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Modeled impact of large-scale wind and solar farms in the Sahara
- deleted 8y ago[deleted]
- jameskilton 8y ago> The wind and solar farms simulated in the study would cover more than 9 million square kilometers and generate, on average, about 3 terawatts and 79 terawatts of electrical power, respectively. This study is looking at a combined farm size that's almost as large as all the land mass in the US. https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area https://en.wikipedia.org/wiki/List_of_U.S._states_and_territ...
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- ant6n 8y agoThat's a lot of terawatts. In 2013, the world used about 18 TW on average. https://en.wikipedia.org/wiki/World_energy_consumption https://en.wikipedia.org/wiki/World_energy_consumption
- wongarsu 8y agoThat seems a bit excessive, considering that the world energy consumption is only about 18 terawatts (and only about 3 terawatts of that are electrical right now).
- Analemma_ 8y agoIf countries like China, India, Malaysia, Nigeria etc. start to have per-capita energy use close to that of the United States, global energy consumption could easily double or triple even without any increase in population. I said "if", but I really should say "when", because this is what's expected to happen as these countries modernize and start getting things like air conditioning on the same scale as US households. 79 TW of capacity will become a necessity sooner than you think.
- logfromblammo 8y agoAlso, if that much excess would otherwise be wasted, we could always use it to smelt aluminum, form it into big tanks, attach standard docking rings, fill them up with water, and launch them into a designated band of refueling orbits. Those would almost certainly be useful later in space technology development.
- wizardforhire 8y agoOr condense air and harvest co2 for sequestering.
- spacenick88 8y agoAlmost no one in Europe has per-capita energy use anywhere close to the US, so why would China? And I don't think it's just that we have less AC, though that's surely the strongest contributor.
- xyzzyz 8y agoWe have less AC, but we have more heating, which is more energy intensive than AC.
- weberc2 8y agoI’m doubtful about both of these claims (Europe has more heating than the US and that heating is more energy-intensive than AC). The latter seems particularly hard to believe given how efficient heating is compared to A.C.
- 0xCMP 8y agoIt may have to do with where the heat comes from? I live in southern most areas of US, but from what I understand it's common for heating to use Gas/etc. instead of electricity. Therefore they use less "energy" (i.e. Electrical energy) All just a theory
- pesmhey 8y agoI’d like to offer a comparison that may put it into a different perspective for you. Imagine saying that a 1 TB hard drive is excessive, 20 years ago. Sure, contemporaneously, but we sure did find some useful ways to put all that excessive hard drive space to use.
- delecti 8y agoOne really good example would be water desalination. I'm sure the neighbors of the Sahara could use a glut of fresh water.
- lostlogin 8y agoA great use for the power, but also another destabilising thing for them and all the interested foreign powers to fight over.
- delecti 8y agoUnfortunately I think you're probably right. It's really a shame how many otherwise great things we miss out on because people suck. Constant "this is why we can't have nice things."
- the8472 8y agoCivilisation is to a large extent constrained by available energy, which is why new energy sources have lead to industrial revolutions. As long as you're not spending other resources on it excessively any massive amount of energy surplus can be put to good, previously uneconomical and fantastical-seeming uses. Given enough energy you could regulate the entire biosphere by brute force. And if you ever want to get serious about colonizing space a stupendous amount of energy has to be spent just lifting people and materials into orbit.
- DoctorOetker 8y agoI totally agree with you, but if any of the many variations of space elevator becomes possible, you can balance the energy and momentum of mass moving up, by mass going down perhaps returning tourism or valuable materials mined off earth
- polaritron 8y agoWhich is also awesome, but not an argument against installing massive, terawatt capacity photovoltaic solar arrays across a desert.
- DoctorOetker 8y agodid it occur to you ... perhaps I wasn't arguing against terawatt capacity PV solar arrays across desert? ;)
- mirimir 8y agoWell, the extra energy can be used for CO2 capture :) And the win of an arable Sahara would be just incredible.
- PostPost 8y agoIn this case, "large" means almost the entire Sahara, which is 9.2 million square kilometers. Africa is huge. 79 terawatts of power in the study is not unreasonable, given the population growth. https://en.wikipedia.org/wiki/Sahara https://en.wikipedia.org/wiki/Sahara
- nine_k 8y agoGenerating terawatts is not unreasonable. But transportation of it out of North Africa would be almost as big an effort as building the solar farms in question.
- abecedarius 8y agoHow would you go about it? Lots of high-voltage lines, or is there something else that'd make more sense for this unusual setup?
- nine_k 8y agoI suppose that a lot of such transmission lines should be superconductive, if only to help put enough electricity through physically more narrow channels. Even with modern high-temp superconductors, it's a lot of expensive infrastructure, a lot of protective redundancy, and a lot of maintenance.
- TeMPOraL 8y ago> Even with modern high-temp superconductors, it's a lot of expensive infrastructure, a lot of protective redundancy, and a lot of maintenance. Which means lots of local jobs, which may not turn out so bad in the short term.
- state_less 8y agoDistributed generation seems like it would make sense (with current tech). Italy and Spain could help here. Maybe you could go from Tunisia to Europe, but supplying African countries seems more attainable. It'd be nice if you could turn the energy into a gas like methane, pull CO2 out of the atmosphere in the process. Good for the atmosphere and you could transport gas over long distances. https://en.wikipedia.org/wiki/Power-to-gas https://en.wikipedia.org/wiki/Power-to-gas
- pmwhite 8y agoI wonder if hydrogen is practical to transport in large quantities. My guess is no. Your idea of methane, if it could be done efficiently, seems more likely.
- sunstone 8y agoSo in the Sahara that would probably mean all solar and a few batteries. Wind turbines would have maintenance issues from the sand storms.
- ahje 8y agoI'm quite sure the availability of cheap energy would result in quite a boost for most countries around this complex. As a result their energy consumption would most likely increase a lot.
- rossdavidh 8y agoWhile interesting, I have my doubts as to the reliability of any prediction model for a case such as this. It would be a case quite a bit outside the historical data which the prediction model is based on, and it's not like weather and ecological systems are nicely linear and well-behaved systems to predict.
- wongarsu 8y ago>"The greater nighttime warming takes place because wind turbines can enhance the vertical mixing and bring down warmer air from above," the authors wrote. That's actually a very interesting effect. I guess the votices generated by wind farms quite beneficial in a desert region. It would be interesting to see what effect wind farms have on desertification. Given that two large factors are fertile ground blowing away and desert sand being blown onto fertile land, I imagine wind farms might be beneficial for slowing down desert growth.
- reaperducer 8y agoI guess the votices generated by wind farms quite beneficial in a desert region. Unless you're an ectothermic creature (like a lizard, tortoise, snake, etc...) which relies on the cool of night to hunt food and find water.
- e40 8y agoYeah, I was thinking that the cool temps at night are necessary for condensation. Without it, the plant and animal life in the region could be devastated.
- BurningFrog 8y agoIf we're talking about deserts, there is next to no plant and animal life, and part of the goal of this would be to change that.
- reaperducer 8y agoYou are grossly misinformed about deserts.
- village-idiot 8y agoHumans tend to know less about environments that kill us rapidly.
- sandworm101 8y agoWhat they do not model is the local effect of the cities that will need to be built to service all these panels. 9,000,000 square KM is a gigantic area. Millions of people will be needed to maintain these farms. Those people will need to either live locally or be transported regularly. The study should model how the presence of those people in such a relatively underpopulated area will impact local climate. 1 person per km2 = 9million people. But I'd bet you would need a couple dozen people for every km2 of solar farm, and associate infrastructure, meaning perhaps 100 millions people. And then all the people to provide services to those people ... this is like building a few new countries from scratch.
- ebikelaw 8y agoSolar utility installations in California that I’m familiar with employ fewer than 1 person per square km.
- sandworm101 8y agoAnd how do they keep all those panels clean? Who maintains the transformers when they break? Who swaps out the panels as they reach their life expectancy? It isn't just the night watchman, but the entire community of people involved in any large outdoor installation.
- ebikelaw 8y agoLike any utility, you don't need a guy just hanging around waiting for the transformers to explode. You truck him in every 50 years when that actually happens. It's time domain multiplexing, essentially.
- mikeyouse 8y agoThe cleaning is largely a solved problem too.. You don't need 50 $10k/year people with squeegees, you just need one person in a $50k truck. https://www.alibaba.com/product-detail/China-Road-tunnel-wall-cleaning-vehicle_60770674771.html?spm=a2700.7724857.normalList.5.63a52b09SAEP3y https://www.alibaba.com/product-detail/China-Road-tunnel-wal...
- krupan 8y ago"A new climate-modeling study finds that a massive wind and solar installation in the Sahara Desert and neighboring Sahel would increase local temperature, precipitation and vegetation. Overall, the researchers report, the effects would likely benefit the region." Beneficial to who or what? Beneficial in what ways?
- xyzzyz 8y agoYou can continue reading the article to learn the answers, you know.
- krupan 8y agoSorry, I think the point I was trying to make was, do we really want to transform this unique geography? I live in Utah and if someone came here and said, "you know all this red rock and sand in the south, we could change that into a lush green landscape," there'd be massive opposition to that idea.
- kurthr 8y agoThe Sahara desert is in fact growing (some 10%)... likely due to global warming. So it's constantly transforming in any case. https://www.livescience.com/62168-sahara-desert-expanding.html https://www.livescience.com/62168-sahara-desert-expanding.ht...
- xyzzyz 8y agoDo you think there would a massive opposition if someone came here and offered changing 2% of Utah into lush green landscape? I believe this change would be welcome, as people like some variety. Now, area of Utah is 2% of Sahara's area, so we could literally transform some patch of Sahara of the size of Utah, and still have 98% of it untouched, and get enough electricity to power most of Europe.
- krupan 8y agoYou haven't followed the recent Bears Ears controversy, have you? :-)
- ngcc_hk 8y agoCan the energy used to water desalination from the sea ?
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- kryogen1c 8y agoI have always been alarmed that I've never seen the weather effects of solar and wind power discussed - they are by definition removing energy (randomly) from the global climate system. As one of the least understood and most complex systems that _drastically_ impact our lives, this should be cause for concern.
- notfromhere 8y agoIt's not like the sun runs out of shine. I think the impacts of renewable energy is several factors lower than our current C02 based economy
- clairity 8y agothat energy loss to solar and wind power is a miniscule percentage of the energy available, which is provided by the sun and most of which gets radiated away anyways. no need to worry about it for another 5 billion years or so.
- kryogen1c 8y agoThe concern is not the output of the sun, but energy moving in an unplanned (and unplannable fashion). In other words, solar panels shade ground that would have been sunned. Windmills change atmospheric differential pressure by removing windspeed. The best case scenario is these changes are negligible, but that is a luck-based result. We have no idea because global climate is not effectively modelable.
- peterashford 8y agoYou're worried that we haven't discussed the results of something that you admit is not effectively modelable?
- kryogen1c 8y agoYes. Just because something is difficult to model doesn't mean the outcome/results can't be wildly dangerous. We should still try and guess the impacts of our actions, but it seems like no one is concerned.
- strainer 8y agoI would not have guessed that the solar arrays beneficial effect on precipitation is dependent on them not being too efficient and so releasing more heat than bare desert (which is very reflective). From the article - "The precipitation increase in our solar farm experiments is due to the relatively low conversion efficiency of the panels (15%, typical current conversion efficiency for photovoltaic panels), which results in albedo decrease. However, if solar panel efficiency and the associated effective albedo are high enough to lead to an albedo increase relative to the background environment (as, for example, a 45% efficiency would), the climate impact would be surface cooling with precipitation suppression, similar to the impact of overgrazing in the desert. Assuming an intermediate conversion efficiency higher than 15% for solar panels (e.g., 30% efficiency) results in negligible albedo change and, thus, insignificant climate impacts." [^] http://science.sciencemag.org/content/361/6406/1019 http://science.sciencemag.org/content/361/6406/1019
- DoctorOetker 8y agoI still consider it a win even if solar panels reach 45% efficiency: surplus energy can be used to desalinate and transport seawater for irrigation, or by condensing it from air (releasing the heat of condensation)