[Smertrios]

What are some ways of storing "sun energy" that would be useful for power generation? Below are a few of the things I have read about.

Store the heat to keep the steam turbines going 24/7? Needing at least 4x the number of solar collectors to store enough energy to power the turbines for the 18+ non-solar hours? How is "heat" stored and then used?

Store the power being generated in batteries? This is awful expensive unless large scale battery cost is cheap or custom batteries can be made cheaply. Can you imagine the cost of a battery bank capable of storing 250,000 watt hours of power? How can large capacity batteries be made cheaply?

Convert the energy to compressed gas and use that compressed gas during the non-solar hours to run a pneumatic motor? Large air tanks at high pressure are scary IMO not to mention expensive. Can the tanks be made cheaply or large enough so that lower pressures can be stored?

[NC Cams]

If you can find the answers to these questions, you'll be at the forefront of the break thru in solar power conversion.

WHy do you think that solar power has not taken off like oil based power sources? Simply a Lack of development and lack of AFFORDABLE power conversion/storage potential

All these tree huggers and politicians look at solar energy conversion as some sort of panacea. It is and always has been a difficult power source to store and convert to useable WITH THE KNOWN SORAGE and CONVERSION DEVICES

THis is not so say that it can't be done, I"m just saying that none of the methods used so far are as cheap or effective or efficient as the inefficient fuel power energy conversion devices we use now.

It is funny that you mention this sort of thing. I had a similar question asked on/in a mechanical engineering final exam I had nearly 40 years ago. The more things change, the more some things stay the same - sp,e [rpgress jas beem ,ade bit mpt empigjt tp compete with $5 or even #100 per barrel crude..

[ger21]

http://www.sandia.gov/Renewable_Ener...NSTTF/salt.htm

[skippy]

I was reading the other day about a wind turbine system (of the large wind farm project type) that will drive an integrated compressor during periods of excess wind. The compressed air is stored in huge batteries of underground receivers and used to drive pneumatic motors which in turn drive the generators to make electricity during periods of lower then expected wind or periods of high electricity demand which of course rarely coincides with high winds. Sounds like a good, even if super-expensive idea however I wouldn't be at all surprised if it was just another one one of those: Press Release: We've developed blablabla... Investor: "Oh wow, that's going to be a hit, time to buy" so they do and those in the know who invested prior to the press release make a killing, device turns out to be all just "hot air" (excuse the punn) and the press release did exactly what it was supposed to do. Make a ton of money for a handfull of people. Gee, don't I sound cynical?

[Geof]

Gerry's link describes a storage system that I think has great potential except for a fatal flaw; if it is scaled up to become a significant part of the electric supply there will not be enough saltpeter available.

I think this same flaw exists for nearly all the proposed solar energy storage systems, there will not be enough of the raw materials available to scale them up to a significant level.

There is really only one solar energy storage system for which the raw material is in adequate supply and that is rain. However, even this one is limited because to be useful the rain has to fall on the top of high ground in a location where a dam can be built and this combination of weather and geography is in short supply.

P.S. Nitrates are also fertilizers so this salt solution storage idea has some similarities to bio-fuels in that it would probably have a serious effect on food crops if implemented on a large scale.


Skippy; There are two ways to pronounce *c*y*n*i*c*a*l*; one is "cynical", the other is "realistic".

[mactec54]

Hi smertrios

You don't need to store the power you get from your solar cell you feed it back into the grid through a inverter it cuts your power bill down quite a bit like almost half if you have at least 3 good size cells also the water heating can be done with a solar water cell for further reduced power used

You can use the solar power also to charge your batteries in your electric/hybrid car
nothing is free but they pay you back in time

[martinw]

Dear Smertrios,

Your question "What are some ways of storing "sun energy" that would be useful for power generation?", has a dead cert. proven answer, but you may have to take a longer term view than you were considering.

Plant a few trees and wait. Photosynthesis will do the rest. Then after a few years you will have a good supply of logs to stuff into your local power plant. Of course, if you have more patience, you might eventually end up with some coal.

It might work..

Best wishes,

Martin

[Geof]

.....Plant a few trees and wait. Photosynthesis will do the rest. Then after a few years you will have a good supply....

I like your concept of "few years"'

Can I borrow a "few" pounds from you?

I promise I will pay you back in a "few" years (If you still exist).

[martinw]

I like your concept of "few years"'

Can I borrow a "few" pounds from you?

Dear Geof,

There seems to have been a bit of a misunderstanding about the direction in which funds might be moving.

I was actually thinking that you might like to buy some stock in my coal mine.

Best wishes,

Martin

[Switcher]

I know this is off topic (sun energy).

I think the best source of Alternate Energy is in ocean waves. Waves will never stop day or night, winter or summer!

The best design I have found is a Buoy, think of one of those cheap flashlights that you shake, that don't use batteries, the bouy is anchored to the ocen floor with a cable & bobs on top of the waves, I watched a youtube video of one a while back, very simple in design, no pollution, no need to store the energy in batteries, etc,...

It's funny how folks can't see the energy, cause the waves are in the way (what a waste).

BTW, I'm no tree hugger (I drive a Jeep Cherokee)



Links:

http://en.wikipedia.org/wiki/Wave_power

http://www.youtube.com/results?searc...rch_type=&aq=f

http://www.youtube.com/results?searc...rch_type=&aq=f


.

[Geof]

I know this is off topic (sun energy). ...

Not off topic; wave energy is merely stored solar energy, inefficiently stored at that. Uneven solar heating of the Earth's surface and atmosphere, combined with the Earth's rotation creates wind; wind generates waves. I think it is less efficient than rain and suffers from the same problems, the need for a fortuitous combination of weather and geography.

[Switcher]

I disagree,

We will have waves all day/night 24/7 tomorrow, that I will put my money on

Will it be sunny or windy all day/night tomorrow (who knows)?

I think it is less efficient than rain and suffers from the same problems, the need for a fortuitous combination of weather and geography

Still disagree,

I vacation/live on the South Carolina coast, the waves look just as large to me, windy or not.

************************************************** *

As far as geography, how far can a coal or nuclear power plant send energy down power lines?


.

[Geof]

I disagree,

We will have waves all day/night 24/7 tomorrow, that I will put my money on

Will it be sunny or windy all day/night tomorrow (who knows)?





Still disagree,

I vacation/live on the South Carolina coast, the waves look just as large to me, windy or not.

************************************************** *

As far as geography, how far can a coal or nuclear power plant send energy down power lines?


.

I was not comparing with wind, photovoltaic solar or nuclear, I was comparing hydroelectric solar energy, aka known as rain being trapped in dams, with wave energy. I would be surprised if more energy can be extracted from waves on a global scale than from rain and at lower cost.

[martinw]

Dear Switcher,

Ah, saltwater, that is the problem with most wave energy concepts.

Anybody who owns a small boat, a supertanker, a timber or RC dock, an oil rig or anything else that is dunked into the sea at the mercy of the waves knows that very few pieces of kit last very long. A few decades if you are very lucky.

I read somewhere , a long time ago, about the idea of using blow-holes at the foot of sea cliffs. The general idea is that the waves compress the air in the "cave" at sea level which then runs an air turbine higher up, and in no contact with salt water.

Is this a crazy idea that has no prospect of doing anything useful? If so, it will join a whole bunch of other bonkers ideas being proposed by the AGW industry.

Best wishes,

Martin

[Switcher]

A few decades if you are very lucky.

That's not bad IMO, make em modular, replace when needed.

This link is more of the idea I am thinking of http://eecs.oregonstate.edu/wesrf/ , I think they have ran it at 10kW so far.

So it is being done, just needs to be on a larger scale.

http://eecs.oregonstate.edu/wesrf/pr...-nonumbers.jpg


.

[Geof]

...This link is more of the idea I am thinking of http://eecs.oregonstate.edu/wesrf/ , I think they have ran it at 10kW so far.

So it is being done, just needs to be on a larger scale.

http://eecs.oregonstate.edu/wesrf/pr...-nonumbers.jpg


.

Awe come on. If you think this sort of stuff has commercial viability I can probably show you a bridge for sale In Brooklyn or a bunch of desert property in Florida.

[Switcher]

Awe come on. If you think this sort of stuff has commercial viability I can probably show you a bridge for sale In Brooklyn or a bunch of desert property in Florida.

Nice attitude. (nuts)

[Smertrios]

http://www.sandia.gov/Renewable_Ener...NSTTF/salt.htm

This looks like a good system but as was mentioned previously that is alot of melted $salt$. Any reason why the heat could not be stored in insulated containers filled with a solid like sand, rock, concrete or even dirt using the liquid salt to fill in the air pockets? Heat exchangers would be key!

[Geof]

....Heat exchangers would be key!

Yes the heat exchange would be important. Using something solid as you suggest puts two more heat exchange processes in the sequence and would reduce the efficiency. In addition rocks and sand, like most solids have a low heat capacity so you would need a much larger volume and it would need to be insulated.

[ImanCarrot]

or anything else that is dunked into the sea at the mercy of the waves knows that very few pieces of kit last very long

Sharks seem to have lasted a wee while. Even outlasted the dinosaurs by all accounts.

You're gonna say "yea, but sharks aint a bit of kit", but would you say that to one face to face? lol

All joking aside, what we should do is make big mirrors (concave) and stick them right near the sun to reflect the incident light and solar radiation back to a focus coincident with the sun's approximate centre. This will cause the sun to go nova (which it wouldn't normaly do) and create a lot of energy and a rather nice firework display...

*checks his notes for any flaws in the above hypothesis*... nope! seems ok to me!