Solar Power

[Rainsford]

Originally posted by: charrison

Originally posted by: Dissipate

Originally posted by: Rainsford
I think solar power has huge potential, especially as more research is put into the materials that go into the panels. Solar power collection is really just starting out, despite having been around for a while, we're really only starting to jump in with both feet. While doing it at the individual building level is fine, I wonder about doing large scale "solar power plants". I suppose there isn't a whole lot of difference, but large scale could take advantage of better locations (suppose your house is surrounded by tall trees) and better technology. And given the ability to transfer power all over the place, we could really take advantage of geographic areas that have a lot of sunshine all year round.

I believe the large scale solar power plants use parabolic mirrors that focus the sun's rays which creates a a lot of heat which powers a steam generator. Hence, no solar panels.

Actually they have both.

Yeah, I had heard of the steam and mirror ones, I was thinking more along the lines of solar panels. But I suppose, whatever works.

 

[Paratus]

Whether you use panels or reflectors you are still limited to max solar energy incident on the planet. About 330W/m^2.

posted via Palm Life Drive

 

[Rainsford]

Originally posted by: Paratus
I just thought I would add my two sense here.

Solar power as a primary power source sucks. I know this as I operate the largest solar arrays ever flown in space (ISS)

The main problems are storage and pointing. Even with advanced nickel hydrogen batteries we only have about 3-5 hours of power if power generation fails. Plus power falls off with the cosine with the angle to the sun so as your pointing gets worse so does your power. That plus hardware limitations means that while I can generate 60 KW I can only use about 24 to power users loads. The rest is used to recharge the batteries or is lost due to inefficiencies.


That being said mounting solar panels to houses is the perfect way to add solar power to this nations power grid.

I'd lov to see some govt tax breaks to that effect.

I don't think people are really viewing it as a primary source of power, if only because of the battery issue. Even without everything else you said, batteries just aren't good enough today to make it worthwhile to store enough power. However, as a secondary source solar power is great. When it works, you get "free" power. When there are dips in solar power output, you simply use the primary source.

 

[Paratus]

Exactly my thoughts as well.

 

[charrison]

Originally posted by: Paratus
Whether you use panels or reflectors you are still limited to max solar energy incident on the planet. About 330W/m^2.

posted via Palm Life Drive

There is enough power hitting roofs to power the house beneth them, most of the time.

 

[judasmachine]

one small benefit to a metal/solar panel roof is that you are not using shingles which are usually made in part from petroleum. it's not a great thing but still nice.

Here is a local anecdote from a Texas paper. It's an interesting read.

 

[Zebo]

Originally posted by: Meuge
I was pricing them for my parents' house and they come out to about $8000 altogether, including installation. However, they would pay for themselves in only a few years (5-7). The bigger problem for me was the fact that the waiting lists for good panels reach into the late 2008.

How much power will that generate? What about Batteries? Inverter?

Not to mention $8000 buys a heck of a lot of months of power bills. $8000 @ 10% intrest would pay many peoples power and never use the principle. But I still think your way too low cost and way too low watts. I priced out a system about three years ago and it was $55,000. Assuming a 50% reduction incost as you indicate and its still $27,500.

Also you know youhave to replace the batteries every 5-7 years depending on temp right?

 

[Lizardman]

http://www.sba.gov/sbir/tibbetts/astropower.html

used to be located abouto 10min from my house, until it went under.

 

[zephyrprime]

Originally posted by: Paratus
Whether you use panels or reflectors you are still limited to max solar energy incident on the planet. About 330W/m^2.

posted via Palm Life Drive

That's more like 100 watts/m^2
http://solardat.uoregon.edu/SolarRadiationBasics.html

More on solar panel shortage. It is being driven by goverment subsidy all over the world and for the first time is using more silicon that semiconductors.

Solar panels are semiconductors too. I think the article actually meant that solar panels are using more silicon than ICs but such inaccuracies are what happens when regular reporters write technical articles.

 

[Meuge]

Originally posted by: Zebo

Originally posted by: Meuge
I was pricing them for my parents' house and they come out to about $8000 altogether, including installation. However, they would pay for themselves in only a few years (5-7). The bigger problem for me was the fact that the waiting lists for good panels reach into the late 2008.

How much power will that generate? What about Batteries? Inverter?

Not to mention $8000 buys a heck of a lot of months of power bills. $8000 @ 10% intrest would pay many peoples power and never use the principle. But I still think your way too low cost and way too low watts. I priced out a system about three years ago and it was $55,000. Assuming a 50% reduction incost as you indicate and its still $27,500.

Also you know youhave to replace the batteries every 5-7 years depending on temp right?

What batteries? Just put the current out of the inverter into the grid. I have no intention of storing electricity.

 

[rahvin]

Noone even questioned your first post so I will. Meuge, Show me a single solar panel available for residential installation that gets better than 25% efficiency. That 50% efficiency was just a bullsh!t number.

You MIGHT be able to get a solar equipment for the prices you have been quoted but if you want it installed properly then you need a professional install (you don't want to fvck around when putting stuff on the roof of your home) and there is no way you can legally tie a solar installation into your electrical system without a qualified electrition doing it. Keep in mind that if you do this without a building permit and proper inspection you will void your insurance. And I haven't seen a professional install quote for less than $15,000 for a decently sized system and you really need $25K to get a system size that's worthwile. Until panel prices come down it's not worth bothering with it.

 

[1prophet]

Sometimes what is best for the environment and our energy independence is not what is best for our wallet. Sometimes sacrifices need to be made even though our accountants will tell us it doesn't make financial sense.

 

[Hayabusa Rider]

A question I havent been able to find the answer to is what is the energy cost to produce the panels compared to what you get out of them.

Anyone know?

 

[cliftonite]

Originally posted by: rahvin
Noone even questioned your first post so I will. Meuge, Show me a single solar panel available for residential installation that gets better than 25% efficiency. That 50% efficiency was just a bullsh!t number.

You MIGHT be able to get a solar equipment for the prices you have been quoted but if you want it installed properly then you need a professional install (you don't want to fvck around when putting stuff on the roof of your home) and there is no way you can legally tie a solar installation into your electrical system without a qualified electrition doing it. Keep in mind that if you do this without a building permit and proper inspection you will void your insurance. And I haven't seen a professional install quote for less than $15,000 for a decently sized system and you really need $25K to get a system size that's worthwile. Until panel prices come down it's not worth bothering with it.

Maybe he was talking about the price after subsidies? I believe NY subsidizes solar installations.

 

[rahvin]

Originally posted by: Hayabusa Rider
A question I havent been able to find the answer to is what is the energy cost to produce the panels compared to what you get out of them.

Anyone know?

On a general basis panels produce the energy that was required to make them in less than 3 years. They are warrantied for 25 years and often last much longer than that before the circuits burn out.

 

[Engineer]

Solar spray on cells...FTW!

 

[mect]

Originally posted by: Engineer
Solar spray on cells...FTW!

Yes, now if those can just get up past 8% efficiency, we'll be in good shape. Here's the deal.

Organic materials (Cheap Price Low Efficiency): Cheap and easily processed because no expensive deposition processes are needed. Problems are efficiency and lifetime, as organic polymers tend to photodegrade and have very low electrical mobilities and only absorb a percentage of the solar spectrum. Blends of nanoparticles and polymers are being considered to extend absorption ranges and prevent electron hole recombination.

Single Junction semiconductors (Mid Price Mid efficiency): I believe these are approaching about 25% efficiency, which does give hopes for the organics, since traditional semiconductors started out where organics are today. If organic cells can reach the efficiency of current single junction semiconductor cells, we'll be in good shape.

Multijunction Semiconductors (High Price High Efficiency): These are layered cells with the top layer being transparent to lower energy light and each layer the band gap of the semiconductor decreases to absorb lower energy light. With a single junction cell, light is absorbed if it is of higher energy than the band gap and transmitted if it is of lower energy. The problem is that all energy absorbed will only produce electrical energy equal to the band gap. If you have a really high band gap material, the high energy photons give lots of energy but a large section of the visible light just passes through. If you use a small gap, you absorb a lot but a lot of the energy is lost to relaxation processes. The solar cells that are approaching 50% efficiency are these multijunction cells which are essentially a bunch of solar cells stacked on each other. So they are basically the price of say 3 normal solar cells.

There are some others as well, but these are the main ones that seem to get publicity (and that I've seen mentioned in this thread).

 

[MCsommerreid]

Solar cells for auxilary and alternative home power are still kind of things of the future. I'm all about solar water heating, especially in large houses. If the system is large enough it could probably replace both the water heater as well as the forced air/boiler heating systems of homes.

 

[MadRat]

I think the wind is the better alternative. When they get useful (1-1.5kW) windmills down to $1500 (just for the windmill not the inverter and batteries) then I'm in.

 

[BrownTown]

windmills are a good idea, but they can onyl provide a relatively small amount of power since there are onyl a few places there is enough wind to make them worthwhile. Also, enviromentalists don't like them, but thats becasue enviromentalists are stupid and want us to live in the stone age (OK, maybe not all of them, but honestly, extreme enviromentalists are insane).

 

[rahvin]

Originally posted by: mect
Single Junction semiconductors (Mid Price Mid efficiency): I believe these are approaching about 25% efficiency, which does give hopes for the organics, since traditional semiconductors started out where organics are today. If organic cells can reach the efficiency of current single junction semiconductor cells, we'll be in good shape.

Multijunction Semiconductors (High Price High Efficiency): These are layered cells with the top layer being transparent to lower energy light and each layer the band gap of the semiconductor decreases to absorb lower energy light. With a single junction cell, light is absorbed if it is of higher energy than the band gap and transmitted if it is of lower energy. The problem is that all energy absorbed will only produce electrical energy equal to the band gap. If you have a really high band gap material, the high energy photons give lots of energy but a large section of the visible light just passes through. If you use a small gap, you absorb a lot but a lot of the energy is lost to relaxation processes. The solar cells that are approaching 50% efficiency are these multijunction cells which are essentially a bunch of solar cells stacked on each other. So they are basically the price of say 3 normal solar cells.

There are some others as well, but these are the main ones that seem to get publicity (and that I've seen mentioned in this thread).

Those effeciencies are not anything but labratory and I question the approaching 50% of the multi-layers, it would be correct if by approaching you mean 35%. Take it from the lab to production and the highest you will find is ~28% for a single silicon crystal cell, about 15% for multicrystal cells and less than 10% for anything else.

 

[mect]

Originally posted by: rahvin

Originally posted by: mect
Single Junction semiconductors (Mid Price Mid efficiency): I believe these are approaching about 25% efficiency, which does give hopes for the organics, since traditional semiconductors started out where organics are today. If organic cells can reach the efficiency of current single junction semiconductor cells, we'll be in good shape.

Multijunction Semiconductors (High Price High Efficiency): These are layered cells with the top layer being transparent to lower energy light and each layer the band gap of the semiconductor decreases to absorb lower energy light. With a single junction cell, light is absorbed if it is of higher energy than the band gap and transmitted if it is of lower energy. The problem is that all energy absorbed will only produce electrical energy equal to the band gap. If you have a really high band gap material, the high energy photons give lots of energy but a large section of the visible light just passes through. If you use a small gap, you absorb a lot but a lot of the energy is lost to relaxation processes. The solar cells that are approaching 50% efficiency are these multijunction cells which are essentially a bunch of solar cells stacked on each other. So they are basically the price of say 3 normal solar cells.

There are some others as well, but these are the main ones that seem to get publicity (and that I've seen mentioned in this thread).

Those effeciencies are not anything but labratory and I question the approaching 50% of the multi-layers, it would be correct if by approaching you mean 35%. Take it from the lab to production and the highest you will find is ~28% for a single silicon crystal cell, about 15% for multicrystal cells and less than 10% for anything else.

I absolutely agree with you. Except that single crystal silicon won't come anywhere near 28%. They have to use a lot more complicated techniques with polycrystaline silicon to approach anything like that.

 

[MadRat]

Originally posted by: BrownTown
windmills are a good idea, but they can onyl provide a relatively small amount of power since there are onyl a few places there is enough wind to make them worthwhile. Also, enviromentalists don't like them, but thats becasue enviromentalists are stupid and want us to live in the stone age (OK, maybe not all of them, but honestly, extreme enviromentalists are insane).

Well, actually a good chunk of the U.S. is in moderately good places for wind. What is nice is that wind is most prevalent when the solar energy is not, during nights and inclement weather. Wind acts as a good filler alternative energy source.

 

[MCsommerreid]

Or wind could be used as an augment to solar, providing energy coverage where solar wouldn't work. Add geothermal and hydroelectric and all you need to do is use nuclear for areas that have massive power draws.

 

[Meuge]

Originally posted by: MadRat
I think the wind is the better alternative. When they get useful (1-1.5kW) windmills down to $1500 (just for the windmill not the inverter and batteries) then I'm in.

They are really huge and ugly though. The great thing about roof solar panels is that they're totally unobtrusive.