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SpaceNut,
No significant number of people are ever going to live on Mars without nuclear reactors. The performance of available alternatives is too poor to be useful, in much the same way that wind turbines and photovoltaics here on Earth have solved zero energy problems. Many are net energy sinks because they're put in idiotic places not conducive to energy production, and we have no practical way to recycle them to the degree required to sustain this type of energy generating system into perpetuity.
Photovoltaics are generating energy 11% of the time here on Earth, on average. In places in California, such as Death Valley, photovoltaics produce energy 25% of the time. Wind turbines are generating energy 33% of the time here on Earth, on average, with coastal locations in Europe generating electricity 50% of the time. Very few places on Earth are as sunny as Death Valley or as windy as the North Sea. The amount and types of energy storage to make these energy systems with wildly varying output work at the scale required, is grossly impractical. The amount and types of metals to make them work, is only the first aspect of what makes them so impractical. Solar in Australia fluctuates by hundreds of GigaWatts.
The large offshore wind farm projects are being cancelled here in America because they are going to be as expensive or more expensive than a late and over-budget GigaWatt-class nuclear reactor.
If you recall, both Calliban and myself have proposed wind and solar energy projects that can actually work at the scale required. There were 3 key features of what I proposed:
1. Materials used were abundant, low-cost, and recyclable (steel, air, water, salt)
2. Proposed siting locations were prime real estate for such mega projects, with no attempt made to force round pegs into square holes, only to learn later that physics always wins
3. All of the solutions immediately converted collected solar energy into stored energy (compressed air, hot water or molten salt, or conversion into liquid hydrocarbon fuels using ocean-borne CO2), in order to make that energy dispatchable, which was also factored into the cost of the proposed projects and material consumption estimates
Since my proposals start with 3X more energy from solar by foregoing a conversion to electricity, and include no specialty metals, we can afford to eat some waste and inefficiency, because it's already factored into the solution, and there is no "next great problem to solve" as a result. We are achieving a much better bang-for-buck ratio, because the system lasts 3X longer. The ratio, relative to photovoltaics and wind turbines, is 9X greater to start with, so even if it's only 50% overall efficient at using the stored energy (primarily compressed air and hot water), then we still get 4.5X more energy out. As I showed, however, we can cover something like 63X more surface area with stamped sheet steel for the same energy input required to make a photovoltaic panel, per square meter. Energy cost is direct and unavoidable, "can't be papered over with money", cost, even though it also has monetary implications for our system of trade. This is important, because area covered is the name of the game for wind and solar, because sunlight is very weak energy per unit area, which is why you don't burst into flames when you walk outside. Wind energy is weaker still, only about 3% of the total solar energy we receive. This means you need to cover massive areas with very low cost materials that are 100% recyclable.
I did this work because I was alarmed at how unworkable the presently proposed solutions are, not because I was enamored with my own ideas. I don't even like my ideas about energy. It's more like an act of desperation to arrive at a workable sustainable solution near-term (20 years) solution that doesn't require completely turning the existing civilization inside-out, only to discover that some major part of the plan is unworkable, which is what photovoltaics and wind turbines and batteries require. What I learned along the way is that there are no silver bullets, and that includes nuclear energy. The only reason to go gangbusters on nuclear energy is the simple fact that the supply of hydrocarbon fuels is contracting from lack of drilling and the presently proposed solutions utterly ignore physical reality. There are only a never-ending series of huge costs, significant trade-offs, and major concessions to overall usability, in comparison to hydrocarbon fuels.
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If you recall, both Calliban and myself have proposed wind and solar energy projects that can actually work at the scale required. There were 3 key features of what I proposed:
1. Materials used were abundant, low-cost, and recyclable (steel, air, water, salt)
2. Proposed siting locations were prime real estate for such mega projects, with no attempt made to force round pegs into square holes, only to learn later that physics always wins
3. All of the solutions immediately converted collected solar energy into stored energy (compressed air, hot water or molten salt, or conversion into liquid hydrocarbon fuels using ocean-borne CO2), in order to make that energy dispatchable, which was also factored into the cost of the proposed projects and material consumption estimates
I remember with concentrated solar thermal but that is a long ways off with mars start up as it requires lots of equipment to mine and process with nothing yet for the building tools that will be required to do this mega sized project as cargo only with no people to setup or get the equipment functioning.
We know that just co2 intake and separation requires temperatures near 800 c in the chambers in the unit for MOXIE to produce the needed ingredients for co + o2 use to even get a start with 300w for using solid oxide electrolysis yielding 98% purity at a rate of 6–10 grams per hour (0.21–0.35 oz/h).
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A fourth factor that is also applicable, is to use power when it is available without attempting storage and power down when power output is lower. This is tricky in practice, but it avoids all of the energy losses and equipment costs associated with energy storage. It is how renewable energy was used in practice before we discovered coal. And it is how we continue to use it today. To use an analogy: When the sun goes down, we don't bring out artificial lights to keep our crops growing. We just accept the fact that they will grow well on sunny days and less well on overcast days. Some harvests achieve lower yields, which is why we have food storage. We make hay whilst the sun shines.
This the only practical way that renewable energy can work in my opinion. Energy storage is a weak solution however it is done. And given that EROI for these energy sources is weak anyway, energy losses need to be minimised. Working with the weather will be an inconvenient way of living for most people. And it makes lean JIT manufacturing quite impossible. At the home level, power would be available some days and on other days it will not. People will need to adapt to this as there is no way of avoiding it if we live on intermittent energy. Storage just isn't practical.
Whether it is possible to maintain an industrial system under this arrangement, I don't know. I am quite sure that people will hate it. When the wind is strong, people will be working 18 hour back to back shifts to make use of energy whilst it is available. When it is not, they will have time off without pay, whether they want it or not. And their time off will probably coincide with having no electricity. They will be on call and required to respond at short notice. And whether they are working their nuts off or idling on a particular day, is entirely down to the changing moods of nature.
How long will people live like this before getting tired and pissed off? I think the answer to that question is: Not very long! After a year of living like this they will be begging 'the government' to start building nuclear reactors. People that slow down and get in the way of that process will not be treated with any patience. Right now those people are humoured, because no one alive now has had to experience the reality of living on intermittent energy. The reality is that living on intermittent energy means an intermittent life. People will enjoy that about as much as going to the dentist.
Last edited by Calliban (2023-11-17 06:58:07)
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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Calliban,
Agreed. Beyond the existing pumped hydro systems, which can't be dramatically expanded for a reasonable amount of money, long term energy storage is grossly impractical at the scale required. Economic and material resource scarcity reality is starting to reassert itself. Nuclear reactors or liquid hydrocarbon fuels are absolutely necessary to supply base load power. Apart from burning more coal and natural gas, only nuclear reactors are a practical alternative option, which ideologically neutral people have known for quite some time. Waste heat from the reactor fleet can either add to the hot water supply, or reactors can pull double duty by desalinating sea water. Mechanical power, along with hot and cold potable water, are foundational to human society. Electricity is also important in modern times, but only when the output is both clean and stable. The output of so-called "renewable energy" or "green energy" electric generation is not clean (constant 60Hz frequency, perfectly sinusoidal AC power), nor is it stable (multi-hundred GigaWatt power fluctuations for large installations in places like Germany or Australia, which must be internally balanced, else not 1 kilo of coal or cubic meter of natural gas can be shut off at any time).
Electricity is only superficially cheap, and only feasible when it's clean sinusoidal power with near-100% availability, because periods of non-availability are synonymous with a power grid crash, wherein very large / expensive / time consuming to replace pieces of electrical machinery are damaged by brown-outs or black-outs. If the pressure in a compressed air service line varied by +/10%, nobody would even notice. That's a feature of a durable and resilient mechanical system. The very instant available electrical power generation dips 10% below demand, a grid crash is a foregone conclusion.
Apart from computing and certain types of computerized control systems, all electrical and especially all electronic systems are very fragile and failure-prone. An electrical, or now electronic, motorized car door window has dozens of failure modes. So long as your arm still works, your manual mechanical roll-up window still works. It simply cannot fail or cease to work entirely, merely because the car's engine or battery or computer or motor or switch or wiring, ceases to function as intended. If the gear teeth are made from steel and greased during installation, then it will probably never fail until it is physically destroyed. At that point, any electrical or electronic system would be equally destroyed, merely much more expensive and difficult to repair or replace.
Electricity is also incredibly wasteful, because it's an artifact of overall energy-intensive and wasteful industrial processes. All the machinery and industrial processes required to produce electricity (power input, electric generator if the power input is not from photovoltaics, step-up transformers, step-down transformers, power lines, more transformers to convert the electricity to DC power for electronics, more specialty metals and energy-intensive processes to make electronics), is what makes it wasteful. In general, electrical machines are very efficient individually, but not efficient enough to overcome the process and power distribution inefficiencies. If we consider that half of all mining energy input and tailing waste generation is associated with Copper mining alone, it's not cheap or efficient at all. On top of that, we would require Lithium or Sodium and a slew of other specialty metals, in addition to absurdly consumptive semi-conductor production. All are artifacts of other mining processes that co-produce specialty metal ores in conjunction with, for example, Zinc production. If you want rare Earth metals, then you need to mine those more common metals, thus production of the more common metal ores becomes the limiting factor in production of specialty metals. Well, if we mine 10X more Zinc, then it requires 10X more energy input, yet we still need 100X to 1,000X more of the specialty metal that we're actually going after. At some point, too much energy is being devoted to mining instead of all the other uses for energy. Hydrocarbon fuels gave us a temporary "free ride" to devote enormous energy input to what would otherwise be a losing proposition.
Very short term energy storage for powering vehicles is practical when you can get more of the energy out by not suffering the conversion penalties associated with generating electricity, or by not squandering waste heat generated by air compression. The requisite supply of air and hot water doesn't amount to an insurmountable increase in generating or storage capacity, because it doesn't immediately run afoul of specialty metal acquisition from mining. A compressed air / hot water transportation solution is a "flow-through" system, with greater total capacity than a liquid hydrocarbon fuel based system, in which the consumed products are constantly being pushed through the trompes (gravity machines with no moving parts, as you pointed out, and gravity is pretty reliable inside a deep gravity well), service pipeline networks, gas stations, and the commuter vehicle fleet or household appliances. CO2 is the most abundant / non-toxic / readily available refrigerant for refrigerators, air fryer ovens, air conditioners, and onsite electrical generators, which will only need to power LED lights and personal computing devices.
Future homes and cities will require hot and cold water pipes, as well as compressed air pipes. There won't need to be grid-connected electrical systems or natural gas pipelines, drastically reducing the demand for Copper and other energy-intensive specialty metals with strictly limited supplies. Since most consumer electronics are now battery operated, and LED bulbs with small batteries can run for days on a single charge, there won't need to be much in the way of onsite electrical wiring, either. This is an appropriate use for Lithium-ion batteries that won't run into supply constraints. If there is any wiring in new build residential structures, it will consist of small low-voltage DC power cables of the sort used to recharge cell phones. Assuming no external or internal high-voltage / high-amperage electrical wiring, and no natural gas, because short range vehicles use compressed air and hot water, there's very few remaining ignition sources for fires. Home power tools can use compressed air instead of electricity and batteries or gasoline. Someone with hand tools and lubricants can maintain their air powered home workshop and yard tools for the better part of a lifetime.
The first order of business when building a new home will be getting compressed air service lines operating so construction tools can take advantage of onsite compressed air. If there's not enough air, water, and steel to make this new low energy density generating and storage scheme work for light transport and light construction work, then there will certainly never be enough specialty metal to make the electrical equivalent of a Rube Goldberg machine function at the same scale. Over the past 50 years, we've created what was ultimately pointless additional complexity, to attempt to arrive at long term sustainable solutions, only to discover that the additional complexity was a major factor affecting the general practicality of the proposed electrical / electronic solutions at the scale required.
There are 2 to 3 trips I make per year that require a combustion engine, and might otherwise be impractical using compressed air. If the vehicle has a range of 100 miles at 55mph, then perhaps even those trips are practical to do with compressed air. The rest of the time, all of my driving is within 25 miles. Spending 5 minutes to fill up on the other end is not a major problem. I can't easily travel 10 to 25 miles per day without a car, but what powers it is optional. It's rare for my vehicle to achieve 40mph, and almost all driving is under 55mph. The speeds achieved are an artifact of living in a large city with lots of other motorists. Large concentrations of people and vehicles dramatically reduce driving speeds, resulting in lots of start-and-stop driving. I suspect that also describes the overwhelming majority of real world day-to-day driving for your average commuter. I don't think using compressed air vs gasoline would dramatically affect the utility of a car inside a city, and air quality would improve dramatically. The hard requirement there is to make the vehicle and its alternative energy supply cheap, pervasive, easy to use, and easy to maintain. We already maintain compressed natural gas pipelines, so I can't see compressed air being inordinately more difficult, and compressed air is not explosive or particularly harmful to the environment if there is a leak.
We can have 600psi compressed air and hot water service pipelines that draw in air from either the Great Lakes or from the Atlantic and Pacific. We will protect the trompes and pipes with a Silicon-based CVD coating to inhibit corrosion. The pipes will probably live longer than their first cohort of users / beneficiaries. At service stations, the 600psi air can be compressed to 4,410psi / 300 bar. The high pressure parts of the system will likely require recycling roughly every 10 years or so, as pressure cycles take their toll on the steel storage tanks, which are essentially high pressure SCUBA diving tanks presently used at that pressure level to store air for diving activities.
The biggest questions I have are:
1. Will people accept this new way of powering their commuter cars and home appliances, or will they see it as too great an imposition?
2. Can we make the required machinery cheap enough to implement at a global scale?
3. Do we have enough remaining coal and natural gas to do this if we start in the near future?
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Further discussion on compressed air, etc, moved to the thread below, to avoid contaminating the CO for Mars thread.
https://newmars.com/forums/viewtopic.php?id=10448&p=9
"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."
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The compressed mars air can also be used here Running on Compressed Air?
Also in storage of energy as well.
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