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Modeled impact of large-scale wind and solar farms in the Sahara

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Re: Modeled impact of large-scale wind and solar farms in the Sahara

#41

Post by xyzzyz »

krupan wrote: post #40
xyzzyz wrote: post #32

Earlier quoted context omitted.

Do 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.

You haven't followed the recent Bears Ears controversy, have you? :-)

Not really, though I imagine you'd be able to find 2% of Utah that nobody will care about in particular. I love Utah as much as anyone, especially in winter, but I wouldn't want all of the US look exactly like Utah -- and the whole US is about as large as Sahara is.

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#42

Post by krupan »

krupan wrote: post #40
xyzzyz wrote: post #32

Earlier quoted context omitted.

Do 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.

You haven't followed the recent Bears Ears controversy, have you? :-)

Here's another example. I grew up in Washington state. We have dams on a lot of rivers in the Northwest generating clean renewable energy before anyone had ever heard of climate change (Grand Coulee is the most famous). They literally did change the barren desert of Eastern Washington into a fertile farming breadbasket with the irrigation water and power they provide. Despite that, there are people who hate them because they changed the rivers into a series of lakes and are threatening the wild salmon population.

Pick any part of the Sahara and transform it and some species unique to that area, some native people, some curious weather pattern, some unique geologic formation will be lost and people will be upset.

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#43

Post by sulam »

TeMPOraL wrote: post #38
krupan wrote: post #23

Earlier quoted context omitted.

Sorry, 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.

Question is, what do you care more about - the unique geography, or people living there?

Very few people live in the Sahara. However, to your larger point, many people live in Europe and the Middle East, and being able to power their cities could in turn obviate the need to emit quite a large amount of CO2, potentially affecting the entire planet in a positive way.

I would give up some portion of the Sahara (up to all of it) if it meant the planet doesn't warm 4 degrees. Of course that's easy for me to say -- I don't live there. :/

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#44

Post by infogulch »

sandworm101 wrote: post #15

What 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…

This line of thought interested me so I went and looked for some numbers.

The 10 sqkm 648 MW Kamuthi Power Plant [1] was built in record time in 2016 at a rate of 11 MW/day with a crew of 8500, which comes to about 2 months. This project is many orders of magnitude larger, lets be generous and say there is a 20x economy of scale in this project above Kamuthi: 100 sqkm / mo / 8500 crew. With 100 such crews (a lot) it would still take 3/4 of a century just to install 9M sqkm, and the installation alone would employ ~1M people. Wow.

According to [2], the degradation rate varies between 0.5%-1% per year. Using a generous 0.1% as an estimate for maintenance would put it at 9000 sqkm needing maintenance/replacement every year which according to the estimates above would only require ~10 full-time crews from above. Still ~100k people, a big city for sure, but not millions.

Another thing to consider is that a project of this size would be decades in the future and I imagine it would heavily employ automation, so dropping a couple zeros off the number of people required could be quite feasible.

[1]: https://qz.com/india/854483/worlds-largest-solar-plant-kamut...

[2]: https://medium.com/@solar.dao/everything-you-need-to-know-ab...

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#45

Post by xyzzyz »

abecedarius wrote: post #20
nine_k wrote: post #16

Earlier quoted context omitted.

Generating 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.

How would you go about it? Lots of high-voltage lines, or is there something else that'd make more sense for this unusual setup?

Standard 800 kV DC line from Algeria to Berlin (2400 km) would incur less than 10% transmission loss.

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#46

Post by kryogen1c »

I 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.

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#47

Post by nwallin »

satya71 wrote: post #33
weberc2 wrote: post #28

Earlier quoted context omitted.

I’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.

I don't have the numbers. But intuitively, AC should be less energy as it's energy transfer. Heating is usually directly adding energy to the living environment. You can get heating using heat pumps (some southern US homes have this type) but it doesn't work very well when it's too cold outside. Europe should have more heating than US, with it's more northern location.

Electric heaters are more efficient than traditional air conditioning units. Transferring heat from inside a 80F house to the 110F air outside is not very efficient, only about 30-60%. On the hand, an incandescent light bulb is a ~99% efficient heater. The only energy that is "lost" is the light which is radiated out the window. Space heaters and electric radiators are 100% efficient.

Additionally, heat pumps are can be spectacularly efficient when it's warm outside (in which case, who needs a heater) but are still more than 100% efficient when it's cold outside. Waste heat is still heat, after all. The problem with heat pumps is that the quantity of thermal they can put into a house drops dramatically when it's cold outside. When it's extremely cold outside, the only heat you're added to the place you're trying to heat is the waste heat from the unit itself.

Swamp coolers can be very efficient "air conditioners" but they only work in extremely dry environments. Heat exchangers that pull cold water from a nearby cold lake (for instance, there are data centers in Chicago that use the lakewater from Lake Michigan) can be highly efficient, but there's a lot of infrastructure involved, and they only work on warm land near cold water.

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#48

Post by jopsen »

spacenick88 wrote: post #13
Analemma_ wrote: post #9

Earlier quoted context omitted.

If 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 household…

Almost 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.

Exactly,

As we see efficiency increase as well.. things are not as bad. Sure energy consumption will increase, but not to US levels.

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#49

Post by notfromhere »

kryogen1c wrote: post #46

I 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.

It'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

Re: Modeled impact of large-scale wind and solar farms in the Sahara

#50

Post by xyzzyz »

krupan wrote: post #42
krupan wrote: post #40

Earlier quoted context omitted.

You haven't followed the recent Bears Ears controversy, have you? :-)

Here's another example. I grew up in Washington state. We have dams on a lot of rivers in the Northwest generating clean renewable energy before anyone had ever heard of climate change (Grand Coulee is the most famous). They literally did change the barren desert of Eastern Washington into a fertile farming breadbasket with the irrigation water and power they provide. Despite that, there are people who hate them beca…

I'm quite familiar with the dams, I live in Washington myself, and visited them multiple times. I agree that someone will always be upset, but this is generally true about every change ever. The point is to do changes that are most beneficial to the most, don't carry extremely serious side effects, and are net win over the alternative, which in this case is keeping burning coal. There's still plenty of coal left in Roslyn fields, and if not for the dams, it would probably continue to be extracted today.
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