Scientists help make deserts into solar-energy hubs

[Agloco]

I thought that with all of the US green energy debates on this forum, it would be of interest to some to see what is transpiring in other parts of the world. My apologies if this is being discussed already.

This article comes from PhysicsToday but it is non-technical. It gives some insight into the plans and challenges involved with delivering solar energy to Africa and Europe. It also delves into an interesting exchange being proposed between the two regions.

http://physicstoday.org/resource/1/phtoad/v64/i7/p21_s1?bypassSSO=1


Swap solar energy from the Middle East and North Africa (MENA) for scientific equipment or access to facilities in Europe. Boost the scientific level in the region through exchanges and collaboration. Establish in Cairo a joint European–MENA solar energy center for research and implementation of relevant technologies. Power the region’s scientific facilities with solar energy.
Those are among the ideas that some 250 scientists, policymakers, and others came up with in May at the Solar Energy for Science symposium held at DESY, the Electron Synchrotron laboratory in Hamburg, Germany. The atmosphere at the symposium “was really unbelievable. It was a festival,” says DESY director Helmut Dosch. “You tend to get drunk from the ideas, but we will have to find out what is realistic.”
The symposium was the inauguration of a scientific initiative inspired by and connected to Desertec, a foundation working to realize its founder’s dream: harnessing solar energy from deserts to supply much of the world’s energy demands.

[Wild Cobra]

Well, I think the desert is the ideal place for such projects. The biggest problem is trying to send the electricity any large distance. Now I'm not in favor of the molten salt platforms. Yes, they have some great upsides, but the downside if the salts ever freeze in the piping...

A facility would need to be 1/2 gigawatt or larger in my view, and make use of a DC power line of 500 KV or more to be practical for any distance.

[TDMVPDPOY]

Well, I think the desert is the ideal place for such projects. The biggest problem is trying to send the electricity any large distance. Now I'm not in favor of the molten salt platforms. Yes, they have some great upsides, but the downside if the salts ever freeze in the piping...

A facility would need to be 1/2 gigawatt or larger in my view, and make use of a DC power line of 500 KV or more to be practical for any distance.

bullshit

if the decepticons can store energy in them energy cubes...i see why not we cant do that store energy into cubes...

[Wild Cobra]

bullshit

if the decepticons can store energy in them energy cubes...i see why not we cant do that store energy into cubes...
This can be a good thread if we stay serious.

[Agloco]

Well, I think the desert is the ideal place for such projects. The biggest problem is trying to send the electricity any large distance. Now I'm not in favor of the molten salt platforms. Yes, they have some great upsides, but the downside if the salts ever freeze in the piping...

A facility would need to be 1/2 gigawatt or larger in my view, and make use of a DC power line of 500 KV or more to be practical for any distance.

I think that for domestic use, the molten platforms are a good idea. It also has the advantage of providing power around the clock, a real boon for countries that struggle to provide power for basic infrastructure today. Obviously, molten platforms wont work for export. The DC cables being proposed are a great investment for Europe IMO, especially in light of the fact that nuclear power is falling out of favor.

What I'd like to know is how large a .5GW facility would need to be. It sounds as if multiple locations are being planned and this is a good thing, but I'm curious as to how the pilot location will perform and exactly how much investment is required on the part of the EU.

[Wild Cobra]

What I'd like to know is how large a .5GW facility would need to be. It sounds as if multiple locations are being planned and this is a good thing, but I'm curious as to how the pilot location will perform and exactly how much investment is required on the part of the EU.
For the solar collection, I don't know. That part could be several locations within a few hundred miles of the facility that would change it to high tension DC for long distance transport. My whole point is that without scaling large, the costs of long haul energy transport do not pay off. The higher the voltage, the less power you have due to restive losses. You cannot transmit AC power long distances either, because the power lines start to act as antennas and the power radiates out.

I've been inside the power facility in The Dalles, OR years ago that takes the power from nearby hydroelectric dams on the Columbia River and ships the power to Los Angeles. At the time, they used 30' tall mercury vapor rectifiers. Now they use solid state devices, and have increased their capacity to 2.1 giga-watts if I recall. My thoughts are this proven technology would be useful to collect energy from desert areas and ship as much as a thousand or two miles.

[Agloco]

For the solar collection, I don't know. That part could be several locations within a few hundred miles of the facility that would change it to high tension DC for long distance transport. My whole point is that without scaling large, the costs of long haul energy transport do not pay off. The higher the voltage, the less power you have due to restive losses. You cannot transmit AC power long distances either, because the power lines start to act as antennas and the power radiates out.

Sure, I wasn't suggesting otherwise. I was simply pointing out that as a start point, a .5GW plant might be ambitious depending on the infrastructure needed. I'm sure the EU can foot the bill, question is, how much real estate does that eat up? I'm also certain that if it involves multiple locations, that would require proportionally more land. I have no idea, just musing here.



I've been inside the power facility in The Dalles, OR years ago that takes the power from nearby hydroelectric dams on the Columbia River and ships the power to Los Angeles. At the time, they used 30' tall mercury vapor rectifiers. Now they use solid state devices, and have increased their capacity to 2.1 giga-watts if I recall. My thoughts are this proven technology would be useful to collect energy from desert areas and ship as much as a thousand or two miles.

Just flew over that a week ago on my way to and from Vancouver. It's quite impressive even from 35 thousand feet. I wonder how much climate would affect solid state devices (if at all). The Dalles/Los Angeles is a bit different than Tunis/Frankfurt, the latter seeing more extreme changes along its route. Do you happen to know anything about that?

[Wild Cobra]

I incorrectly remembered. The capacity is now 3.1 GW.

Wiki: Pacific Intertie (http://en.wikipedia.org/wiki/Pacific_Intertie)

Click to view Google maps:

http://i181.photobucket.com/albums/x262/Wild_Cobra/satellite%20view/CeliloConverterStation-2.jpg (http://maps.google.com/maps?ll=45.594041,-121.113625&spn=0.024444,0.037551&t=h&z=15)

[Wild Cobra]

Just flew over that a week ago on my way to and from Vancouver. It's quite impressive even from 35 thousand feet.
Yes, that power facility is visible from high altitudes. I lived in The Dalles for about a decade. I miss the beautiful summers there. There is a lake about 10 miles east I used to go. The Dalles being small, very low light pollution. Hot summers and clear nights. The banding of the Milky Way is so beautiful.

I wonder how much climate would affect solid state devices (if at all).
It doesn't. They are housed inside a building.

The Dalles/Los Angeles is a bit different than Tunis/Frankfurt, the latter seeing more extreme changes along its route. Do you happen to know anything about that?
If they are actually proposing such a plan, the Mediterranean is the perfect ground plane. Only need a single overhead conductor. I think the best route would be to construct towers from the sea floor, connecting through Sicily and across Italy. The route would be almost twice the distance from The Dalles to LA. I bet they have the option of undersea cables with modern dielectrics, but wow... if something ever went wrong.

[boutons_deux]

A Solar Power Plant in the Sahara Could Power All of Europe

http://blogs.discovermagazine.com/80beats/2008/07/23/a-solar-power-plant-in-the-sahara-could-power-all-of-europe/

[Wild Cobra]

$70 billion is peanuts compared to what we spend. Now if the US politicians really wanted a stimulus instead of bailing out the elite, we would do something like that on our deserts, and build a HVDC line infrastructure.

[Agloco]

A Solar Power Plant in the Sahara Could Power All of Europe

http://blogs.discovermagazine.com/80beats/2008/07/23/a-solar-power-plant-in-the-sahara-could-power-all-of-europe/

:tu

Gives a good idea of the scale involved. I wonder which countries would be willing to give up that kind of real estate?


$70 billion is peanuts compared to what we spend. Now if the US politicians really wanted a stimulus instead of bailing out the elite, we would do something like that on our deserts, and build a HVDC line infrastructure.

Agreed. It's a good opportunity for the EU to get it's power issues in line, and a good pportunity for African nations to pull on the industrial and technical capabilities of the EU to further their own infrastructure. I see a win-win here, provided that political instability doesnt threaten those power stations.

[boutons_deux]

"which countries would be willing to give up that kind of real estate"

Morocco, Algeria, Tunisia, Libya, Egypt are almost all Sahara. Another string of unstable, Muslim countries with a natural resource in great abundance, all capable of holding Europe hostage by threatening to turn off the power.

I don't think real estate is the problem, except for finding land that is solid and closest to the Med, not pure sand.

It's royalty fees and who owns the facilities, very much like contracts in oil-producing countries.

Then there is the question of sinking $100B into sand and expecting the structures to be stable oriented and maintainable.

[Agloco]

"which countries would be willing to give up that kind of real estate"

Morocco, Algeria, Tunisia, Libya, Egypt are almost all Sahara. Another string of unstable, Muslim countries with a natural resource in great abundance, all capable of holding Europe hostage by threatening to turn off the power.

I don't think real estate is the problem, except for finding land that is solid and closest to the Med, not pure sand.

It's royalty fees and who owns the facilities, very much like contracts in oil-producing countries.

Then there is the question of sinking $100B into sand and expecting the structures to be stable oriented and maintainable.

Well my point was that i could see the EU demanding some way to ensure that their power doesn't become a hostage to political unrest. Maybe through an arrangement whereby EU troops or police forces would be permanently stationed in those countries.

So my question was within that context and should have been included with the original remark.

[boutons_deux]

Letting foreign troops occupy and have total control over solar plants in the desert is very probably a non-starter with Muslim countries.

Unless they are really ignorant of oil production, they understand why almost oil countries have PSC, production sharing contract where the foreign companies get paid a share of the oil that is fully own by the country.

A similar deal would be for the Sahara country to own the electricity and pay the developers of the solar plant and electricty exporters with a share of the electricity while retaining full ownership of the electricity and the solar plant (and the on/off switch).

[Agloco]

Letting foreign troops occupy and have total control over solar plants in the desert is very probably a non-starter with Muslim countries.

Unless they are really ignorant of oil production, they understand why almost oil countries have PSC, production sharing contract whee the foreign companies get paid in share of the oil that if fully own by the country. A similar deal would be for the Sahara country to own the electricity and pay the developers of the solar plant and exlectricy exporters with a share of the electricity while retaining full ownership of the electricity and the solar plant.

Lol. Yeah i didn't think that was a realistic scenario. But what lengths would the EU go to to ensure uninterrupted power?

I think that any policy they would come up with would give African nations pause.

[RandomGuy]

Well, I think the desert is the ideal place for such projects. The biggest problem is trying to send the electricity any large distance. Now I'm not in favor of the molten salt platforms. Yes, they have some great upsides, but the downside if the salts ever freeze in the piping...

A facility would need to be 1/2 gigawatt or larger in my view, and make use of a DC power line of 500 KV or more to be practical for any distance.

I would think that the salts "freezing" in the piping would be more than a bit remote, as I imagine they probably could, in a worst case scenario, simply burn fuel to keep them above temperature.

Even without this, they would have more than ample notice to clear the pipes well before that. The temperature would be monitored 24/7. It wouldn't be like it would sneak up on them, and they could simply start drawing out less heat to compensate when it got too low, again, in a worst case scenario.

I just don't see your concerns as being realistic at all, and I have a feeling that if I talked to an actual engineer on one of those projects, they would say as much.

Hell, it interests me, so I just might do that.

[RandomGuy]

For the solar collection, I don't know. That part could be several locations within a few hundred miles of the facility that would change it to high tension DC for long distance transport. My whole point is that without scaling large, the costs of long haul energy transport do not pay off. The higher the voltage, the less power you have due to restive losses. You cannot transmit AC power long distances either, because the power lines start to act as antennas and the power radiates out.

I've been inside the power facility in The Dalles, OR years ago that takes the power from nearby hydroelectric dams on the Columbia River and ships the power to Los Angeles. At the time, they used 30' tall mercury vapor rectifiers. Now they use solid state devices, and have increased their capacity to 2.1 giga-watts if I recall. My thoughts are this proven technology would be useful to collect energy from desert areas and ship as much as a thousand or two miles.

Morocco is less than a hundred from Spain.

If you look at a map, 2,000 miles would get from the northern coast of Africa to all of Europe.

Realistically, you just have to get it to the closest grid in Spain, Italy, or Greece, generally about 500-750 miles or so, and that is across the fairly shallow Mediterranean sea. Doesn't seem like too much of a technical hurdle.

[Wild Cobra]

Lol. Yeah i didn't think that was a realistic scenario. But what lengths would the EU go to to ensure uninterrupted power?

I think that any policy they would come up with would give African nations pause.
What ever happens, the backers would have to acknowledge that the land owners would eventually have the leverage.

[Wild Cobra]

I would think that the salts "freezing" in the piping would be more than a bit remote, as I imagine they probably could, in a worst case scenario, simply burn fuel to keep them above temperature.

Even without this, they would have more than ample notice to clear the pipes well before that. The temperature would be monitored 24/7. It wouldn't be like it would sneak up on them, and they could simply start drawing out less heat to compensate when it got too low, again, in a worst case scenario.

I just don't see your concerns as being realistic at all, and I have a feeling that if I talked to an actual engineer on one of those projects, they would say as much.

Hell, it interests me, so I just might do that.
Well, it gets complicated should the salts ever freeze up. The pipes are insulted as not to radiate heat. That means heating them is complicate as well. I assume someone could devise some system, but there is never 100% certainty, and as certainty increases, so does cost.

I cannot recall all the details, but what I have read in the past, I am left with the impression that if the salts ever freeze, the pipes have to be scrapped and rebuilt.

[boutons_deux]

liquid salt as an energy reservoir for solar thermal plants is stored on site, right next to the generator plant.

it is not piped long distances. WTF?

[Wild Cobra]

liquid salt as an energy reservoir for solar thermal plants is stored on site, right next to the generator plant.

it is not piped long distances. WTF?
You are right. If any part of the system freezes, it is a major problem though. I forget the temperature, but those salts used are solids at room temperature, and beyond. It takes some serious heat before they melt.

Maybe I'm wrong, but it is my opinion, but I think using such a method is more of a problem than the good they offer.

Keep in mind, I do not discount the efficiency of using them. I just fear the possible problems.

[boutons_deux]

do you really think solar thermal engineers don't know how insulate high temperature pipes? no matter what's in them? do you think liquid salt losing liquefaction has only occurred to you and not the engineers?

[boutons_deux]

Molten salt storage

A variety of fluids have been tested to transport the sun's heat, including water, air, oil, and sodium, but molten salt was selected[who?] as best.[citation needed] Molten salt is used in solar power tower systems because it is liquid at atmosphere pressure, it provides an efficient, low-cost medium in which to store thermal energy, its operating temperatures are compatible with today's high-pressure and high-temperature steam turbines, and it is non-flammable and nontoxic. In addition, molten salt is used in the chemical and metals industries as a heat-transport fluid, so experience with molten-salt systems exists in non-solar settings.
The molten salt is a mixture of 60 percent sodium nitrate and 40 percent potassium nitrate, commonly called saltpeter. New studies show that calcium nitrate could be included in the salts mixture to reduce costs and with technical benefits. The salt melts at 220 °C (430 °F) and is kept liquid at 290 °C (550 °F) in an insulated storage tank. The uniqueness of this solar system is in de-coupling the collection of solar energy from producing power, electricity can be generated in periods of inclement weather or even at night using the stored thermal energy in the hot salt tank. Normally tanks are well insulated and can store thermal energy for up to a week. As an example of their size, tanks that provide enough thermal storage to power a 100-megawatt turbine for four hours would be about 9 m (30 ft) tall and 24 m (80 ft) in diameter.
The Andasol power plant in Spain is the first commercial solar thermal power plant to utilize molten salt for heat storage and nighttime generation. It came online March 2009.[64] On July 4, 2011, a company in Spain celebrated an historic moment for the solar industry: Torresol’s 19.9 MW concentrating solar power plant became the first ever to generate uninterrupted electricity for 24 hours straight. It acheived this using a molten salt heat storage design.

http://en.wikipedia.org/wiki/Solar_thermal_energy#Molten_salt_storage

[coyotes_geek]

You are right. If any part of the system freezes, it is a major problem though. I forget the temperature, but those salts used are solids at room temperature, and beyond. It takes some serious heat before they melt.

Maybe I'm wrong, but it is my opinion, but I think using such a method is more of a problem than the good they offer.

Keep in mind, I do not discount the efficiency of using them. I just fear the possible problems.

Meh. It is a concern, but lord knows how many thousands of other process applications require a strict ability to control temperature. It's a concern, but it's not a big deal.

[Wild Cobra]

Molten salt storage

A variety of fluids have been tested to transport the sun's heat, including water, air, oil, and sodium, but molten salt was selected[who?] as best.[citation needed] Molten salt is used in solar power tower systems because it is liquid at atmosphere pressure, it provides an efficient, low-cost medium in which to store thermal energy, its operating temperatures are compatible with today's high-pressure and high-temperature steam turbines, and it is non-flammable and nontoxic. In addition, molten salt is used in the chemical and metals industries as a heat-transport fluid, so experience with molten-salt systems exists in non-solar settings.
The molten salt is a mixture of 60 percent sodium nitrate and 40 percent potassium nitrate, commonly called saltpeter. New studies show that calcium nitrate could be included in the salts mixture to reduce costs and with technical benefits. The salt melts at 220 °C (430 °F) and is kept liquid at 290 °C (550 °F) in an insulated storage tank. The uniqueness of this solar system is in de-coupling the collection of solar energy from producing power, electricity can be generated in periods of inclement weather or even at night using the stored thermal energy in the hot salt tank. Normally tanks are well insulated and can store thermal energy for up to a week. As an example of their size, tanks that provide enough thermal storage to power a 100-megawatt turbine for four hours would be about 9 m (30 ft) tall and 24 m (80 ft) in diameter.
The Andasol power plant in Spain is the first commercial solar thermal power plant to utilize molten salt for heat storage and nighttime generation. It came online March 2009.[64] On July 4, 2011, a company in Spain celebrated an historic moment for the solar industry: Torresol’s 19.9 MW concentrating solar power plant became the first ever to generate uninterrupted electricity for 24 hours straight. It acheived this using a molten salt heat storage design.

http://en.wikipedia.org/wiki/Solar_thermal_energy#Molten_salt_storage
Yes, I am aware of these facts. It is other experts in the field who fear the solidification of the salts. Not just me.

Look, I would be glad to find cause to say "I'm wrong." I just still think it's a valid concern.

[boutons_deux]

links that say pipes carrying a liquid at 550F can't be reliably insulated?

[Wild Cobra]

links that say pipes carrying a liquid at 550F can't reliably insulated?
Sorry, I don't have a photographic memory.

Do you?

[boutons_deux]

"do your own research"

[Wild Cobra]

"do your own research"
You expect me to research what I have already been exposed to, just so I can give you a link?

Do your own research![/QUOTE]

[Agloco]

How inefficient would it be to pipe molten salt hundreds of miles......across a body of water no less.

[Wild Cobra]

How inefficient would it be to pipe molten salt hundreds of miles......across a body of water no less.
Now that I think would be a financial nightmare. However, I haven't attempted to do the math. Just a gut feeling.

[Agloco]

Now that I think would be a financial nightmare. However, I haven't attempted to do the math. Just a gut feeling.

Well I think any design would necessarily put steam turbines near the molten salt reservoirs. They represent the most inefficient link in the chain, besides collection of course.

I'm just wondering why you and Boutons are going round and round about piping.

[Wild Cobra]

Well I think any design would necessarily put steam turbines near the molten salt reservoirs. They represent the most inefficient link in the chain, besides collection of course.

I'm just wondering why you and Boutons are going round and round about piping.
Yes, the two would need to be as close as practical. As for Boutons and myself... I will admit to some bias against him. I'm sure he is biased against me too.