7 ms·
> One kilogram of uranium-235 (50 cm^3) can theoretically produce about 20 terajoules of energy. One square kilometer of solar panels can theoretically produce
by margalabargala 3y ago
> One kilogram of uranium-235 (50 cm^3) can theoretically produce about 20 terajoules of energy. One square kilometer of solar panels can theoretically produce the same amount (as 50cm^3 U235) in a day.
Does the US have more 50cm^3 sized blocks of U235, or more square kilometers of land with low land values and high annual insolation?
There's an estimated 6 million tonnes of mineable uranium reserves in the world [0]. Of which 0.72% is U-235, so we have a worldwide reserve of 43200 tonnes, or 43.2 million Kg U-235.
Arizona is about 300k square kilometers. If we covered an area 10% the size of Arizona in solar panels, then they would have produced more energy than all the world's known U-235 in just four years. And would continue producing after those four years are up.
[0] https://world-nuclear.org/information-library/nuclear-fuel-cycle/mining-of-uranium/world-uranium-mining-production.aspx https://world-nuclear.org/information-library/nuclear-fuel-c...
- Turing_Machine 3y ago> If we covered an area 10% the size of Arizona in solar panels And what are the various Friends of Rare Bugs and Small Furry Animals groups doing in the meantime? I joke, but even I would balk at the environmental impact of that. Certainly it's going to be greater than any equivalent nuclear installation. > Of which 0.72% is U-235 Fortunately we're not limited to U-235. With breeder reactors, there's enough nuclear fuel to run human civilization for billions-with-a-b of years.
- jodrellblank 3y agoCover 4,000 square miles of the USA in surface car parks[1] and that's freedom. Suggest covering 11,000 square miles of desert in solar panels which don't stop land being used for grazing or crop growing or insects or wildlife, and that's environmental distruction that "even" you would balk at. [1] https://www.archdaily.com/976069/when-5-percent-of-the-united-states-is-covered-by-parking-lots-how-do-we-redesign-our-cities https://www.archdaily.com/976069/when-5-percent-of-the-unite...
- internetter 3y agoSpeaking of parking lots, it's not a terrible idea (and it's already been done before) to put solar panels above parking lots
- Turing_Machine 3y agoFalse dichotomy. The people who will be screaming about covering the desert with solar panels are exactly the same people who scream about covering the land with car parks. Exactly. The only energy source radical environmentalists like is one that exists only in a fantasy. As soon as it starts being built, it becomes evil. Note that they're already up in arms about windmills killing birds. Also, covering the desert is definitely going to change the local environment. At a minimum, every joule that goes into the power transmission lines is a joule that will not be available for use by the desert ecosystem.
- angiosperm 3y agoThe desert ecosystem wastes almost all of its incoming joules. The most valuable commodity in a desert is shade.
- Turing_Machine 3y agoIf you were a cactus you'd no doubt disagree.
- angiosperm 3y agoAnd you have discussed this with a cactus? Or are you still just making things up?
- AlgorithmicTime 3y ago[dead]
- internetter 3y agoI want to make clear that I am not arguing against solar. My belief is that nuclear is an important piece of a much larger puzzle. Wind is not reliable, and for solar to match the figures you provided, we would need to figure out storage, so lets diversify our portfolio :)
- tzs 3y ago> Wind is not reliable Surface wind is not reliable. I've seen proposals to put turbines on large kites or gliders tethered to the ground. There's pretty much always strong winds over most of the United States somewhere between the surface and 10000 feet.
- wkat4242 3y agoHmm what to do with the torque from the windmill though. Perhaps it could have counter rotating propellers to cancel it out. Otherwise it would entangle itself in the anchoring cable. Also, a failure scenario would mean tonnes of windmill crashing down from high altitude. Hmmmmm
- tzs 3y ago> Also, a failure scenario would mean tonnes of windmill crashing down from high altitude. Hmmmm 10000 feet is less than 2 miles. Even in high winds it wouldn't get more than a a couple or miles or so before hitting the ground. There are plenty of places in the US where you could fly where it would be centered over a 6 mile diameter circle that contains no people or valuable buildings except for people and buildings that are part of the power facility.
- jodrellblank 3y agoFiguring out storage is hard if you think in terms of Lithium Ion grid-scale batteries, or mountains for pumped hydro, but[1] puts forward the idea of synthetic natural gas generated by solar panels. That can be pumped into existing national gas grids, existing gas storage, and sent into existing gas power stations to generate power in quiet times. The article says that solar power has dropped from $100/Watt in 1976 to $0.50/Watt by 2016, and that instead of slowing down as the low hanging fruit has been picked, that process is speeding up since 2011 when Solar started to become cheaper than other forms of power generation, which changed the feedback loops and is bringing in much more demand which brings more investment, research and production, than before when it was an expensive little-used alternative. This is a linked graph of solar growth compared to International Energy Agency's World Energy Outlook predictions: https://rameznaam.com/wp-content/uploads/2020/05/IEA-Solar-Growth-Forecasts-vs-Reality-Simon-Evans-Carbon-Brief.jpg https://rameznaam.com/wp-content/uploads/2020/05/IEA-Solar-G... In each of 2006, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2018, the IEA predicted deployment of solar would stop accelerating (line going up) and steady off into consistant growth (flatline on that graph). Every year they have been very quickly wrong, and the 2019 predition of flatline is so wrong that by 2021 actual production of 190GW was WAYYYY off the top of that chart. At this rate we may not need to figure out storage nearly as much as we think. > "What people have missed is that reaching cost parity on fuel synthesis will unlock huge new demand centers [and trigger an acceleration in demand/investment/research/cost decline of solar created synthetic fuels]." [1] https://news.ycombinator.com/item?id=32197012 https://news.ycombinator.com/item?id=32197012 (article rather than comments)
- _aavaa_ 3y agoIt’s worth noting that the dichotomy you set up isn’t quite right. The land use for solar and wind isn’t an exclusionary zone. The area around a wind turbine can be used same as before (most often as farmland) without a negative impact on its productivity. And the same is true for solar. In fact, a growing number of agro-voltaic projects are seeing a net positive on crop yields from solar panels due to the increased shading and decreased temperatures.
- orangepurple 3y agoIs it possible for solar panels to be semi-transparent so crops can still thrive underneath?
- philipkglass 3y agoYes it is: https://www.pv-magazine.com/2021/07/02/transparent-solar-panels-for-agrivoltaics/ https://www.pv-magazine.com/2021/07/02/transparent-solar-pan... “Combining two usage modes based on Insolight’s optical micro-tracking technology, these modules focus light on high-efficiency solar cells,” Insolight said in a press release. “When aligned, the optical system can generate energy (E-MODE), but it is also possible to unalign it to ‘leak’ the light (MLT-MODE). The solar modules therefore act like a ‘smart’ shade adjusting the amount of light they let through.” This makes it possible to optimize the photosynthesis of plants during the seasons and reduce the negative impact of high summer heat on the yields and quality of agricultural products, while recovering the rest of the light in the form of electricity. Starting from July, the panels will be tested for four years on a 165-square-meter surface area. They will replace protective plastic tunnels on strawberries and raspberries. “Dynamically adjusting the light transmitted to the plants paves the way for increased protection from climate variations and possible increases in crop yields thanks to the matching of the light to the needs of the plants and the lowering of the temperature during heat waves via the shading effect,” said Bastien Christ, head of the berries and medicinal plants group at Agroscope. A similar project using different module technology: https://www.pv-magazine.com/2023/10/31/baywa-re-starts-building-agrivoltaic-project-in-france/ https://www.pv-magazine.com/2023/10/31/baywa-re-starts-build...
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- evilos 3y agoI remember reading some article that said we could offset all of human emissions by painting Vermont stark white or something along those lines. Covering a desert in solar panels seems like the exact opposite of that plan.
- margalabargala 3y agoIf you ignore all other variables, then of course the situation looks like what one variable would make it do. Would covering a desert in solar panels cause more thermal solar absorption in that area than would otherwise happen? Yes. But if we're optimizing for "offsetting the heating effect of human GHG emissions", then installing 4.5TW of solar (about 4x what has been installed worldwide to date) would have a much more positive effect. The world currently has 1.1TW of solar installed, producing about 6% of all electricity. So our new installation would be on its own capable of supplying 25% of global electricity usage. The corresponding drop in GHG emissions from the shutdown of coal, gas, and oil power plants would far outweigh the fact that part of the desert has been turned black.
- evilos 3y agoHas this actually been quantified? Earth's albedo is a critical factor in the portion of the sun's energy that is rejected into space, just as GHG incidence in the atmosphere is. In theory, darkening a portion of the Earth with high albedo (snow, sand) is worse than darkening a portion of the Earth with low albedo (roads, roofs, forest). Then it should be better to use a greener area for solar panels so long as the capacity factors would be similar.
- angiosperm 3y agoMillions of square kilometers of the arctic are being "darkened" by loss of sea ice. Nothing humans can do can approach even a tiny fraction of that.
- evilos 3y agoMany people would argue that humans did cause this loss of sea ice. Also I don't see how that justifies adding to the effect? Especially if we don't know can't compute the trade off? I'm sure someone has done that work but my it didn't immediately jump out at me during a cursory search.
- sandworm101 3y agoThere is way way more uranium than that. It is surprisingly common. And harvesting it from seawater opens up a supply that dwarfs any mining concept. https://en.wikipedia.org/wiki/Uranium_in_the_environment https://en.wikipedia.org/wiki/Uranium_in_the_environment >> Uranium is a naturally occurring element found in low levels within all rock, soil, and water. This is the highest-numbered element to be found naturally in significant quantities on earth. According to the United Nations Scientific Committee on the Effects of Atomic Radiation the normal concentration of uranium in soil is 300 μg/kg to 11.7 mg/kg. ... It is considered to be more plentiful than antimony, beryllium, cadmium, gold, mercury, silver, or tungsten and is about as abundant as tin, arsenic or molybdenum. How uranium ore becomes fuel rods: (Actually a rather simple process imho.) https://youtu.be/9x7DozCqLxU https://youtu.be/9x7DozCqLxU https://youtu.be/c7ehyxRBMbw https://youtu.be/c7ehyxRBMbw
- keep_reading 3y agoNuclear is renewable for the same reason geothermal is renewable, and you can get uranium out of seawater for the same price as mining it https://www.tiktok.com/@nuclearsciencelover/video/7092135813848337706 https://www.tiktok.com/@nuclearsciencelover/video/7092135813...
- rajamaka 3y agoWhy do people bother mining it?
- deleted 3y ago[deleted]
- mpweiher 3y agoBecause mining it is relatively cheap. So cheap, in fact, that it is economical to throw away >95% of the fuel rather than try to burn it all or recycle it. Fuel costs are 10% of the cost of nuclear electricity. The vast majority is financing.
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- burnerburnito 3y ago>"or more square kilometers of land [...]" Technically you need to factor in the fact that a nuclear plant can be built relatively near the places where its power will be consumed; some mass of solar power in Nevada is highly inefficient for powering New York or Virginia, even if you built HVDC lines to cut down on total line losses, so you'll need to pick land tracts reasonably near battery banks that would in turn be near cities.
- angiosperm 3y agoInventing imaginary problems does not contribute to the discussion. Please use facts.
- stephenr 3y agoJust as well New York and Virginia have oodles of open ocean right at their doorstep to run multi-gigawatt wind farms I guess huh?
- fastball 3y agoWind isn't reliable.
- gustavus 3y agoYeah and all those people on the other side of the Appalachians can just take a hike, why do they need power anyway. They brought the problem on their selves with their dirty coal mining habits time for them to pay the price.
- stephenr 3y agoThe comment I replied to talked about getting power from Nevada to New York. I'm not American so I had to look at a map but it seems like the other side of the Appalachians from New York is... Ohio? Is there something about Ohio that means they have no atmospheric wind nor natural sunlight?
- thelastgallon 3y ago40 million acres are used to grow corn for ethanol. This is 162,000 square kilometers. This can produce 3.24 exajoules of energy. Also, solar panels don't need any land. There are so many places we can install solar without 'consuming' land. They can be roofs, floating on tops of lakes and reservoirs with the added benefit of preventing evaporation, agrivoltaics combined with farmland, vertical panels, superfund sites, deserts, along the highways, etc.
- rainsford 3y agoFor all the concern about land use for renewables, it really feels like subsidized ethanol has got to be the most wasteful use of energy investment dollars in terms of farmland used and every other possible metric. It's very interesting to think about using that money and land for other energy generation uses.
- rcxdude 3y agoyes, biofuel is a colossally bad idea and it should have been obvious to everyone involved right from the start.
- mlrtime 3y agoOne counter point is that these fields can easily be turned into crops to feed the citizens of the country in an emergency. Solar panels not so much. Also, there was already infrastructure in place to easily maintain this energy source. Not saying this is a reason to keep the subsidies, but I'm sure it made sense at the time.
- marcosdumay 3y agoThe thing about mineral reserves is that they only make sense when you add the price-point to the number. There is enough Uranium on the planet for a few centuries. Make it a few millennia if you breed it, and lots and lots of millennia if you expand your reactors to use other fuels. But most of it is way more expensive to get than what we use today... what actually makes very little difference for the final costs.
- fooker 3y agoOne kg of Uranium is significantly easier to transport compared to the solar energy obtained in a corner of Arizona or Utah though.
- kortilla 3y agoAnd what happens when it gets dark? Solar is cheap, storage is not.