# Giant mirrors in the desert? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [September 26, 2008, 1:32pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318 "2008-09-26T13:32:45Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [September 26, 2008, 1:32pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/1 "2008-09-26T13:32:45Z")
Interesting [article](http://www.bloomberg.com/apps/news?pid=20601109&sid=aESker8lE5B4) about work in Europe regarding the future of solar energy. > [@](#): > > As the sun rises over Seville in southern Spain, its blinding light bounces on a field of 624 mirrors surrounded by sunflowers. > > The moving mirrors reflect sunbeams onto a 115-meter-high white tower that uses the concentrated heat to boil water, making steam that spins an electric turbine 97 times a second. This is Europe’s first commercial solar-thermal-electricity plant, Pretty neat. I’d like to go see that. > [@](#): > > "In six hours, the yearly energy consumption of humanity is delivered as solar energy to deserts,‘’ says German particle physicist Gerhard Knies. He’s devised an audacious plan to erect fields of mirrors in the Sahara Desert and connect North African countries to Europe’s power grid across the Mediterranean Sea. Here’s a mitigation strategy: instead of rebuilding our hurricane-damaged coastal areas with houses, put up some of these ‘mirror fields’ instead. 😛 ---
**Author:** ![constanze](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@constanze](https://boards.straightdope.com/u/constanze)\ **Post date:** [September 27, 2008, 11:01pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/2 "2008-09-27T23:01:58Z")
A guy from the Club of Rome was on TV several weeks back talking about the Sahara plan - I switched on later, so I don’t know if it was mirrors or photovoltaic cells. I think the later because he wanted to couple the energy production with thermic coils on the backside (photovoltaics cells work best in cool temps., and efficiency falls off over 40C), which would provide drinking water for the local population (plus the jobs building and maintaining the plants). They showed maps with how small the necessary area with this plan was - an area the size of Germany and Austria combined would cover the world’s enery needs, and still be lost in the whole Sahara. Technically, no problem, it’s just money and political will that’s lacking. ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [September 27, 2008, 11:11pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/3 "2008-09-27T23:11:17Z")
What do the sunflowers do? ---
**Author:** ![Harmonious\_Discord](https://avatars.discourse-cdn.com/v4/letter/h/74df32/32.png) [@Harmonious\_Discord](https://boards.straightdope.com/u/Harmonious_Discord)\ **Post date:** [September 27, 2008, 11:25pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/4 "2008-09-27T23:25:45Z")
> [@Terrifel](#): > > What do the sunflowers do? Attract the birds so they don’t shit on the mirrors. ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [September 27, 2008, 11:47pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/5 "2008-09-27T23:47:53Z")
> [@Harmonious\_Discord](#): > > Attract the birds so they don’t shit on the mirrors. Ooh, that’s clever! I should try that trick with my bird. Not that she poops on my mirrors, exactly. I just need a nice planter next to my work station. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [September 27, 2008, 11:54pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/6 "2008-09-27T23:54:45Z")
How do I watch TV at night? ---
**Author:** ![constanze](https://avatars.discourse-cdn.com/v4/letter/c/f9ae1b/32.png) [@constanze](https://boards.straightdope.com/u/constanze)\ **Post date:** [September 28, 2008, 12:50am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/7 "2008-09-28T00:50:29Z")
> [@carnivorousplant](#): > > How do I watch TV at night? Turn on TV? Do you mean: “How do use electricity after dark if 100% of energy is produced by solar?” The answer is that there are several possibilities. For one, we wouldn’t go 100% solar, there would be some wind and water left over. Second, you could stagger the solar plants - for example, you have some pretty big deserts in the US where you could produce the energy for yourself, and the Sahara would supply Africa and Europe. Some part of the globe, there’s always sunlight, so you just need longer wires to transport the energy. Third, there are several energy storage options out there beside giant batteries. You can use the surplus electricity during the day to split water into hydrogen and transport and store the hydrogen, and burn it when needed. You can pump water back upwards to a lake, to store potential energy. In the night, the water falling drives a turbine. I’m sure the engineers working on that know more solutions - I just skim the popular press. ---
**Author:** ![Terrifel](https://avatars.discourse-cdn.com/v4/letter/t/c68b51/32.png) [@Terrifel](https://boards.straightdope.com/u/Terrifel)\ **Post date:** [September 28, 2008, 12:59am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/8 "2008-09-28T00:59:02Z")
In a pinch, there’s probably also a way to turn all the bird poop into energy. If those other birds are anything like mine, there should be a LOT. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [September 28, 2008, 12:59am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/9 "2008-09-28T00:59:55Z")
> [@constanze](#): > > split water into hydrogen and transport and store the hydrogen, and burn it when needed. > You can pump water back upwards to a lake, to store potential energy. I was being a smart ass. I wonder which would be the most efficient. ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [September 28, 2008, 1:47am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/10 "2008-09-28T01:47:16Z")
The article talks about storing daytime heat in pools of molten salt, for nighttime use. Anyway, forget the Sahara. The surface of the ocean is truly vast. Now I’m imagining a belt of these solar-thermal plants floating around the equator, connected to a global power grid. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [September 28, 2008, 1:53am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/11 "2008-09-28T01:53:36Z")
> [@levdrakon](#): > > The article talks about storing daytime heat in pools of molten salt, for nighttime use. > > Anyway, forget the Sahara. The surface of the ocean is truly vast. Now I’m imagining a belt of these solar-thermal plants floating around the equator, connected to a global power grid. Anything to keep them all from being in the same place. I think they should be sprinkled all 'round the globe. Wait, they’d better be hurricane-proof. 😉 ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [September 28, 2008, 2:14am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/12 "2008-09-28T02:14:47Z")
> [@NinetyWt](#): > > Anything to keep them all from being in the same place. I think they should be sprinkled all 'round the globe. > > Wait, they’d better be hurricane-proof. 😉 Well, one thing I learned while reading about the proposed space elevator, is the equator is the best place to put it, because hurricanes rarely traverse the equator. So, the equator is about 24,900 miles around, they’ve already got an undersea power transmission cable built about 350 miles long. About 71 of these plants could be built along the equator, 350 miles apart. These plants can’t be more expensive to build than nuclear power plants, can they? We’ve got 439 of those buggers operating worldwide, so building 70-100 solar thermal plants seems within the realm of possibility. I’m not sure how much power that would generate. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [September 28, 2008, 2:26am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/13 "2008-09-28T02:26:39Z")
> [@levdrakon](#): > > I’m not sure how much power that would generate. You could do the whole enchilada, if each plant were about 2400 miles square. Presuming the bit about “Germany and Austria” is correct. ---
**Author:** ![Bad\_Samaritan](https://avatars.discourse-cdn.com/v4/letter/b/ac8455/32.png) [@Bad\_Samaritan](https://boards.straightdope.com/u/Bad_Samaritan)\ **Post date:** [September 28, 2008, 4:29am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/14 "2008-09-28T04:29:34Z")
This technology is pretty interesting too. [Stirling Energy Systems](http://www.stirlingenergy.com/technology/default.asp) The company is using a sun-tracking mirror array to direct the sun’s heat into a collector that drives a Stirling engine, thereby generating electricity. They already have contracts to put up to 70,000 of these dishes in the southern California desert starting in a few years. It’s really impressive stuff. I recently was offered a position with this company. During the interview, I asked what happens if a bird flies through the concentrated beam. The answer was basically “cooked bird”. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [September 28, 2008, 4:39am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/15 "2008-09-28T04:39:11Z")
> [@Bad\_Samaritan](#): > > During the interview, I asked what happens if a bird flies through the concentrated beam. The answer was basically “cooked bird”. :eek: _And it feeds the homeless, too !!_ :thud: ---
**Author:** ![levdrakon](https://avatars.discourse-cdn.com/v4/letter/l/49beb7/32.png) [@levdrakon](https://boards.straightdope.com/u/levdrakon)\ **Post date:** [September 28, 2008, 4:40am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/16 "2008-09-28T04:40:22Z")
> [@NinetyWt](#): > > You could do the whole enchilada, if each plant were about 2400 miles square. Presuming the bit about “Germany and Austria” is correct. I’m a little confused by that. The article states that an area 80 miles by 80 miles could power the EU. I think the EU uses 15-20% of the world’s power. Let’s call it 20%, then 6,400 Sq. miles times 5 is 32,000 sq. miles, which is a lot smaller than Germany and Austria, in order to power most of the world. Did I miss something? It’s past my bedtime. ---
**Author:** ![NinetyWt](https://avatars.discourse-cdn.com/v4/letter/n/cc9497/32.png) [@NinetyWt](https://boards.straightdope.com/u/NinetyWt)\ **Post date:** [September 28, 2008, 4:47am UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/17 "2008-09-28T04:47:50Z")
> [@levdrakon](#): > > I’m a little confused by that. The article states that an area 80 miles by 80 miles could power the EU. I think the EU uses 15-20% of the world’s power. Let’s call it 20%, then 6,400 Sq. miles times 5 is 32,000 sq. miles, which is a lot smaller than Germany and Austria, in order to power most of the world. Did I miss something? It’s past my bedtime. I was coming off of Post #2 ( **Constanze** ’s first post): > [@](#): > > an area the size of Germany and Austria combined would cover the world’s energy needs But I still did it wrong: Size of Germany: 357,021 sq mi Size of Austria: 83,72 sq mi Sum = 440,893 sq mi You mentioned to build 71 plants? 440,893 sq mi/71 plants = OOps! I see what I did - I was dividing the square kilometers, which is 170,230. Then each of the 71 plants would be 2397.6 square kilometers, not square miles. Good catch, **levdrakon**. 😉 ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [September 28, 2008, 3:39pm UTC](https://boards.straightdope.com/t/giant-mirrors-in-the-desert/465318/18 "2008-09-28T15:39:16Z")
Solar 1 & Solar 2 are a lot closer to home for the OP & use similar technology [Solar power plants in the Mojave Desert - Wikipedia](http://en.wikipedia.org/wiki/Solar_power_plants_in_the_Mojave_Desert)