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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

#91

Post by polaritron »

DoctorOetker wrote: post #82
the8472 wrote: post #71

Earlier quoted context omitted.

Civilisation 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 seri…

I 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

Which is also awesome, but not an argument against installing massive, terawatt capacity photovoltaic solar arrays across a desert.

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

#92

Post by sampo »

SECProto wrote: post #83
sampo wrote: post #73

Earlier quoted context omitted.

You should look at section 2.2 in the article. Miami has more cooling degree days (2423) per year than Phoenix (2327) or Las Vegas (1786).

Heat transfer, though, is based on temperature differentials - if Miami is +7degrees every day of the year, and Phoenix is +20degrees only 117 days per year, the energy demands of Phoenix for cooling could very easily be much higher (energy lost through walls, roof would be much higher, as would mass transfer of energy when doors open.) This is irrespective of local construction. Add to this, radiative gain (insolati…

No. No no.

Heat conduction rate is linear in response to the temperature difference [1], so 1 day of 20 degrees difference should give the same total heat loss as 2 days of 10 degrees difference. They also both give 20 degree days, so degree days is the correct measure and should correlate linearly with the energy needed for heating or cooling. The same goes for the heat content in the air that is exchanged due to draft, opening doors etc.

You might have a little bit of a point with sunlight, and humidity. But my guess is that they don't dominate, compared to the conductive and convective heat exchanges.

[1] https://en.wikipedia.org/wiki/Thermal_conduction#Fourier's_l...

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

#93

Post by rapnie »

pmwhite wrote: post #53
state_less wrote: post #29

Earlier quoted context omitted.

Distributed 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/wi…

I 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.

Ammonia might be a better way. Easy to produce, store and transport and contains higher hydrogen density than compressed hydrogen (I think).

http://www.ammoniaenergy.org/

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

#94

Post by lostlogin »

delecti wrote: post #54
pesmhey wrote: post #52

Earlier quoted context omitted.

I’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.

One really good example would be water desalination. I'm sure the neighbors of the Sahara could use a glut of fresh water.

A great use for the power, but also another destabilising thing for them and all the interested foreign powers to fight over.

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

#95

Post by sneak »

whatshisface wrote: post #77
bobthepanda wrote: post #64

Earlier quoted context omitted.

The main issue is that Americans have much more house than Europeans do. The three-car garage McMansion with double-height ceilings and a double-height foyer is a ridiculous amount of space to cool down and heat up for a single household. Nice visualization of that kind of data: https://www.reddit.com/r/dataisbeautiful/comments/7ei5f4/com...

> The three-car garage McMansion with double-height ceilings and a double-height foyer is a ridiculous amount of space to cool down and heat up for a single household. That's definitely not a significant contributor to American energy usage, given that not everyone in America is a millionaire.

McMansions are McMansions because they are cheap to construct and cheap to buy (and surrounded by thousands of nearly identical structures).

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

#96

Post by ahje »

jameskilton wrote: post #3

> 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_territ...

I'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.

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

#97

Post by wohlergehen »

tasty_freeze wrote: post #84
wongarsu wrote: post #34

Earlier quoted context omitted.

For reference for anyone curious: the US has a final energy consumption of 6.0kW per capita, the EU average is about 2.9kW. (2009 data) At that point, China was at 1.3kW/citizen, Africa at half that, India on the level of Africa and the middle East slightly below the EU with 2.3kW. Wikipedia [2] uses world bank data instead which seems to measure differntly, but the relations are roughtly the same. 1: https://www.eea…

I'm confused by your wording and by wikipedia. Watts are a measure of power, not energy. kWh is a measure of energy.

In the same sense as your server has an "energy consumption" of 2000W, i.e. 1W 356*24/1000 kWh/a.

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

#98

Post by samatman »

rapnie wrote: post #93
pmwhite wrote: post #53

Earlier quoted context omitted.

I 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.

Ammonia might be a better way. Easy to produce, store and transport and contains higher hydrogen density than compressed hydrogen (I think). http://www.ammoniaenergy.org/

The biosphere can't handle ammonia accidents at anything resembling the scale of crude oil and natural gas accidents. Methane is the better choice.

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

#99

Post by beerlord »

ebikelaw wrote: post #19
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…

Solar utility installations in California that I’m familiar with employ fewer than 1 person per square km.

Do they have problems with security? Try putting down any large piece of infrastructure in Africa - and careful that it doesn't get carried away.

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

#100

Post by wongarsu »

tasty_freeze wrote: post #84
wongarsu wrote: post #34

Earlier quoted context omitted.

For reference for anyone curious: the US has a final energy consumption of 6.0kW per capita, the EU average is about 2.9kW. (2009 data) At that point, China was at 1.3kW/citizen, Africa at half that, India on the level of Africa and the middle East slightly below the EU with 2.3kW. Wikipedia [2] uses world bank data instead which seems to measure differntly, but the relations are roughtly the same. 1: https://www.eea…

I'm confused by your wording and by wikipedia. Watts are a measure of power, not energy. kWh is a measure of energy.

By saying they use 6kW I mean that each year they use 6kWa (kilowattyears), or 52569 kWh. And 6 kilowattyears per year is the same as 6 kilowatt.
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