Geophysical constraints on the reliability of solar and wind power worldwide

mixes renewable capacity and storage depending on the country: US -- Generation 1.5 times the capacity needed, 12 hours of storage, wind and solar have a power supply gap of 15% when the goal is to tolerate 10 hours of power outage. Germany -- Generation 3 times the capacity needed, 12 hours of storage, wind and solar have a power supply gap of 60% when the goal is to tolerate 10 hours of power outage. The larger the power supply gap, the more additional dispatchable power that must be provided. [1] https://www.nature.com/articles/s41467-021-26355-z

recycling), that means we need 6TWh/year of grid scale battery production, which at current rates of increase in battery production, we are 5-7 years away from. Even ignoring the fact that 12 hours is insufficient, you're making the following assumptions: 1. The production of batteries will sextuple in the next 5-7 years. 2. 100% (or close to 100%) of battery production will be dedicated to grid storage. 3. Electricity consumption will remain static. The first one may or may not pan out. Battery production is already bottlenecked by resource extraction, and it's unclear if the rate of extraction can keep up. The nature of extraction is that once easily accessible deposits are exhausted, companies shift to the harder-to-access deposits. This is only economically viable if cost increases enough to incentivize that investment. The HN crowd tends to assume that everything adheres to Moore's law, but that doesn't work in reality. The price of steel, for instance, doesn't exponentially decline. The second two are certainly not true. EV are predicted to make up the vast majority of battery sales. Redirecting batteries to grid storage would necessitate delaying EV adoption, ultimately increasing emissions. Stationary storage accounts for a small fraction of battery production (https://rmi.org/the-rise-of-batteries-in-six-charts-and-not-...). Electric vehicles only account for a bit under 20% of vehicle sales worldwide. With many countries slated to stop sales of ICE vehicles in the next 5-10 years, we're still looking at most future battery production going to satisfy EV demand even if it grows to 6TWh per year as per your assumptions. And electricity use will certainly increase. Both as poorer countries develop and start deploying air conditioning and other electricity consumption. And as other sources of primary energy consumption is shifted to electricity. Remember, electricity generation only makes up ~40% of total energy consumption. The remainder will have to be converted to electricity as part of full decarbonization.

use to provide all Tesla Master Plan solar + wind: Solar: 12 Hawaii's Wind: 1 Hawaii (area of all islands) or, Solar: 30% of California Wind: 2.5% of California Annual Operations and Maintenance costs : Solar: 1.33 times wind O&M Wind: 1.00 Initial investment in factories: Solar: $ 11 billion Wind: $212 billion Storage required for 95% reliability: Solar: >12 hours Wind: 3 hours Wind requires 4x less batteries, with all the cost, recycling and ecological advantages this delivers. Build supply chain origin: Solar: Heavy reliance on China Wind: Diverse Long term supply chain (maintenance, parts, etc.) origin: Solar: Heavy reliance on China (forever) Wind: Diverse The above numbers come from parsing through Tesla's Master Plan Part 3 (MPP3) and several of their references. Of course, this is US-centric, yet, I think it scales well to other parts of the globe. It isn't a case that combining solar and wind can't provide a good solution. It's that idea that wind has enough advantages that it can provide reliable clean power generation all by itself (with storage). In other words, grid-scale solar would not be necessary at the kind of scale proposed by MPP3. I need to emphasize the above because there's a tendency to point out that the combination of wind and solar works very well. And, yes, it does. However, that misses the point entirely. The point is that geographically distributed grid-scale wind with storage does not need any solar to reach 95% reliability (power availability) [0] Table 2. In short, it seems wind would have lower land utilization, operation and maintenance costs, startup investment, 1/4 the storage requirement, ecological impact (based on only needing 1/4 of the batteries) and, finally, the potential for a more favorable supply chain, both for construction and long-term maintenance. Home-scale solar and storage has nothing to do with my comment (after all, we are talking about nuclear power). I am only referring to grid scale. Home-scale solar makes sense on many fronts. NOTE: This is the only document outside of MPP3 I used to generate some of the above: [0] https://www.nature.com/articles/s41467-021-26355-z

unmet electricity demand—or in some cases 1 loss of load event—in 10 years (i.e., 99.97% or 99.99%, respectively)19. https://www.nature.com/articles/s41467-021-26355-z Even leaving 1% of demand unfulfilled amounts to multiple orders of magnitude more frequent electricity production shortfalls. Figures like "fulfill 99% of electricity demand" might sound promising, until you compare against the standards of reliability modern society expects of the electrical grid. And that's in Australia, quite literally the best-case scenario for renewables. By comparison, in Germany even 12 hours of storage would only satisfy 80-90% of demand.

fulfilling demand 99% of the time is a 20x increase in blackouts. Also, even just 12 hours of storage globally would be 30,000 GWh of storage. That's still about 50 times the amount of batteries produced annually. The reality is that hydropower is the only feasible form of grid storage.

are typically very high (e.g., targeting <2–3 h of unplanned outages per year, or ~99.97%). Resource adequacy planning standards for “1-in-10” are also high: in North America (BAL-502-RF-03), generating resources must be adequate to provide no more than 1 day of unmet electricity demand—or in some cases 1 loss of load event—in 10 years (i.e., 99.97% or 99.99%, respectively) So no, even with 12 hours of storage and 50% overcapacity, we'd have an unacceptably unreliable grid. Also, your linked article is not modelling a carbon-free grid: > Graham says that the CSIRO modelling showed that at very high levels of wind and solar, a maximum of half a day’s average demand was needed for storage. In some areas of the grid, only around three hours might be needed. What are these "very high levels of wind and solar"? How much of the remaining demand is satisfied by fossil fuels? The article doesn't say.

that the world can easily do wind with minimal, if any, input from China. This, I think, is good. However, the real issue, in my opinion, is the operations and maintenance column. Deploying unimaginably large amounts of solar means that nearly 100% of that business will go to China. I am in manufacturing, have been all my life. One way or the other, we end-up in China. This also means that the entire world will forever be dependent on China for the ongoing maintenance of these systems. I can't even imagine what this means in dollars per year. I think I can say it could represent the single largest transfer of wealth into one nation in the history of civilization. I don't hate China at all. They've been very smart, worked very hard and, in about fifty years, achieved a transition from an agrarian economy to a technology superpower. This is remarkable. My comment about dependence on China is more about balance than anything else. We need to live in a world where, well, to put it concisely, no single society has the entire planet by the balls. That's where we are headed with China. I don't think that's a good thing at all. We need to develop other areas of the world so that other societies and cultures can benefit from international trade and elevate their standards of living. I have a feeling that mass world-wide reliance on solar will effectively shift an equally massive range of economic opportunity to China in more ways than we can imagine today. Wind, on the other hand, I think, can be made to be far more equitable. > One key point is that solar is very predictable and pairs well with lithium ion batteries that cycle daily to meet demand for most of the globe that doesnt have dark winters Yes and no. On the pairing with batteries. This is a study of 39 years of data from 42 different countries: https://www.nature.com/articles/s41467-021-26355-z Table 2 is very interesting (it take some effort to get comfortable with it). One of the interesting findings is that, after overbuilding both technologies by 1.5x, wind + 3 hours of storage gets you to 95% reliability (you only go dark 5% of the time). Solar, with the same three hours of batteries, only gets you to about 70%. Even if you bring solar to 12 hours of storage, you only get up to about 85% reliability. It is easy to understand why at a basic level: Solar is shut down half the time, when the sun isn't up. That's the baseline from which we have to start and make something that is as close to 100% reliable as possible. In other words, it's a losing proposition from the start. My argument is only about grid scale. Local power on top of a roof is a different story. You can't have wind turbines there, solar is the only option as a supplement for the grid. On that topic, I have noted elsewhere that I am not anti-solar at all. I am simply trying to understand if what I am observing in the data for grid scale systems is correct. I designed and built a 13 kW array on my property. Before installing this system I, as many do, saw solar in some idealized form. I guess I never gave it a second thought. Now, after many years of operating this system and viewing the data, I have a very different opinion. This speaks to your comment about solar being very predictable. My opinion matched yours before I had solar. Today, I would say, sure, only under perfect laboratory conditions. A friend of mine is considering an off-grid system (self sufficiency). He asked me for guidance on this based on my experience. Here's a quick explainer video I recorded for him. I didn't record this with the intent of making it a refined public presentation, keep that in mind as you watch it. The reality of solar, in this context, is likely to horrify most people who still hold an idealized view of the technology. Again, I am not saying it is a bad technology, I am simply suggesting we are not necessarily exposing the realities that a town or city might have to content with if solar is the predominant source of energy. https://www.youtube.com/watch?v=TCyKqSmS33A

weather. > Ongoing maintenance costs (the numbers are in table 5, but essentially wind requires 2x the maintence cost of solar on shore, and the ratio is worse off shore). I actually did look at this, including reviewing the source of the numbers (link is on table 5). The way I read it is the maintenance cost is about the same. Why? Wind (onshore, not even considering offshore) delivers 3.07 TWh/GW, while solar only gets you 1.33. That's a ratio of 2.3. In other words, you install 2.3 times less wind (in power rating) than solar for the same energy output. The operating and maintenance costs are given in terms of kW per year. Therefore, when we include the fact that wind requires 2.3 times smaller installation (again, in terms of power), the total O&M cost is actually lower for wind. Quick calculation, using 1 MW wind for simple numbers, the equivalent solar would require 2.3 MW. The annual O&M cost for each would be: Solar: 2.3 MW $36,731 Wind: 1.0 MW $27,570 Solar, per unit power, is 1.33 times more expensive to maintain. > Material used in construction (table 15), the amount of concrete used is 6x greater for wind than solar. I did follow this link as well (sorry, my comment would have been a book if I included every step). Here's the source document: https://eitrawmaterials.eu/wp-content/uploads/2020/04/rms_fo... Table 2 (page 21), in the above document, shows that wind can be constructed with as little as 243,000 t/GW. Table 4 (page 39), calls for 60,700 t/GW of concrete for solar. Yes, there are other numbers. They are based on the LDS/MDS/HDS scenarios as described on page 8. Frankly, some of this feels hand-wavy to me. That's just my opinion, I can't put numbers to it. The numbers, again, are related to installed capacity in GW. Using the ratio I used above, we can then compare concrete requirements for installations that deliver the same amount of energy: Solar: 2.3 GW * 60,700 t/GW = 139,610 t Wind: 1.0 GW * 243,000 t/GW = 243,000 t In other words, for the same energy output, wind, today, requires 1.7 times more concrete. I am not sure that's a negative. We have to go back to the idea that wind requires 5.2 times less land. Without diving too deep, preparation of the terrain and all of the activities related to construction, operations and maintenance cannot be ignored. My sense --and I have not done any calculations on this at all-- is that the actual comparison might have solar dwarf wind in terms of costs and consequences. Going back to my prior post, full solar (no wind) in the US would require an area the size of 12 Hawaii's. The full wind scenario (no solar) only one Hawaii. Imagine trucks and heavy machinery delivering materials, transporting components, plowing, leveling, creating access roads, etc. I don't think this is a trivial difference. However, there's another difference that I found to be shocking. I had never considered this, I guess. This goes back to the Master Plan document, table 12. The initial investment in factories to build solar and wind are: Solar: $212 billion Wind: $ 11 billion That is an absolutely massive difference and one that, in my opinion, cannot be ignored. That's nearly 20 times the cost for solar. I also wonder what the material, energy and land area utilization intensity might be for these factories. > why concentrate more on wind instead of trying to optimize a balanced approach over all of the variables? I don't think there's anything (physics, engineering) that requires a balanced approach, other than the obvious, which is that solar and wind need 100% backup for some portion of the energy cycle. This can be achieved through overbuilding, batteries and a few additional technologies. I am suggesting we don't need a menu of absolutely every technology in order to meet demand. The advantages of wind, as I see them: - Far greater reliability - 4x less batteries delivers significantly higher reliability - 5.2 times less land area - 20x less manufacturing (factory build) investment - 3/4 the Operating and Maintenance cost of solar per delivered GWh (energy) - Potentially far lower reliance on Chinese supply chain I have gone over most of these in my comments. I'll just highlight that the lower battery requirements against increased reliability is likely an important metric. The study below shows the results of looking at 39 years of data from 42 countries. https://www.nature.com/articles/s41467-021-26355-z Figure 2 shows that wind, overbuilt to 1.5x and with just 3 hours of storage, in the US, achieves a reliability of approximately 95%. Solar, under the same conditions, only gets you about 70% availability. In other words, you go dark 5% of the time vs. 30% of the time. That's when other technologies would have to be brought in to supplement. Oddly enough, the same table shows what happens if you go up to 12 hours of storage. It doesn't really buy you much at all. Neither does combining solar and wind. You gain a few percent against the case of wind only. Yet, you have to build fully two redundant systems, with solar requiring over five times more land. That doesn't make much sense to me. When wind alone can easily get to 95% reliability with 4 times less batteries, that's got to make people take pause and possibly rethink what we are saying about solar.

reasonable prediction. It is interesting to see Master Plan Part 3 (MPP3) continue to confirm I wasn't too far off. I have also modified my stance over time about what this meant. In simple terms, this prediction would be equivalent to having to build over a thousand new 1 GW nuclear power plants. This is never going to happen. I doubt we can (or want to) even build a hundred of them. MPP3 assumes we build zero additional nuclear. Not sure I agree with this idea. However, it isn't a deal-breaker. After reading this paper a while back I developed the thought that wind might just be a far more intelligent source of clean power than nuclear (definitely) and likely solar. https://www.nature.com/articles/s41467-021-26355-z Table 6 (page 20) is interesting to me. We have to build a 5,338 GW (again, power) generation capacity in order to reliably produce the energy we will need. Our current capacity is 1,200 GW. This highlights the enormity of the project. We have to replace the current generation systems with clean systems and build an additional 4,138 GW on top of that. That is over three times current capacity on top of what we have. Again, just highlighting the enormity of the task so it doesn't get lost in the numbers. When looking at table 6 I immediately focused on what I will call the "specific energy generation factor" for each technology. I'll define this as Annual Generation / Installed Capacity. In other words: How much energy do we get per year for each GW of installed capacity for each technology. Here are the numbers (based on table 6): Onshore Wind: 3.07 TWh/GW Offshore Wind: 3.31 TWh/GW Solar PV: 1.33 TWh/GW Nuclear: 7.06 TWh/GW Hydro: 4.07 TWh/GW Once we look at installation cost solar and onshore wind are very similar. Yes, table 5 shows a difference in operating and maintenance costs. I'll take their word for it. My sense is these costs would decrease, perhaps significantly, through the natural optimization that happens as a technology is deployed and matures. My point is that, to me, wind seems like a far better idea that solar on many fronts. It is far more reliable on its own. Without going too far, solar is off approximately 50% of the time and requires 100% reliable backup even if a nice fluffy white cloud flies over a panel. Wind requires far less overbuild and somewhere in the order of a factor of four less storage to be over 95% reliable. Jumping to table 14, we discover how much land is required for each technology: Solar: 3.9 acres/MW or 3900 acres/GW Wind: 0.75 acres/MW or 750 acres/GW Wind requires 5.2 times less land. Going back to table 6, solar and onshore wind combined contribute 10,106 TWh. How many GW of installed capacity would be required to supply that much energy if all of it came from a single technology? Solar: 7,598 GW Wind: 3,292 GW How much land? Solar: 29,632,200 acres = 12 times the area of Hawaii (all islands) Wind: 2,469,000 acres = 1 time the area of Hawaii Anther comparison of land requirements: Solar: 30% of California Wind: 2.5% of California I am not categorically stating that wind is a better option. I am simply raising the question. To me it seems that solar might not be the best idea. It requires far more land, storage and overbuilding. The cost is about the same. And, apropos to the crazy times we navigate today, a massive proportion of the supply chain for solar is in China. NOTE: Sad that I have to make this request. Another sign of the times. It's OK to disagree with with me. If you do, please use numbers, not insults. There's just too much of that crap going around these days. I actively want to know where I might be wrong. That only happens in the context of a conversation, not a feces throwing match. Oh, yes, and it is also OK to ask questions. For example "How did you calculate...?" or "Why do you think ... is more important than ...?", etc. Again, sad that I feel it is important to explain how to disagree and have a conversation these days. PS.: Hope I didn't make any dumb errors in the math. Please let me know.

serious questions about solar. This is where the 95% figure for wind comes from. And, BTW, figure 2 also shows that without overbuilding capacity both technologies are challenging. There are ways to look at using distant solar and wind to provide for power holes. For example, have wind power brought in from 500 to 1000 miles away. The idea is you know there's a seriously good probability for the weather being different enough that you cover the power holes at location A using power from location B. That's great. The question then becomes: How do residents of location B deal with their issues when you are sucking-up their power from location A. No simple answers to this other than to say that both solar and wind have to be overbuilt and require 100% backup --of some form, I don't care what type-- for when they cannot deliver. And so your question is perfectly valid and one that really needs to be on the table, front and center. I have asked it before. It is usually met with attacks and insults. It can take many forms, the most basic being: If you need full 100% reliable backup available at a moments' notice, 24/7/365, are these truly the best technologies for the job? I have argued that nuclear is a solid solution with 100% availability and the power density to deliver our needs. That is met with even more violent attacks and insults. Apparently I am somewhere between a really stupid person and a criminal for suggesting any of this. Having devoted a significant effort towards understanding the many intricacies surrounding these issues, my thinking has morphed over time. I used to think we had to consider deploying a massive amount of nuclear power (somewhere beyond 1000 new power plants) for a full transition to electric vehicles and homes. That, of course, is as close to impossible as one can get. I think a sensible path might be to focus on the 95% reliability of wind (which is far better than anything solar can achieve) and provide that 5% backup with regionally shared nuclear power and other power sources. We would still need hundreds of nuclear power plants built over the next, say, 30 to 50 years. Difficult, yes. Here's the shocking reality of a transition to full electrification (homes and transportation): We have to, at a minimum, TRIPLE our power generation and transport capacity. Why triple? Well, if we are going to go clean, you have to replace all of our existing power generation with 100% reliable clean alternatives. That means we need to build 1200 GW of new clean power generation. As we do this, we shut down what we don't want (if we can). Next, we need another 1200 GW --at a minimum-- to power a full fleet of electric ground vehicles. If we start talking cargo ships and aircraft, we are likely at another 1000 GW or far more. The task, then, is to build somewhere around 3000 to 4000 GW of new clean power generation sources. They have to be 100% reliable, or you need to grossly overbuild to compensate for that. The, question, then: Can we do this? In 25 years? No way. How about 50 years? Maybe? Tough to say. It sure a hell isn't happening in ten or fifteen, which makes the dramatic claims being made by politicians and their supporters nothing less than ridiculous. [0] https://www.nature.com/articles/s41467-021-26355-z

solar? The table shows the "39-year average estimated reliability (% of total annual electricity demand met)". In other words, what percentage of the time the lights in your town will stay on given a power generation and storage technology mix. Here's what it says (comments mine): Without storage ($): Solar alone: 54% (half the time you go dark) Wind alone: 82% (wow) With 3 hours of storage ($$): Solar alone: 66% (meh) Wind alone: 85% (nice) With 12 hours of storage ($$$$$): Solar alone: 81% (finally) Wind alone: 88% (better) Overbuilt by 1.5x with just 3 hours of storage ($$$$): Solar alone: 70% (meh) Wind alone: 95% (double-wow) Wind alone, without storage, is massively better at delivering reliable power than solar. The city goes dark 18% of the time, rather than 46% for solar. If we just add 3 hours of storage, wind goes up a few percent, same for solar. Not too exciting. The real find is what happens if we overbuild generation capacity by 1.5x and add just 3 hours of storage: Wind goes up to 95% reliability, while solar only 70%. 95% RELIABILITY FOR WIND! 70% RELIABILITY FOR SOLAR! That is a massive find, one deserving saying it out loud. The city is dark only 5% of the time with wind, vs. 30% with solar. Both require backup for the percentage they cannot deliver reliably. Wind requires massively less backup. Is wind cheaper, simpler, easier to maintain over the long term? Not sure, I would have to do the math on that. The questions are compelling enough for me to explore further. There's another element that is often not explored: Solar requires almost 100% reliance on China for the entire supply chain. Does wind technology inshore most of the supply chain? The world today is a nasty place. If the US, Europe and other regions can inshore manufacturing and technology, rather than send trillions of dollars to China, this would be a good thing, something worth pursuing. So, again, I ask: Given the above. Why use solar? Your article, once again, supports my perspective. > you are consistently disrespectful, arrogant and condescending. You are confusing those things with stating what I know because I am sure of it. There is a difference. A professor isn't disrespectful, arrogant and condescending because she asserts what she knows to be true. Neither is a doctor, lawyer or, for that matter, an engineer. I urge you to, once again, stop the insults, fire-up Excel and do some math before posting. I just used the numbers you provided to show that questioning solar as the best option likely has merit. Open for discussion? Of course. Get to the point where you have done enough work to have a reasonable understanding of the subject matter. Then, use numbers. Not insults. Anyone would gladly have a conversation with you under those condition. None of this means solar is useless and should not continue to scale. It does mean we really need to be objective and check our assumptions at the door. My guess is that, yes, of course solar is worthwhile and valuable. Yet, no, it is unlikely to be the best solution for everything. It needs backup, lots of it. It needs wind. Lots of it. And it probably needs fossil and nuclear generation to be able to deliver constant, consistent and reliable power. Nobody is likely to install wind turbines atop their homes, so, yes, definitely, solar has a place, likely on our roofs. I would question solar at scale because wind looks to be massively better on first inspection. This needs a further look at the numbers and reality of wind. I am being very patient here and trying to teach you a few things anyone would find valuable. First, there's the matter of treating others with respect and learning to have a conversation. We all benefit from this. Second, we have to be careful about our assumptions. We should not dismiss others because we don't like what they are saying. Above all, before aggressively challenging anyone, we have to do the work --which can be difficult and time consuming. You have to keep in mind that someone with the scientific training who is presenting arguments based on math and physics like has devoted a non-trivial amount of time to understanding the problem. One cannot challenge someone coming from that perspective without doing the work first. Third, don't take this discussion personally. I am simply trying to guide you into understanding that your approach isn't constructive and does not lead discovering the truth through dialogue. Anyone can be wrong and anyone can be right. I've been in both those corners. Yet, we are never going to discover where we are if we decide to just slap each other silly. That's the opposite of constructive. [0] https://www.nature.com/articles/s41467-021-26355-z