of the economy into receivership.  The problem is, the longer they remain low, the more we are stealing from the future.

You may notice that the renewable energy boom didn't start until 2008?  First there was the spike in all energy prices due to the peaking of world conventional oil production.  Oil prices remained over $100/barrel until 2014.  You would expect that to stimulate interest in other sources of energy and it did.  Then interest rates dropped to zero and have remained there since.  Obviously, that makes highly capital intensive products like wind turbines very affordable, so long as interest rates don't rise above zero.  The question is, what happens when they finally have to?

So to summarise, nuclear build capability died in the UK in the early 90s.  It is now struggling to be reborn.  With North Sea oil and gas essentially gone, its success in doing so will determine whether we have a future as an industrial nation.  On the other side of things, zero interest rates are making wind and solar projects look a lot more affordable than they really are in the long term.  When the monetary volume inflation and rising debt eventually threaten the value of fiat currencies (the pound in especially vulnerable) large rises in interest rates are inevitable.  There will be a truly horrible recession at that point.  A lot of people will lose everything.  And the government will not be able to borrow very much to bail them out.  We could end up in a situation of both high interest rates and high energy prices.  That would mean stagflation.  Something that we are arguably experiencing already.


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#169 2021-04-15 09:45:33

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

Louis, traditionally, the cost of renewable energy projects was dominated by capital costs - about 90% of total lifetime cost.  Before 2008, when interest rates were something like 5%, that meant that 90% of the cost of a solar kWh was capital repayments and interest.  Then interest rates were reduced to zero, following the Great Recession, where they have remained ever since.  Now, a company can sit on that huge capital expense, pay practically nothing in interest and wait for inflation to reduce the value of the outstanding debt by 3% per year.  Under those conditions, I am not surprised that some solar arrays can generate at 2c/kWh.  My question is, what happens when interest rates return to normal?  Eventually, they will.  Are we going to be left with a lot of very expensive electricity generation and having to pay through the nose, or will the owners of that infrastructure go bankrupt, taking their bad debts with them?  I think we need to know.

When it comes to energy storage, everyone seems to think that with enough technology, someone will pull a rabbit out of a hat.  The problem it that we do already have energy storage technologies.  There is nothing to stop a utility building an electrolysis plant next to a CCGT and using renewable electricity to carry out electrolysis to produce hydrogen that would be stored in a tank and burned in the CCGT.  The problem is that 'storage' as you put it, really means building a whole other power station to generate power when the wind stops blowing.  It means more embodied energy and more cost and the process is inefficient.  The storage problem has already been solved.  It is just that no one likes the solution.  It isn't helpful.

Last edited by Calliban (2021-04-15 09:58:29)


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#170 2021-04-15 10:08:05

louis
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From: UK
Registered: 2008-03-24
Posts: 6,921

Re: Settlement design

Good luck with going to your bank and saying you've got this commercial project that needs loan funding and that you are prepared to pay 0%. A Virgin Start Up loan is currently at 6%.

Regarding methane power generation, the infrastructure is already there in the UK since we generate so much of our electric power from methane. So you would not have to build the plant.

Calliban wrote:

Louis, traditionally, the cost of renewable energy projects was dominated by capital costs - about 90% of total lifetime cost.  Before 2008, when interest rates were something like 5%, that meant that 90% of the cost of a solar kWh was capital repayments and interest.  Then interest rates were reduced to zero, following the Great Recession, where they have remained ever since.  Now, a company can sit on that huge capital expense, pay practically nothing in interest and wait for inflation to reduce the value of the outstanding debt by 3% per year.  Under those conditions, I am not surprised that some solar arrays can generate at 2c/kWh.  My question is, what happens when interest rates return to normal?  Eventually, they will.  Are we going to be left with a lot of very expensive electricity generation and having to pay through the nose, or will the owners of that infrastructure go bankrupt, taking their bad debts with them?  I think we need to know.

When it comes to energy storage, everyone seems to think that with enough technology, someone will pull a rabbit out of a hat.  The problem it that we do already have energy storage technologies.  There is nothing to stop a utility building an electrolysis plant next to a CCGT and using renewable electricity to carry out electrolysis to produce hydrogen that would be stored in a tank and burned in the CCGT.  The problem is that 'storage' as you put it, really means building a whole other power station to generate power when the wind stops blowing.  It means more embodied energy and more cost and the process is inefficient.  The storage problem has already been solved.  It is just that no one likes the solution.  It isn't helpful.


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#171 2021-04-15 10:50:41

kbd512
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Registered: 2015-01-02
Posts: 4,737

Re: Settlement design

In places where labor is nearly free, prices can be 2 cents per kWh.  The electricity prices per kWh, as paid by the rate payer, are NOT 2 cents in Germany.  They're at least triple what Americans pay.

No amount of government-sponsored market manipulation can change how much actual energy can be extracted from a kilo of Uranium or a liter of liquid hydrocarbon fuel or a square meter of solar panel erected in the sunniest locales on Earth for a given period of time.

The Chinese can and did (to weaken or eliminate overseas competition) sell steel below what it actually cost to produce their steel, in terms of raw energy input, but that doesn't mean such a practice is sustainable into perpetuity.  The Chinese will run out of money (energy) long before market demand is satisfied.  The moment they achieved their market share objective by cornering the market, they dramatically increased their prices to triple what they were before.  Of course it was all driven by greed, but they also had to increase prices in order to recoup their losses, in order to remain solvent.  After their stunt, other companies formed to domestically produce or recycle steel at lower prices using more efficient production processes, so that set a new market cap on how much the Chinese could charge for steel without driving their customers towards their new competitors.  The entire concept behind "economy" has always been devising the most efficient organization and employment of capital / labor / resources for delivering a good or service that paying customers actually want to buy.

In a market that isn't being manipulated by governments or corporations run amok, then prices (economization) will determine that if every other steel maker can produce steel for 2kWh/kg, but one particular company's production process is consuming 20kWh/kg, then that company or their current steel production process dies a natural death by being priced out of competition with all the other steel makers.  In that way, capital / labor / resources (one of them being energy) is conserved for other more productive uses.  That is how a normally functioning economy not being manipulated by governments works.  It also drives innovation to continually improve upon what was done previously, in order to deliver the same or substantially similar product for less energy and ultimately money.

If it takes 2 to 8 years for energy payback on a square meter of solar panels, here on Earth, then 18 to 12 years of energy output can be devoted to any other purpose.  If the energy production technology will be sustained into the future, then an additional 2 to 8 years of energy production payback will be devoted to producing new solar panels to sustain the output of solar power.  Mars receives half, 43% actually, as much solar radiation, so the panels used there either have to be twice as efficient or their energy payback time period doubles.

If it takes closer to 8 years than 2 years to achieve energy payback, but the panels degrade and produce less power over time, then we run into an ultimately unsolvable problem of energy payback duration being longer than the period of time that the solar panels can continue producing energy in a practical way.

The solar panel "game" is a very clever market manipulation that says, "Short term investment money is cheap right now, so we're going to take advantage of that fact by producing a product we know will be replaced in 20 years, and then 20 years from now when money is more expensive, the customer simply has to pay more money to continue receiving electricity."  There is, of course, a serious problem with that strategy.  It relies upon the availability of cheap investment money and government-sponsored market manipulation.  If the governments or the rate paying customers stop playing that game, then the jig is up, and suddenly energy becomes a lot more expensive and scarce.  We can see how well that strategy worked, longer-term, from the example of Germany, where electricity rates paid by their rate payers or 3 to 4 times higher than they are in the US.  People can always economize on energy usage, but only to a point.  After that point, it's just deprivation in service to ideology.  All of the money that could have been used for other useful purposes was and is tied up in producing enough energy to meet demand.  In France, there were / are riots over their government's market manipulations, and unrest is growing elsewhere as well.

Anyway, it takes very contorted ideologically-motivated thinking to refuse to acknowledge how a 100-to-1 energy payback is better than a 10-to-1 or 5-to-1 energy payback.  If wind and solar truly were producing abundant and cheap energy, then the prices for every other good or service using wind and solar energy should be falling, but they're not.  This is just the latest of an endless series of manipulative schemes to extract more and more money from a captive market that needs energy, little different than the market manipulations of OPEC or other special interests.

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#172 2021-04-15 11:45:33

Calliban
Member
From: Northern England, UK
Registered: 2019-08-18
Posts: 1,201

Re: Settlement design

As things stand, oil and gas reserves are still substantial, but they are rapidly depleting.  2018 was probably the all time peak year for oil production.  Reserves of natural gas are theoretically huge, if methane hydrate deposits can be tapped.  But so far, accessing this resource has proven difficult.  Easily accessible (conventional) gas production, peaked in the US at around the turn of the century.  UK production peaked around the same time.  Global coal reserves are huge.  We have barely scratched the surface of what exists.  There is an estimated 4 trillion tonnes of coal beneath the British sector of the North Sea alone.   Kerogen and tar sand deposits are similarly enormous.  Our problem is not lack of resources as such.  It is that the best resources, the high ERoEI resources, were exploited first.  What now remains is enormous quantities of low grade fossil fuels, that will be far more expensive to exploit and more environmentally damaging.  Our infrastructure grew to operate on high ERoEI fossil fuels.  As grade declines, oil and gas companies are being pushed into bankruptcy because there is a limit to what consumers can afford to pay.

We don't really have any safety net now to save us when the renewable energy bubble bursts.  We risk falling into the energy trap that Terraformer alluded to.


Interested in space science, engineering and technology.

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#173 2021-04-15 12:24:58

louis
Member
From: UK
Registered: 2008-03-24
Posts: 6,921

Re: Settlement design

Labour is not "nearly free" in Portugal and they had the lowest price quuoted. One of the US schemes was below 2 cents as well.

The v low prices are in locations which have some of the best insolation on the planet, so that makes sense. Germany has some reasonable resources in the Alpine region but nothing as good as the Middle East, Portugal or SW USA.



kbd512 wrote:

In places where labor is nearly free, prices can be 2 cents per kWh.  The electricity prices per kWh, as paid by the rate payer, are NOT 2 cents in Germany.  They're at least triple what Americans pay.

No amount of government-sponsored market manipulation can change how much actual energy can be extracted from a kilo of Uranium or a liter of liquid hydrocarbon fuel or a square meter of solar panel erected in the sunniest locales on Earth for a given period of time.

The Chinese can and did (to weaken or eliminate overseas competition) sell steel below what it actually cost to produce their steel, in terms of raw energy input, but that doesn't mean such a practice is sustainable into perpetuity.  The Chinese will run out of money (energy) long before market demand is satisfied.  The moment they achieved their market share objective by cornering the market, they dramatically increased their prices to triple what they were before.  Of course it was all driven by greed, but they also had to increase prices in order to recoup their losses, in order to remain solvent.  After their stunt, other companies formed to domestically produce or recycle steel at lower prices using more efficient production processes, so that set a new market cap on how much the Chinese could charge for steel without driving their customers towards their new competitors.  The entire concept behind "economy" has always been devising the most efficient organization and employment of capital / labor / resources for delivering a good or service that paying customers actually want to buy.

In a market that isn't being manipulated by governments or corporations run amok, then prices (economization) will determine that if every other steel maker can produce steel for 2kWh/kg, but one particular company's production process is consuming 20kWh/kg, then that company or their current steel production process dies a natural death by being priced out of competition with all the other steel makers.  In that way, capital / labor / resources (one of them being energy) is conserved for other more productive uses.  That is how a normally functioning economy not being manipulated by governments works.  It also drives innovation to continually improve upon what was done previously, in order to deliver the same or substantially similar product for less energy and ultimately money.

If it takes 2 to 8 years for energy payback on a square meter of solar panels, here on Earth, then 18 to 12 years of energy output can be devoted to any other purpose.  If the energy production technology will be sustained into the future, then an additional 2 to 8 years of energy production payback will be devoted to producing new solar panels to sustain the output of solar power.  Mars receives half, 43% actually, as much solar radiation, so the panels used there either have to be twice as efficient or their energy payback time period doubles.

If it takes closer to 8 years than 2 years to achieve energy payback, but the panels degrade and produce less power over time, then we run into an ultimately unsolvable problem of energy payback duration being longer than the period of time that the solar panels can continue producing energy in a practical way.

The solar panel "game" is a very clever market manipulation that says, "Short term investment money is cheap right now, so we're going to take advantage of that fact by producing a product we know will be replaced in 20 years, and then 20 years from now when money is more expensive, the customer simply has to pay more money to continue receiving electricity."  There is, of course, a serious problem with that strategy.  It relies upon the availability of cheap investment money and government-sponsored market manipulation.  If the governments or the rate paying customers stop playing that game, then the jig is up, and suddenly energy becomes a lot more expensive and scarce.  We can see how well that strategy worked, longer-term, from the example of Germany, where electricity rates paid by their rate payers or 3 to 4 times higher than they are in the US.  People can always economize on energy usage, but only to a point.  After that point, it's just deprivation in service to ideology.  All of the money that could have been used for other useful purposes was and is tied up in producing enough energy to meet demand.  In France, there were / are riots over their government's market manipulations, and unrest is growing elsewhere as well.

Anyway, it takes very contorted ideologically-motivated thinking to refuse to acknowledge how a 100-to-1 energy payback is better than a 10-to-1 or 5-to-1 energy payback.  If wind and solar truly were producing abundant and cheap energy, then the prices for every other good or service using wind and solar energy should be falling, but they're not.  This is just the latest of an endless series of manipulative schemes to extract more and more money from a captive market that needs energy, little different than the market manipulations of OPEC or other special interests.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#174 2021-04-15 12:55:15

RobertDyck
Moderator
From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 6,788
Website

Re: Settlement design

You guys go on and on. Here's a question: how are you going to smelt steel? I have proposed the Direct Reduced Iron Method. It uses less heat. Requires grinding ore to fines, uses carbon monoxide and hydrogen to convert oxide ores to pure iron. Carbon from carbon monoxide is dissolved into the iron. Using pure CO requires less energy, but results in far too much carbon in the steel. Metal with that much carbon is brittle. Removing the carbon requires heating the metal to completely melt it, and bubbling oxygen through to burn off carbon. If you mix hydrogen with CO for the first step, that hydrogen also binds with oxygen from the ore, converting ore to metal. Result is steam, which doesn't dissolve in steel. Hydrogen takes longer and requires more energy to make, but if you get the balance right then the final product won't have too much carbon. Although this works at lower temperature, it still requires between 800°C and 1,200°C; usually between 900°C and 1,000°C. This method requires high grade ore with very few impurities, basically pure iron oxide such as hematite concretions. Iron produced this way still has to be processed further to eliminate final impurities to become steel.

So how are you going to produce that much heat? Enough to heat literally tonnes of ore to well over +900°C? One advantage of this method is temperature is hot but low enough that a nuclear reactor can directly produce the heat without melting the reactor. Any conversion of heat from a reactor to electricity, then electricity back to heat, is very inefficient. It's far more efficient to directly use the heat. Temperatures for the Direct Reduced Iron Method is below the melting temperature of steel. You could use exotic materials for the reactor such as nickel/chrome allow to withstand higher temperature, but the point is to use the heat directly.

So again, if you want to go solar, how are you going to smelt steel?

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#175 2021-04-15 12:56:53

kbd512
Administrator
Registered: 2015-01-02
Posts: 4,737

Re: Settlement design

Louis,

It sounds like what you're saying is that it's much cheaper to generate energy in places with rich natural resources.  There is no place on Mars that is rich in sunlight, as compared to Earth.  As a result, the photovoltaics either have to become far more efficient or it's going to be far more expensive to use sunlight to produce energy, in terms of the energy cost of energy- because the energy to make energy has to come from somewhere.  I'm pretty sure that Calliban and I have made that exact point more than once.

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