5 ms·

Having done the numbers to understand solar (and having designed and built a 13 kW array myself) the hubris exhibited in these conversations about solar continu

Having done the numbers to understand solar (and having designed and built a 13 kW array myself) the hubris exhibited in these conversations about solar continues to perplex me. There simply isn't a comparison between nuclear and solar. Nuclear is a far better solution on all fronts. The reality of solar is very different from the dream of solar. The simplest calculations clearly show this. In order to match the power output of a nuclear power plant you need to build a photovoltaic solar installation of at least seven times the peak power output. In other words, if you want the equivalent of a 1 GW nuclear power plant, the minimum size of your solar array is at least 7 GW peak. And it gets worse, much worse, from there. Why doesn't anyone ever bother to do the math before they become blind champions of technologies they clearly do not understand at a technological level? I understand the emotional connection with wanting to be "clean". Yet, at some point, you have to connect the dream with reality through numbers. Numbers of this type do not lie. The comparison is brutally tilted in favor of nuclear.

ncmncm 4y ago
If you do the math without your thumb on the scale you get a different answer. Everybody knows rooftop solar costs several times utility-scale solar. If you get only 14% duty cycle, you are doing worse than most. Ask the people in Georgia and South Carolina how much value they got for the $15B they were made to spend on their 0W nuke plant.
- robomartin 4y ago
  > Everybody knows rooftop solar costs several times utility-scale solar Nope. Not true. The fact that contractors are raping people doesn't mean that's the cost. The system I installed for about $30K was quoted at $100K. If people pay stupid money for solar that's their problem. > If you get only 14% duty cycle, you are doing worse than most. Not sure where that number comes from. Oh, wait, that's 1/7 th. Ah, you are using my 7x figure to attack my argument? Show me the math that compares any solar system to a nuclear power generator. See, the fact that you used this 14% figure confirmed my suspicion. You really don't know what you are talking about. For all I know you have the mathematical skills to do the numbers, you just haven't taken the time to do it and, as a result, are operating under ideas that can only be described as part of a cult rather than science and engineering. > Ask the people in Georgia and South Carolina how much value they got for the $15B they spend on their 0W nuke plant. By that logic aircraft should not have been developed, ever. If a few failures means a technology is to be avoided most of what we enjoy today would not exist. You are intentionally avoiding the mathematical realities of solar by using a project that was grotesquely mismanaged to sidestep reality. Google says there are 440 nuclear reactors in the world. One or two failed projects due to abject incompetence clearly isn't an argument at all in support of anything other than, don't hire idiots. Do you even know the answer? If I asked you to describe top level requirements for a photovoltaic array that would be the equivalent of a 1 GW nuclear power plant. What would you say? Do you have any idea at all? Can you describe the calculations? Probably not. Most people don't. They like to argue, sometimes passionately, and yet few actually know what they are talking about. So what's your answer? The photovoltaic equivalent of a 1 GW nuclear power plant is calculated as follows: ... I'll wait.
  - quickthrower2 4y ago
    I am interested in the 7 factor. (I have no agenda in this argument). I assume it is because you need to store most of the energy for times when it is not generated, and that storage is not 100% efficient, plus cloudy days and suchlike. You are aiming to not just merely generate the same energy per year as the nuke, but guarantee 1GW at all times. To be a base load?
    - robomartin 4y ago
      Now, this is how a good discussion can be had. Not diverting into irrelevant crap but actually asking the commenter to justify the claim --something I will gladly do here. NOTE: Breaking this into parts because of post limits. ---------------- Power and Energy ---------------- First things first, we have to be careful not to mix energy with power. We all do it out of convenience, yet they are very different things. The differences also affect system-wide technology and economics. Since I can't assume the audience is entirely technical, here's a reasonable analogy for power and energy: Your garden hose is a low power source of water when compared to a firehose. Anyone understands that a firehose can deliver a lot more water per second than a garden hose. Energy is like the amount of water you need to fill-up a swimming pool. You can fill it up with a garden hose, but it could take days. If you use a high power fire hose you might be able to fill up the same swimming pool in seconds. The water distribution infrastructure currently installed in any city is designes such that every home (or a reasonable number of homes) can use their garden hoses and they will all have acceptable flow rates. If every home in a city was specified to have a fire hose, the size and scale of the water distribution systems would be absolutely massive when compared to what we have today. One way to think of this is that power determines how quickly you can deliver energy. Water flow rate determines how quickly you can fill-up your swimming pool. ---------------- The Solar Panel ---------------- What are the realities of a solar panel? Sure, you buy a 325 W panel. Great. How does that behave in the real world, in the context of a system? There are several variables that affect the output of a solar panel: - Mounting angle - Variation of solar radiation based on time of day - Weather (clouds, rain, etc.) - Dirt - Negative temperature coefficient - Wiring losses - Energy conversion losses - Degradation over time I could write pages on the above. I'll limit myself to a couple of elements that have the most impact on power production. ---------------- The Solar Parabola ---------------- If you look at the output of a fixed solar array, regardless of scale, rooftop or megawatt, it will look like an inverted parabola. Here's a picture of that from my 13 kW array: https://i.imgur.com/Fl8ARJd.png https://i.imgur.com/Fl8ARJd.png This is from March of this year. It should be noted that it never reached 13 kW, it peaked at about 10 kW. This is important, but I'll skip over it for now. A nuclear power plant, over the same period of time, would produce constant power for 24 hours. If we are going to scale it down to this graph, we would get 10 kW every second of the day for the full 24 hours. The first thing we need to calculate, then, is the ratio between full power for the solar period vs. what the equivalent nuclear source would deliver. The way you calculate this is to integrate the curves over the period of interest, say from 8 AM to 8 PM. You are comparing the area of a rectangle to that of the parabola that fits within it. The answer to this is surprisingly simple: The ratio is 2/3. In other words, a solar system --of any scale-- rated at the same peak power as a nuclear power plant, will, at best, produce 2/3 (66%) the energy over the same period of time under --and this is important-- ideal conditions. Just using this number, we can calculate that we need to build a 1.5 GW solar array in order to match the daylight energy output of a 1 GW nuclear power plant. ---------------- Power at Night ---------------- That covers you for 12 hours. What do we do for the other half of the day? Batteries, of course. Well, we need extra energy to pump into the batteries so we can use it at night. The 1.5 GW is used-up. If we keep that math simple, that means we need to double our power production capacity. Now we are up to a 3 GW peak power solar system in order to be able to match the energy output of a 1 GW nuclear power plant. I won't cover the cost, scale and realities of such a massive energy storage installation at this time, just remember this is very much a part of the reality of solar --and a very significant one at that. ---------------- Conversion Efficiency ---------------- What I will talk about is the fact that solar arrays require the power conversion systems in order to move energy in and out of batteries and even out to the grid. Current battery charging technologies are nearly 100% efficient, so I'll ignore the small losses incurred going in and out of a battery and over time (self discharge). In order to get in and out of the buildings full of battery packs you will need to use conversion equipment. This will cost about 20% of the energy you produce. Yes, 20% of what you produce will be converted into heat. At the peak of 3 GW, we would be producing 0.6 GW in heat. That's no joke. That's nearly the peak output of a nuclear facility being used to create heat. I won't get into what this might mean in terms of having to provide for cooling. I don't know how this is handled at such massive scales. I just know that 0.6 GW of heat producing power is a very serious number. OK, this means that our system now needs to be upsized yet again in order to compensate for the 20% conversion loss. 3 GW * (1/0.8) = 3.75 GW That's where we are: Without considering other factors, the solar equivalent of a 1 GW nuclear power plant requires 3.75 GW peak power and a train-load of batteries. Are we done? No, not even close.
mayama 4y ago
I used to hold the same opinion that reducing carbon without going nuclear wasn't possible. But, with increasing cost of nuclear power US, EU not categorising nuclear as green and not funding it, India seeing huge delay in their construction of nuclear plants in fleet mode, I came to conclusion that nuclear is not going to be built at scale needed at least in this decade. China is having success in their build out, but China's approach without huge bureaucracy/political overhead is not possible elsewhere. The time for nuclear was 2 decades ago, missing that a decade ago, if there was huge govt investments into it in US or EU. I am hopeful energy storage prices would come down similar to solar in coming years with multiple pilot projects of sodium, flow, thermal batteries expected to come up in few years. Energy storage with offshore wind, solar and solar CSP might be the only option at least for a decade.
- robomartin 4y ago
  > I came to conclusion that nuclear is not going to be built at scale needed at least in this decade. China is having success in their build out, but China's approach without huge bureaucracy/political overhead is not possible elsewhere. You are not wrong here. Nuclear is clearly a better solution. However, if the political forces and dominant ideological framework/cult opposes it, there is no way to make it happen. What we need is a Kennedy-style movement with a goal to "go to the moon" in nuclear power plant terms, in ten years. If everyone is aligned behind a common goal there is absolutely no question that a nation like the US can do it. So can Europe. We are not unique in that sense. It requires clear goals and no-bullshit unity of vision and purpose. To the extent that this is impossible to achieve, yes, we can probably say that nuclear is but a dream. Sadly, almost any construction at scale is impossible in the US these days. In California we have already spent over 100 billion dollars on a high speed train that was supposed to cost 10 billion. They only built about ten miles of low speed track and it doesn't even run. So, yes, again, you are right. So long as incompetence reigns high we can't get out of our own way, nuclear or otherwise.
7952 4y ago
Sure, but technology doesn't exist in a vacuum. You need the political will, finance, a skilled workforce, industrial capacity etc. Solar just wins in those areas. And the maths works fine if you can build that capacity fast and cheap enough.
steeve 4y ago
Thank you. It's getting very tiring to debunk this every time.
- robomartin 4y ago
  Well, yeah, you are right. Sometimes I wonder why I bother at all. There's a sea of ignorance out there, deeply driven by ideological effects rather than science. They are passionate about their beliefs while being almost 100% ignorant about the realities of what they choose to be so passionate and argumentative about. It's a really odd thing. A frustrating thing, for sure. Science is about challenging every single assumption, not being cult members. And yet, these days, if you dare question the beliefs of the mob you are punished/cancelled for it and, at the extremes, suffer potentially serious real-life consequences (anything from losing your job to physical harm). This isn't a society in search of enlightenment and progress. Quite to the contrary. Frankly, if I were a researcher in this field I would probably end-up having to say what they want me to say. Ethics aside, when your entire career, your wellbeing and that of your family depend on the crazies not destroying your life the choices are very limited indeed. I am always surprised that the cult members do not realize that this behavior is, ultimately, self-defeating. History is marked by shifts in beliefs and centers of power. Which means that what someone is aligned with might not be the majority or "power" position in the future. At that moment in time you are going to wish you had extended the courtesy of promoting a civilized and open society to those who you chose to attack at the time simply because you could, because you were a part of a mob. As they say, what goes around, comes around. People tend to forget such simple ideas. The current ideology surrounding climate change, saving the planet, renewable energy, etc. is putrid at best. It's as complete to a full-on delusion as one can get. And yet, the forces at play are so powerful that you'd lose your head if you stick out too far in opposition. Simple example: In order to be able to afford building terawatts of solar and wind generation facilites we need oil, fuel, to be as cheap as dirt. Why? Because construction costs are influenced by the cost of oil and oil derivatives in a non trivial way. The more expensive oil becomes the less affordable it is to build the massive infrastructure improvements we are going to need in order to make any of this a reality. And yet, the ideological hatred for oil is causing all of our costs to double or triple, almost guaranteeing that we will not be able to make advancements at scale in these domains. Crazy. That's ideology for you.

ncmncm 4y ago

If you do the math without your thumb on the scale you get a different answer. Everybody knows rooftop solar costs several times utility-scale solar. If you get only 14% duty cycle, you are doing worse than most. Ask the people in Georgia and South Carolina how much value they got for the $15B they were made to spend on their 0W nuke plant.

robomartin 4y ago
> Everybody knows rooftop solar costs several times utility-scale solar Nope. Not true. The fact that contractors are raping people doesn't mean that's the cost. The system I installed for about $30K was quoted at $100K. If people pay stupid money for solar that's their problem. > If you get only 14% duty cycle, you are doing worse than most. Not sure where that number comes from. Oh, wait, that's 1/7 th. Ah, you are using my 7x figure to attack my argument? Show me the math that compares any solar system to a nuclear power generator. See, the fact that you used this 14% figure confirmed my suspicion. You really don't know what you are talking about. For all I know you have the mathematical skills to do the numbers, you just haven't taken the time to do it and, as a result, are operating under ideas that can only be described as part of a cult rather than science and engineering. > Ask the people in Georgia and South Carolina how much value they got for the $15B they spend on their 0W nuke plant. By that logic aircraft should not have been developed, ever. If a few failures means a technology is to be avoided most of what we enjoy today would not exist. You are intentionally avoiding the mathematical realities of solar by using a project that was grotesquely mismanaged to sidestep reality. Google says there are 440 nuclear reactors in the world. One or two failed projects due to abject incompetence clearly isn't an argument at all in support of anything other than, don't hire idiots. Do you even know the answer? If I asked you to describe top level requirements for a photovoltaic array that would be the equivalent of a 1 GW nuclear power plant. What would you say? Do you have any idea at all? Can you describe the calculations? Probably not. Most people don't. They like to argue, sometimes passionately, and yet few actually know what they are talking about. So what's your answer? The photovoltaic equivalent of a 1 GW nuclear power plant is calculated as follows: ... I'll wait.
- quickthrower2 4y ago
  I am interested in the 7 factor. (I have no agenda in this argument). I assume it is because you need to store most of the energy for times when it is not generated, and that storage is not 100% efficient, plus cloudy days and suchlike. You are aiming to not just merely generate the same energy per year as the nuke, but guarantee 1GW at all times. To be a base load?
  - robomartin 4y ago
    Now, this is how a good discussion can be had. Not diverting into irrelevant crap but actually asking the commenter to justify the claim --something I will gladly do here. NOTE: Breaking this into parts because of post limits. ---------------- Power and Energy ---------------- First things first, we have to be careful not to mix energy with power. We all do it out of convenience, yet they are very different things. The differences also affect system-wide technology and economics. Since I can't assume the audience is entirely technical, here's a reasonable analogy for power and energy: Your garden hose is a low power source of water when compared to a firehose. Anyone understands that a firehose can deliver a lot more water per second than a garden hose. Energy is like the amount of water you need to fill-up a swimming pool. You can fill it up with a garden hose, but it could take days. If you use a high power fire hose you might be able to fill up the same swimming pool in seconds. The water distribution infrastructure currently installed in any city is designes such that every home (or a reasonable number of homes) can use their garden hoses and they will all have acceptable flow rates. If every home in a city was specified to have a fire hose, the size and scale of the water distribution systems would be absolutely massive when compared to what we have today. One way to think of this is that power determines how quickly you can deliver energy. Water flow rate determines how quickly you can fill-up your swimming pool. ---------------- The Solar Panel ---------------- What are the realities of a solar panel? Sure, you buy a 325 W panel. Great. How does that behave in the real world, in the context of a system? There are several variables that affect the output of a solar panel: - Mounting angle - Variation of solar radiation based on time of day - Weather (clouds, rain, etc.) - Dirt - Negative temperature coefficient - Wiring losses - Energy conversion losses - Degradation over time I could write pages on the above. I'll limit myself to a couple of elements that have the most impact on power production. ---------------- The Solar Parabola ---------------- If you look at the output of a fixed solar array, regardless of scale, rooftop or megawatt, it will look like an inverted parabola. Here's a picture of that from my 13 kW array: https://i.imgur.com/Fl8ARJd.png https://i.imgur.com/Fl8ARJd.png This is from March of this year. It should be noted that it never reached 13 kW, it peaked at about 10 kW. This is important, but I'll skip over it for now. A nuclear power plant, over the same period of time, would produce constant power for 24 hours. If we are going to scale it down to this graph, we would get 10 kW every second of the day for the full 24 hours. The first thing we need to calculate, then, is the ratio between full power for the solar period vs. what the equivalent nuclear source would deliver. The way you calculate this is to integrate the curves over the period of interest, say from 8 AM to 8 PM. You are comparing the area of a rectangle to that of the parabola that fits within it. The answer to this is surprisingly simple: The ratio is 2/3. In other words, a solar system --of any scale-- rated at the same peak power as a nuclear power plant, will, at best, produce 2/3 (66%) the energy over the same period of time under --and this is important-- ideal conditions. Just using this number, we can calculate that we need to build a 1.5 GW solar array in order to match the daylight energy output of a 1 GW nuclear power plant. ---------------- Power at Night ---------------- That covers you for 12 hours. What do we do for the other half of the day? Batteries, of course. Well, we need extra energy to pump into the batteries so we can use it at night. The 1.5 GW is used-up. If we keep that math simple, that means we need to double our power production capacity. Now we are up to a 3 GW peak power solar system in order to be able to match the energy output of a 1 GW nuclear power plant. I won't cover the cost, scale and realities of such a massive energy storage installation at this time, just remember this is very much a part of the reality of solar --and a very significant one at that. ---------------- Conversion Efficiency ---------------- What I will talk about is the fact that solar arrays require the power conversion systems in order to move energy in and out of batteries and even out to the grid. Current battery charging technologies are nearly 100% efficient, so I'll ignore the small losses incurred going in and out of a battery and over time (self discharge). In order to get in and out of the buildings full of battery packs you will need to use conversion equipment. This will cost about 20% of the energy you produce. Yes, 20% of what you produce will be converted into heat. At the peak of 3 GW, we would be producing 0.6 GW in heat. That's no joke. That's nearly the peak output of a nuclear facility being used to create heat. I won't get into what this might mean in terms of having to provide for cooling. I don't know how this is handled at such massive scales. I just know that 0.6 GW of heat producing power is a very serious number. OK, this means that our system now needs to be upsized yet again in order to compensate for the 20% conversion loss. 3 GW * (1/0.8) = 3.75 GW That's where we are: Without considering other factors, the solar equivalent of a 1 GW nuclear power plant requires 3.75 GW peak power and a train-load of batteries. Are we done? No, not even close.

mayama 4y ago

I used to hold the same opinion that reducing carbon without going nuclear wasn't possible. But, with increasing cost of nuclear power US, EU not categorising nuclear as green and not funding it, India seeing huge delay in their construction of nuclear plants in fleet mode, I came to conclusion that nuclear is not going to be built at scale needed at least in this decade. China is having success in their build out, but China's approach without huge bureaucracy/political overhead is not possible elsewhere. The time for nuclear was 2 decades ago, missing that a decade ago, if there was huge govt investments into it in US or EU. I am hopeful energy storage prices would come down similar to solar in coming years with multiple pilot projects of sodium, flow, thermal batteries expected to come up in few years. Energy storage with offshore wind, solar and solar CSP might be the only option at least for a decade.

robomartin 4y ago
> I came to conclusion that nuclear is not going to be built at scale needed at least in this decade. China is having success in their build out, but China's approach without huge bureaucracy/political overhead is not possible elsewhere. You are not wrong here. Nuclear is clearly a better solution. However, if the political forces and dominant ideological framework/cult opposes it, there is no way to make it happen. What we need is a Kennedy-style movement with a goal to "go to the moon" in nuclear power plant terms, in ten years. If everyone is aligned behind a common goal there is absolutely no question that a nation like the US can do it. So can Europe. We are not unique in that sense. It requires clear goals and no-bullshit unity of vision and purpose. To the extent that this is impossible to achieve, yes, we can probably say that nuclear is but a dream. Sadly, almost any construction at scale is impossible in the US these days. In California we have already spent over 100 billion dollars on a high speed train that was supposed to cost 10 billion. They only built about ten miles of low speed track and it doesn't even run. So, yes, again, you are right. So long as incompetence reigns high we can't get out of our own way, nuclear or otherwise.

7952 4y ago

Sure, but technology doesn't exist in a vacuum. You need the political will, finance, a skilled workforce, industrial capacity etc. Solar just wins in those areas. And the maths works fine if you can build that capacity fast and cheap enough.

steeve 4y ago

Thank you. It's getting very tiring to debunk this every time.

robomartin 4y ago
Well, yeah, you are right. Sometimes I wonder why I bother at all. There's a sea of ignorance out there, deeply driven by ideological effects rather than science. They are passionate about their beliefs while being almost 100% ignorant about the realities of what they choose to be so passionate and argumentative about. It's a really odd thing. A frustrating thing, for sure. Science is about challenging every single assumption, not being cult members. And yet, these days, if you dare question the beliefs of the mob you are punished/cancelled for it and, at the extremes, suffer potentially serious real-life consequences (anything from losing your job to physical harm). This isn't a society in search of enlightenment and progress. Quite to the contrary. Frankly, if I were a researcher in this field I would probably end-up having to say what they want me to say. Ethics aside, when your entire career, your wellbeing and that of your family depend on the crazies not destroying your life the choices are very limited indeed. I am always surprised that the cult members do not realize that this behavior is, ultimately, self-defeating. History is marked by shifts in beliefs and centers of power. Which means that what someone is aligned with might not be the majority or "power" position in the future. At that moment in time you are going to wish you had extended the courtesy of promoting a civilized and open society to those who you chose to attack at the time simply because you could, because you were a part of a mob. As they say, what goes around, comes around. People tend to forget such simple ideas. The current ideology surrounding climate change, saving the planet, renewable energy, etc. is putrid at best. It's as complete to a full-on delusion as one can get. And yet, the forces at play are so powerful that you'd lose your head if you stick out too far in opposition. Simple example: In order to be able to afford building terawatts of solar and wind generation facilites we need oil, fuel, to be as cheap as dirt. Why? Because construction costs are influenced by the cost of oil and oil derivatives in a non trivial way. The more expensive oil becomes the less affordable it is to build the massive infrastructure improvements we are going to need in order to make any of this a reality. And yet, the ideological hatred for oil is causing all of our costs to double or triple, almost guaranteeing that we will not be able to make advancements at scale in these domains. Crazy. That's ideology for you.