The primary feedback mechanism I can think of that would prevent this is widespread civil unrest. Of course, if the military and police robots are good enough, that might be short circuited. Otherwise, the fallout from the civil unrest would probably be for us to end up with some other worst-case scenario. Probably pointless make-work for people to earn a pittance at. Have you met people? Most people's strongly held beliefs about what's in their best interests are crazy.
Frankly, with the kind of scripts Hollywood has been churning out lately, the AI might not need to be all that strong. We just need to develop an engine that can parse some Austen or Shakespeare, maybe throw in _Cyrano de Bergerac_, change the setting and characters a bit (setting and characters working in marketing, magazines or TV production seem to be really popular) and voila, a good 50% of scripts right there. For that matter, the backlog of perfectly good scripts (relative to what actually gets produced) floating around Hollywood could last for a good hundred thousand years or so.
You can be entertained by two dancing girls instead of one, or ten, or twenty. The best part is, if you happen to have come out on top and own the robots doing the producing, that if you have twenty dancing girls instead of one, they each know that they're easily replaceable and will work for less and put up with a lot more.
The thing about the Luddites is that the problem they saw was not an imaginary one. A fair number of textile workers really did starve to death from losing their jobs. Just because the market corrects itself over time does not mean there isn't a human cost in life and suffering. Social reforms such as unemployment insurance and welfare were what was needed, not destroying the machines, but if people just quietly died in ditches, we probably wouldn't have gotten the social reforms. The same thing continues to be true today.
Most entertainment jobs, as an example, and that segment of the market keeps growing.
The reason that's a problem is that, unless you embrace a post-scarcity philosophy where people are granted some sort of living wage as a human right, having ninety percent of the human population working to entertain one another doesn't work. They all have to compete to entertain the remaining 10% and the profits from that need to be spread out among the remaining 90%. It's the problem of supply and demand. There's going to be a limit on demand. As for human desires being practically infinite, that's not really true, but some of them are quite large. Of course, what that means is that 90% of the population has to work as cheap sex workers for the remaining 10%. Not exactly ideal
It would be upwards relative to my personal notion of up. Anyway, I said "microgravity" not zero gravity. For the sake of argument, my feet are strapped to a small asteroid, with 1/1000th the surface gravity of Earth. Or, I'm on a space station, but I'm at one of the far ends, with 90% of the mass of the space station in the direction of my feet. Or there's a slight spin to the space station. Or who cares. The point is that the statement "In space (you probably meant "in orbit") you have to be exactly as strong as on Earth to lift things" isn't correct. Even if your objection holds, it still doesn't make it correct, because that poster said "lift" as well.
How do you compare a sterling engine to a car engine?
Only on a limited set of parameters and in the context of a larger system. For example, if you had two otherwise identical cars, one with a "sterling[sic]" engine powered by a small gasoline furnace and one with an internal combustion engine, you could compare the two cars on details such as miles per gallon, max RPMs, engine torque, engine responsiveness, etc. Generally speaking, the comparison between gasoline engines and Stirling engines in the context of cars just doesn't work because Stirling engines aren't really suitable for that application for a number of reasons, such as responsiveness. You clearly already know this. Stirling engines would be much more suitable for systems that buffer the power from the Stirling engine somehow, such as in hybrid cars with all-electric drive systems but with a combustion engine purely for generating electricity. In a system like that, you could make a more direct comparison between the internal combustion engine and a Stirling engine doing the same job.
Of course, I'm not sure why you brought up Stirling engines. I certainly didn't mention them in my post. In my post, I was responding to your post:
30% or fuck off. Also solar panels are not durable over time and are expensive to make and replace.
Where _you_ were also comparing apples and oranges. The "efficiency" of an internal combustion engine is clearly not the same thing as the "efficiency" of a solar cell. To directly compare them, an "efficiency" number would have to be adjusted based on all kinds of facts about the broader system they're a part of, otherwise it's meaningless.
You felt the need to talk about the durability of solar cells in a discussion about solar power vs. combustion engines in the context of powering cars, so I responded. Solar cells cost money to produce and have limited lifetimes. Car engines cost money to produce and fuel and have limited lifetimes. Over an optimistically long life, a car engine optimistically uses up about 39X its initial cost in fuel. Basically, the car engine can't hold a torch to the solar cells in terms of lifetime cost for the power it outputs (ignoring that one is outputting mechanical power and the other electrical). On the other hand, unless we move a lot closer to the sun, solar panels can never compete on power density to internal combustion engines in a car application because of the limited surface area. Still, internal combustion engines can't really compete with electric motors in nearly every way that makes them useful in a car which would make stationary power generation (possibly though solar cells) and electric cars a wonderful idea if it weren't for the electrical storage problem.
The soot clearly wouldn't provide protection for long, I certainly concede that. Just how completely the ozone layer would be depleted isn't really clear, however. Even in a worst case scenario, loss of the ozone layer doesn't mean all UV light gets through. The UVC gets blocked by the rest of the atmosphere regardless, the major rise would be in UVB. The direct effects would be very bad for the short term and long term health of non-nocturnal land animals incapable of finding shelter. The nocturnal ones or the diurnal ones which modify their behaviour and only expose themselves in the mornings or evening could probably get by. The more pressing concern is plant life on land which would provide much of the necessary shelter for non-burrowing animals and also makes up a good chunk of their food supply. To start with, many plants already have vastly better UV resistance than animals. They're more resistant to DNA damage and have various protective mechanisms. Are there plants that could survive at the equator in high summer with no ozone layer whatsoever? Hard to say absolutely since there are so many potential survival strategies, but most of the existing trees, for example, would probably die off along with their leaves. Grasses that grow thick and deep might be able to survive with dead upper layers protecting living layers underneath. In higher latitudes, the UV wouldn't be a problem all year round and trees could probably survive. In summer, leaves would probably tend to die off, but they could probably still eke out an existence as long as they have fairly opaque bark. All the vegetation that would die off would make way for other life, such as fungi which could take their place in the food chain.
Don't misunderstand me, it would be a massive, massive disaster and extinction event. Still, it's not inconceivable for many living things, including many types of large land animal, to survive through the disaster and repopulate afterwards.
The thing about that though is the question of what economic activity arises for people to participate in for employment. We're already living in an age where most of the useful labour is done by a relatively small percentage of the population. Most of the rest works in various types of service job. Robots like this can replace human workers in entire large segments of those service industries. Sure there are other service jobs, but there are a lot of them that really are of the replaceable with a simple shell script variety. With a little more machine intelligence, the majority of them probably are replaceable that way. Eventually, there won't be any low or no-skill jobs left. Even the jobs fixing the machines will be done by machines. The simple fact is that most people aren't high-skilled labour and even those who are highly skilled or are very, very good at their jobs often can't compete with a custom designed machine (shades of John Henry). The truth is that the new economy jobs that gradually replace the old ones are worse and worse and the typical labourer is going to have to sell their labour on what is increasingly a buyers market.
The problem is that farming, mining, manufacturing, food service, retail sales, warehouse jobs, delivery, construction, etc. can all conceivably be replaced almost entirely by machines. The owners of the machines, farms, mines, factories, restaurants, stores, warehouses, delivery companies, construction companies, etc. will then be the only people producing the tangible things that the consumers truly need, while the majority of the consumers will be working in service jobs producing intangibles that people don't really need.
In other words, we are in danger of transitioning to post-scarcity technology without transitioning to a post-scarcity economy. That leaves most people, at best, working themselves to death in completely unproductive, pointless jobs.
I'm fairly certain that, in microgravity, with my feet strapped down, I could take a 5000 kilogram dumbell sitting at my feet with my hands and lift it up over my head. I couldn't do it very quickly, due to inertia, and I would have to start working against my initial movements at about the halfway mark to stop it from yanking itself out of my hands (or yanking off my hands) at full extension.
not 4.696 gigawatts!
4.696 Megawatt! ~ 5 Gigawatt off by a factor of 1000
I'm assuming you were educated somewhere where the comma (,) and the period (.) have opposite usage in mathematical notation to the way I use them. It's an unfortunate problem with mathematical conventions. To be clear, when I wrote "4.696 gigawatts" I did not mean: "four thousand six hundred and ninety six gigawatts", but rather "four gigawatts plus six tenths of a gigawatt plus 9 hundredths of a gigawatt plus 6 thousands of a gigawatt". If I had intended to express any number of thousands of gigawatts, I would typically have jumped up to terawatts. If I'd only thought to round up to avoid three significant digits after the decimal point or if I'd written "1,134 square kilometers" instead of just "1134 square kilometers", this could have been avoided as it would have been more obvious from context that I wasn't using the period as a thousands delimiter. On the other hand, other context, such as the way I wrote "113.4 gigawatts" or the way I spelled "kilometer" or just the fact that I'm writing in English on a US-centric website was available.
That is correct, and is what I was trying to say. The professor quoted by the original poster was obviously wrong since the evacuation area covered in solar cells would produce approximately 20 times the power of the plant itself (actually only about 10 because I forgot that about half of it is water).
I'm wondering if misunderstanding of my units was why I was actually modded down as "overrated" when the original hearsay post which didn't list any of the facts or math used to reach its conclusions, was modded to +5 informative. But that seems unlikely on Slashdot. Most readers here wouldn't have misread the units the way you did.
In any case, the other point from the original post I didn't address was cost. pi*19000^2 is 1134113990. That's the number of square meters in the evacuation zone, but we'll halve it because of the water to 567056995 square meters. We can just call it 570 million square meters. Covering that with solar cells would surely be expensive. The problem is, the unnamed professor in the original post has set an interesting challenge by saying that covering the evacuation area with solar cells would both produce less power and cost more than the nuclear plant. The problem is that, since the first claim is false by an order of magnitude, do we have to disprove the second claim only for a tenth of the area, or do we have to hand victory to our invisible opponent on half of his claim even though the second claim clearly should only be considered in conjunction with the first?
I'll have to start by saying that I couldn't find numbers for the construction of operating costs for the plant, although there was lots of information about the cleanup costs. New nuclear construction seems to about $5000 per kilowatt though, so we can maybe estimate $25 billion ($25X10^9). Hard to say if that's accurate or not, but it looks like it's certainly going to end up costing more than that in the end. So, if we divide $25 billion by the 570 million square meters for the solar cells, we get about $43 per square meter. It is hard to beat that with solar cells. The best price I could find in a five minute search was $49 and 32 cents per square meter just for the cells and obviously there would be more infrastructure required. Of course, since that's for 10X the production of the nuclear plant, it seem more fair to compare say that you have $430 to spend per square meter, which is much, much more reasonable.
Why would you think soot could replace ozone as a UV blocker?
Because carbon-carbon bonds absorb UV light. It would be temporary compared to the overall length of the UV depletion, of course. The chief survival mechanism would still be sheltering from the light. Things living in high latitudes would have a much easier time. Don't get me wrong, it would be devastating to life in general and there would be mass extinctions and very tough living conditions. But the world wouldn't be sterilized. There are events that could certainly sterilize the world, but the one under discussion, which only has secondary effects on the other hemisphere, wouldn't be enough.
Half the world on fire is still only half the world on fire. This planet is broken up into land masses separated by ocean. There would be a lot of soot and byproducts causing terrible air quality, and probably some "nuclear winter" style weather for a while. Lots and lots of things would die, but certainly not everything. As for the loss of the ozone layer, the soot would probably make up for that. The ozone layer would recover and animals would modify their behaviour to avoid excessive sun damage in the meantime.
The concentrations would have to be startlingly high to actually wipe out all surface life. Even then, the life that doesn't breathe, or lives in the ocean, or just isn't as badly affected as large mammals would be just fine.
The life expectancy of a solar panel tends to be better than the life expectancy of a car. Cars and their engines also tend to be expensive to make and replace. A new engine for my sisters car would cost $3,745.00 and is 113 kg. And can produce something like 180 kilowatts optimistically. Of course, it would burn out fast actually producing at that rate. The operational life, actually running, tends to optimistically be about 7 months for a car engine in a car. So, a kilogram of car engine could be said to produce 1.6 kilowatts per kilogram at a cost of $20.80 and lasts 7 months and would consume about A kilogram of thin film solar cell (not counting the glass panels), have demonstrated power levels above 1 kilowatt per kilogram and would almost certainly last for 20 years, which would mean at least 21.4 times the power production of the car. Of course, at the moment, I can't say for sure that the solar panels would cost less than the $445.00 to make it even in lifetime power production with the car engine. Of course, the solar cells wouldn't need the approximately 270 gallons of gasoline the kilogram of engine would use in that time, adding another $810.00 (at an optimistic $3.00 per gallon) to the cost of the car engine power.
Overall it's clear that it's really hard to directly compare these things. Achieving the power density of a car engine with solar cells placed on a car is clearly impossible on this planet. Achieving the abundance of solar power with any fossil fuel is also a clear impossibility since fossil fuels are just solar power stored with miserable efficiency. Personally, I have high hopes at the moment for air-breathing batteries with similar energy density to fuels like gasoline (at least 50% of the density would be all that would be needed), but they also need to have sufficient recharge cycles and low enough cost so that periodic battery replacement plus cost of recharge power doesn't exceed the cost of gasoline. The recharge cycles problem is a technical problem that probably can be solved. Ditto for the cost of recharge power. The cost of replacement batteries, however, is at the mercy of car manufacturers, salivating at the prospect of collecting monopoly rents from captive customers. Pity.
What were the numbers on that? The number I can find for the evacuation area is a 19 km radius, which is 1134 square kilometers. Covered in solar cells, assuming about 100 watts per square meter (10% efficiency with 1 kw/square meter insolation), that should produce 113.4 gigawatts. From what I can find, Fukushima Daiichi had a maximum capacity of 7.456 gigawatts with a typical production of 4.696 gigawatts. The power plant site itself was 3,480,299 square meters. So, just the power plant grounds covered in solar cells could have produced 348 megawatts, which would be about 7.4% of its capacity.
Beyond those numbers, I wonder what the real footprint of the plant was. We should ignore initial construction, but we can't ignore that the power plant ran on fuel that required mining and processing. Perhaps all processing was done on site, but the mining and basic refining couldn't have been. How much area was devoted to acquiring the nuclear fuel for the plant? Uranium mining tends to eat some pretty hefty chunks of land. I did a search for info on how much land it actually takes up, but can't find a source that has already compiled a number. It does seem possible that it could use up even more land than the power plants themselves. If it manages to make it to 14:1 for Fukushima Daiichi, that would mean that the land area devoted to generating the nuclear power could be covered in solar cells instead to produce the same power. It's obviously a bit more complicated than that, but it's still very interesting.
Ok, let's do the math. Total electrical consumption (not all energy usage, just electrical) for the US is about 480 gigawatts. Average insolation is about 1 kw per square meter. At 10% efficiency, that means about 100 watts for every square meter of panel. That means you need 4.8 billion square meters of panels. 4.8 billion square meters can fit into a square 69.282 kilometers on a side. That's somewhere between the size of Rhode Island and Delaware.
Even if you expand that to all energy usage, not just electrical, you're talking approximately 3 terrawatts. So, that's about 30 billion square meters of panels. That's a square about 173.2 kilometers on a side. That's somewhere between the size of Maryland and Hawaii.
So, if you actually sit down and DO the math, you can easily cover US electrical requirements and, in fact the total US energy usage (not counting food energy and not considering the fact that much of that energy usage can't currently be converted to electrical) without coming remotely close to covering the US with solar panels.
Of course, if you'd actually done the math on your own claims, you would have realized that, when you claimed that you could "optimistically" supply 7.5% of the US's electrical supply with 0.01% of the surface area, that would mean that you could "optimistically" supply 100% of the electrical supply with 0.133334% of the surface area, or even pessimistically (let's pretend that the difference between "optimistic" and pessimistic is an order of magnitude) with 1.33334% of the surface area.
So, it's pretty clear that you either didn't do the math yourself, or you just decide to bluff. If you meant something else, like that there are logistical problems in covering that much area, then say so.
Conversely, there are others willing to use violence only because of pacifism. Without the majority being peace-loving, we would all be dead from the constant fighting and killing. Obviously pacifism can be taken to the extreme, such as those who refuse to even kill plants and therefore fast themselves to death.
Either way, the term "planetary distances" that was used is clearly not accurate, whether it's two orders of magnitude too small or two orders of magnitude too big.
I'm curious. If the grants that pay for your salary and equipment are public money, as you seem to imply, what do you think entitles _you_ to that money? Is there meant to be a quid pro quo, and, if the money is public, who is meant to be the beneficiary?
Generally speaking, it takes them a very, very, very long time to do anything about ponzi schemes. Bernie Madoff ran his ponzi scheme for at least 15 years (by his admission) and probably actually for something like 30 years before anything was done about it.
So, the moon, which is 409,073 kilometers away at its furthest is "planetary distances"? What does that make the distance to Venus, which is 41 million kilometers at its closest or Mars, which is 56 million kilometers at its closest. Seems to me that this is only over about 1% of the shortest distance you could actually consider "planetary distances".
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The primary feedback mechanism I can think of that would prevent this is widespread civil unrest. Of course, if the military and police robots are good enough, that might be short circuited. Otherwise, the fallout from the civil unrest would probably be for us to end up with some other worst-case scenario. Probably pointless make-work for people to earn a pittance at. Have you met people? Most people's strongly held beliefs about what's in their best interests are crazy.
Frankly, with the kind of scripts Hollywood has been churning out lately, the AI might not need to be all that strong. We just need to develop an engine that can parse some Austen or Shakespeare, maybe throw in _Cyrano de Bergerac_, change the setting and characters a bit (setting and characters working in marketing, magazines or TV production seem to be really popular) and voila, a good 50% of scripts right there. For that matter, the backlog of perfectly good scripts (relative to what actually gets produced) floating around Hollywood could last for a good hundred thousand years or so.
You can be entertained by two dancing girls instead of one, or ten, or twenty. The best part is, if you happen to have come out on top and own the robots doing the producing, that if you have twenty dancing girls instead of one, they each know that they're easily replaceable and will work for less and put up with a lot more.
The thing about the Luddites is that the problem they saw was not an imaginary one. A fair number of textile workers really did starve to death from losing their jobs. Just because the market corrects itself over time does not mean there isn't a human cost in life and suffering. Social reforms such as unemployment insurance and welfare were what was needed, not destroying the machines, but if people just quietly died in ditches, we probably wouldn't have gotten the social reforms. The same thing continues to be true today.
Most entertainment jobs, as an example, and that segment of the market keeps growing.
The reason that's a problem is that, unless you embrace a post-scarcity philosophy where people are granted some sort of living wage as a human right, having ninety percent of the human population working to entertain one another doesn't work. They all have to compete to entertain the remaining 10% and the profits from that need to be spread out among the remaining 90%. It's the problem of supply and demand. There's going to be a limit on demand. As for human desires being practically infinite, that's not really true, but some of them are quite large. Of course, what that means is that 90% of the population has to work as cheap sex workers for the remaining 10%. Not exactly ideal
It would be upwards relative to my personal notion of up. Anyway, I said "microgravity" not zero gravity. For the sake of argument, my feet are strapped to a small asteroid, with 1/1000th the surface gravity of Earth. Or, I'm on a space station, but I'm at one of the far ends, with 90% of the mass of the space station in the direction of my feet. Or there's a slight spin to the space station. Or who cares. The point is that the statement "In space (you probably meant "in orbit") you have to be exactly as strong as on Earth to lift things" isn't correct. Even if your objection holds, it still doesn't make it correct, because that poster said "lift" as well.
How do you compare a sterling engine to a car engine?
Only on a limited set of parameters and in the context of a larger system. For example, if you had two otherwise identical cars, one with a "sterling[sic]" engine powered by a small gasoline furnace and one with an internal combustion engine, you could compare the two cars on details such as miles per gallon, max RPMs, engine torque, engine responsiveness, etc. Generally speaking, the comparison between gasoline engines and Stirling engines in the context of cars just doesn't work because Stirling engines aren't really suitable for that application for a number of reasons, such as responsiveness. You clearly already know this. Stirling engines would be much more suitable for systems that buffer the power from the Stirling engine somehow, such as in hybrid cars with all-electric drive systems but with a combustion engine purely for generating electricity. In a system like that, you could make a more direct comparison between the internal combustion engine and a Stirling engine doing the same job.
Of course, I'm not sure why you brought up Stirling engines. I certainly didn't mention them in my post. In my post, I was responding to your post:
30% or fuck off. Also solar panels are not durable over time and are expensive to make and replace.
Where _you_ were also comparing apples and oranges. The "efficiency" of an internal combustion engine is clearly not the same thing as the "efficiency" of a solar cell. To directly compare them, an "efficiency" number would have to be adjusted based on all kinds of facts about the broader system they're a part of, otherwise it's meaningless.
You felt the need to talk about the durability of solar cells in a discussion about solar power vs. combustion engines in the context of powering cars, so I responded. Solar cells cost money to produce and have limited lifetimes. Car engines cost money to produce and fuel and have limited lifetimes. Over an optimistically long life, a car engine optimistically uses up about 39X its initial cost in fuel. Basically, the car engine can't hold a torch to the solar cells in terms of lifetime cost for the power it outputs (ignoring that one is outputting mechanical power and the other electrical). On the other hand, unless we move a lot closer to the sun, solar panels can never compete on power density to internal combustion engines in a car application because of the limited surface area. Still, internal combustion engines can't really compete with electric motors in nearly every way that makes them useful in a car which would make stationary power generation (possibly though solar cells) and electric cars a wonderful idea if it weren't for the electrical storage problem.
The soot clearly wouldn't provide protection for long, I certainly concede that. Just how completely the ozone layer would be depleted isn't really clear, however. Even in a worst case scenario, loss of the ozone layer doesn't mean all UV light gets through. The UVC gets blocked by the rest of the atmosphere regardless, the major rise would be in UVB. The direct effects would be very bad for the short term and long term health of non-nocturnal land animals incapable of finding shelter. The nocturnal ones or the diurnal ones which modify their behaviour and only expose themselves in the mornings or evening could probably get by. The more pressing concern is plant life on land which would provide much of the necessary shelter for non-burrowing animals and also makes up a good chunk of their food supply. To start with, many plants already have vastly better UV resistance than animals. They're more resistant to DNA damage and have various protective mechanisms. Are there plants that could survive at the equator in high summer with no ozone layer whatsoever? Hard to say absolutely since there are so many potential survival strategies, but most of the existing trees, for example, would probably die off along with their leaves. Grasses that grow thick and deep might be able to survive with dead upper layers protecting living layers underneath. In higher latitudes, the UV wouldn't be a problem all year round and trees could probably survive. In summer, leaves would probably tend to die off, but they could probably still eke out an existence as long as they have fairly opaque bark. All the vegetation that would die off would make way for other life, such as fungi which could take their place in the food chain.
Don't misunderstand me, it would be a massive, massive disaster and extinction event. Still, it's not inconceivable for many living things, including many types of large land animal, to survive through the disaster and repopulate afterwards.
The thing about that though is the question of what economic activity arises for people to participate in for employment. We're already living in an age where most of the useful labour is done by a relatively small percentage of the population. Most of the rest works in various types of service job. Robots like this can replace human workers in entire large segments of those service industries. Sure there are other service jobs, but there are a lot of them that really are of the replaceable with a simple shell script variety. With a little more machine intelligence, the majority of them probably are replaceable that way. Eventually, there won't be any low or no-skill jobs left. Even the jobs fixing the machines will be done by machines. The simple fact is that most people aren't high-skilled labour and even those who are highly skilled or are very, very good at their jobs often can't compete with a custom designed machine (shades of John Henry). The truth is that the new economy jobs that gradually replace the old ones are worse and worse and the typical labourer is going to have to sell their labour on what is increasingly a buyers market.
The problem is that farming, mining, manufacturing, food service, retail sales, warehouse jobs, delivery, construction, etc. can all conceivably be replaced almost entirely by machines. The owners of the machines, farms, mines, factories, restaurants, stores, warehouses, delivery companies, construction companies, etc. will then be the only people producing the tangible things that the consumers truly need, while the majority of the consumers will be working in service jobs producing intangibles that people don't really need.
In other words, we are in danger of transitioning to post-scarcity technology without transitioning to a post-scarcity economy. That leaves most people, at best, working themselves to death in completely unproductive, pointless jobs.
I'm fairly certain that, in microgravity, with my feet strapped down, I could take a 5000 kilogram dumbell sitting at my feet with my hands and lift it up over my head. I couldn't do it very quickly, due to inertia, and I would have to start working against my initial movements at about the halfway mark to stop it from yanking itself out of my hands (or yanking off my hands) at full extension.
not 4.696 gigawatts!
4.696 Megawatt! ~ 5 Gigawatt
off by a factor of 1000
I'm assuming you were educated somewhere where the comma (,) and the period (.) have opposite usage in mathematical notation to the way I use them. It's an unfortunate problem with mathematical conventions. To be clear, when I wrote "4.696 gigawatts" I did not mean: "four thousand six hundred and ninety six gigawatts", but rather "four gigawatts plus six tenths of a gigawatt plus 9 hundredths of a gigawatt plus 6 thousands of a gigawatt". If I had intended to express any number of thousands of gigawatts, I would typically have jumped up to terawatts. If I'd only thought to round up to avoid three significant digits after the decimal point or if I'd written "1,134 square kilometers" instead of just "1134 square kilometers", this could have been avoided as it would have been more obvious from context that I wasn't using the period as a thousands delimiter. On the other hand, other context, such as the way I wrote "113.4 gigawatts" or the way I spelled "kilometer" or just the fact that I'm writing in English on a US-centric website was available.
powerplant ~ 5 Gigawatt
evac zone@100w/m2 ~ 100 Gigawatt
That is correct, and is what I was trying to say. The professor quoted by the original poster was obviously wrong since the evacuation area covered in solar cells would produce approximately 20 times the power of the plant itself (actually only about 10 because I forgot that about half of it is water).
I'm wondering if misunderstanding of my units was why I was actually modded down as "overrated" when the original hearsay post which didn't list any of the facts or math used to reach its conclusions, was modded to +5 informative. But that seems unlikely on Slashdot. Most readers here wouldn't have misread the units the way you did.
In any case, the other point from the original post I didn't address was cost. pi*19000^2 is 1134113990. That's the number of square meters in the evacuation zone, but we'll halve it because of the water to 567056995 square meters. We can just call it 570 million square meters. Covering that with solar cells would surely be expensive. The problem is, the unnamed professor in the original post has set an interesting challenge by saying that covering the evacuation area with solar cells would both produce less power and cost more than the nuclear plant. The problem is that, since the first claim is false by an order of magnitude, do we have to disprove the second claim only for a tenth of the area, or do we have to hand victory to our invisible opponent on half of his claim even though the second claim clearly should only be considered in conjunction with the first?
I'll have to start by saying that I couldn't find numbers for the construction of operating costs for the plant, although there was lots of information about the cleanup costs. New nuclear construction seems to about $5000 per kilowatt though, so we can maybe estimate $25 billion ($25X10^9). Hard to say if that's accurate or not, but it looks like it's certainly going to end up costing more than that in the end. So, if we divide $25 billion by the 570 million square meters for the solar cells, we get about $43 per square meter. It is hard to beat that with solar cells. The best price I could find in a five minute search was $49 and 32 cents per square meter just for the cells and obviously there would be more infrastructure required. Of course, since that's for 10X the production of the nuclear plant, it seem more fair to compare say that you have $430 to spend per square meter, which is much, much more reasonable.
Why would you think soot could replace ozone as a UV blocker?
Because carbon-carbon bonds absorb UV light. It would be temporary compared to the overall length of the UV depletion, of course. The chief survival mechanism would still be sheltering from the light. Things living in high latitudes would have a much easier time. Don't get me wrong, it would be devastating to life in general and there would be mass extinctions and very tough living conditions. But the world wouldn't be sterilized. There are events that could certainly sterilize the world, but the one under discussion, which only has secondary effects on the other hemisphere, wouldn't be enough.
Half the world on fire is still only half the world on fire. This planet is broken up into land masses separated by ocean. There would be a lot of soot and byproducts causing terrible air quality, and probably some "nuclear winter" style weather for a while. Lots and lots of things would die, but certainly not everything. As for the loss of the ozone layer, the soot would probably make up for that. The ozone layer would recover and animals would modify their behaviour to avoid excessive sun damage in the meantime.
I don't even know who this Kaku guy is and I still tend to agree with the assessment that the original post wasn't very well considered.
The concentrations would have to be startlingly high to actually wipe out all surface life. Even then, the life that doesn't breathe, or lives in the ocean, or just isn't as badly affected as large mammals would be just fine.
The life expectancy of a solar panel tends to be better than the life expectancy of a car. Cars and their engines also tend to be expensive to make and replace. A new engine for my sisters car would cost $3,745.00 and is 113 kg. And can produce something like 180 kilowatts optimistically. Of course, it would burn out fast actually producing at that rate. The operational life, actually running, tends to optimistically be about 7 months for a car engine in a car. So, a kilogram of car engine could be said to produce 1.6 kilowatts per kilogram at a cost of $20.80 and lasts 7 months and would consume about A kilogram of thin film solar cell (not counting the glass panels), have demonstrated power levels above 1 kilowatt per kilogram and would almost certainly last for 20 years, which would mean at least 21.4 times the power production of the car. Of course, at the moment, I can't say for sure that the solar panels would cost less than the $445.00 to make it even in lifetime power production with the car engine. Of course, the solar cells wouldn't need the approximately 270 gallons of gasoline the kilogram of engine would use in that time, adding another $810.00 (at an optimistic $3.00 per gallon) to the cost of the car engine power.
Overall it's clear that it's really hard to directly compare these things. Achieving the power density of a car engine with solar cells placed on a car is clearly impossible on this planet. Achieving the abundance of solar power with any fossil fuel is also a clear impossibility since fossil fuels are just solar power stored with miserable efficiency. Personally, I have high hopes at the moment for air-breathing batteries with similar energy density to fuels like gasoline (at least 50% of the density would be all that would be needed), but they also need to have sufficient recharge cycles and low enough cost so that periodic battery replacement plus cost of recharge power doesn't exceed the cost of gasoline. The recharge cycles problem is a technical problem that probably can be solved. Ditto for the cost of recharge power. The cost of replacement batteries, however, is at the mercy of car manufacturers, salivating at the prospect of collecting monopoly rents from captive customers. Pity.
A small car engine is rated at ~200 KW (i.e. Ford Focus Spec at 223 KW)
The rating of a car engine (in your example, ~268 horsepower) is maximum, not typical power output.
What were the numbers on that? The number I can find for the evacuation area is a 19 km radius, which is 1134 square kilometers. Covered in solar cells, assuming about 100 watts per square meter (10% efficiency with 1 kw/square meter insolation), that should produce 113.4 gigawatts. From what I can find, Fukushima Daiichi had a maximum capacity of 7.456 gigawatts with a typical production of 4.696 gigawatts. The power plant site itself was 3,480,299 square meters. So, just the power plant grounds covered in solar cells could have produced 348 megawatts, which would be about 7.4% of its capacity.
Beyond those numbers, I wonder what the real footprint of the plant was. We should ignore initial construction, but we can't ignore that the power plant ran on fuel that required mining and processing. Perhaps all processing was done on site, but the mining and basic refining couldn't have been. How much area was devoted to acquiring the nuclear fuel for the plant? Uranium mining tends to eat some pretty hefty chunks of land. I did a search for info on how much land it actually takes up, but can't find a source that has already compiled a number. It does seem possible that it could use up even more land than the power plants themselves. If it manages to make it to 14:1 for Fukushima Daiichi, that would mean that the land area devoted to generating the nuclear power could be covered in solar cells instead to produce the same power. It's obviously a bit more complicated than that, but it's still very interesting.
Ok, let's do the math. Total electrical consumption (not all energy usage, just electrical) for the US is about 480 gigawatts. Average insolation is about 1 kw per square meter. At 10% efficiency, that means about 100 watts for every square meter of panel. That means you need 4.8 billion square meters of panels. 4.8 billion square meters can fit into a square 69.282 kilometers on a side. That's somewhere between the size of Rhode Island and Delaware.
Even if you expand that to all energy usage, not just electrical, you're talking approximately 3 terrawatts. So, that's about 30 billion square meters of panels. That's a square about 173.2 kilometers on a side. That's somewhere between the size of Maryland and Hawaii.
So, if you actually sit down and DO the math, you can easily cover US electrical requirements and, in fact the total US energy usage (not counting food energy and not considering the fact that much of that energy usage can't currently be converted to electrical) without coming remotely close to covering the US with solar panels.
Of course, if you'd actually done the math on your own claims, you would have realized that, when you claimed that you could "optimistically" supply 7.5% of the US's electrical supply with 0.01% of the surface area, that would mean that you could "optimistically" supply 100% of the electrical supply with 0.133334% of the surface area, or even pessimistically (let's pretend that the difference between "optimistic" and pessimistic is an order of magnitude) with 1.33334% of the surface area.
So, it's pretty clear that you either didn't do the math yourself, or you just decide to bluff. If you meant something else, like that there are logistical problems in covering that much area, then say so.
Conversely, there are others willing to use violence only because of pacifism. Without the majority being peace-loving, we would all be dead from the constant fighting and killing. Obviously pacifism can be taken to the extreme, such as those who refuse to even kill plants and therefore fast themselves to death.
Either way, the term "planetary distances" that was used is clearly not accurate, whether it's two orders of magnitude too small or two orders of magnitude too big.
Well, what can I say to such a rational and well-reasoned argument.
I'm curious. If the grants that pay for your salary and equipment are public money, as you seem to imply, what do you think entitles _you_ to that money? Is there meant to be a quid pro quo, and, if the money is public, who is meant to be the beneficiary?
Generally speaking, it takes them a very, very, very long time to do anything about ponzi schemes. Bernie Madoff ran his ponzi scheme for at least 15 years (by his admission) and probably actually for something like 30 years before anything was done about it.
So, the moon, which is 409,073 kilometers away at its furthest is "planetary distances"? What does that make the distance to Venus, which is 41 million kilometers at its closest or Mars, which is 56 million kilometers at its closest. Seems to me that this is only over about 1% of the shortest distance you could actually consider "planetary distances".