Solar Panels...

[Tab]

Is this even feasible? I mean, I don't know much about solar technologly. How much would it cost to place solar panels all over the top of your average house? Is cost effective?

 

[Sunbird]

I've thought about having houses like that for years.

If every new house had to have it, then the cost of solar panels would decline a lot due to mass production, as well as money that could be allocated to solar R&D for improvements and new solar technologies would rise.

Also, it doesn't mean that the house doesn't need to be on the electrical grid, it can be on the grid for rainy/cloudy weeks and such. The big thing is it relieves much pressure on the grid, as well as reduces your electrical bill.

And for overnight usage, a lot of electricity could be stored in these newer and better batteries that are coming out. And the batteries would also not be so terribly expensive due to mass production

I wish it was so.

 

[Mark R]

There is a lot of energy that is potentially obtainable from solar. The problem is that current Photo-voltaic (electric solar panels) are not very good - poor efficiency, very high price, etc. Their life is limited too (25 - 30 years is generally regarded as the maximum).

In terms of cost, even somewhere like SoCal and with a government subsidy, solar electricity will cost you a lot more than electricity from the mains, except in very remote areas without an existing electricity supply. If you want to go 'off-grid' completely, then the price of batteries makes this even more expensive. For example, a 2000W solar system (no batteries) will generate about 4000 kWh per year in a sunny area, cost around around $15,000 and need about 200 sq feet of roof space - It will be able to deduct about $500 per year from your electricity bill. However, unless your power company provides 'net metering' you will not get that full $500 back, meaning the panels will never pay for themselves. If you have to refinance, or enlarge your mortgage to fit the panels, then the interest costs will make the project even more expensive.

My personal feeling is that if you want solar power, use solar water heating. Solar water heaters are much more efficient than PV panels (collecting up to 60% of the sun's energy, instead of 10%), much smaller and much cheaper. Water heating is a major energy consumer in the home, so a solar heater can be worthwhile. Even in Winter, you'll get useful heat, but you will probably need a normal burner to 'top-up'. A high performance 2000W water heater will probably cost around $5000 installed, and bring savings of $150-400 per year depending on how much water you use, and how you heated it before. However, like PV, this isn't always a clear winner financially.

 

[MobiusPizza]

Yeah, solar cells we human make are not yet as efficient as plants... A bit of a shame
The fuel cell technology advancement recently is quite promising. Using bio-modified cultures of algae to capture solar energy to break down hydrogen molecules from water to generate fuel that can be used for future cars and household fuel. Hydrogen fuel is the cleanest fuel known to man.

That might replace the expensive solar cells.

 

[vegetation]

The return on investment for solar electric panels is no where near optimal wherever one can plug into the grid, even in areas with high electric fees. Solar heaters, which operate differently, is quite decent for many family homes though. Personally save about $25-$30 a month on electricity by using solar water heating; the cost of install after incentives and rebates was less than $1500 so it's paid off quite well.

 

[DrPizza]

I've been entertaining various ideas to make my home more energy self-sufficient. One of these days, I'm going to get around to making some windmills to generate a bit of electricity (I couldn't care less about the return on investment... it's for the coolness/geek factor of building my own windmills; winding my own coils, etc.) I had thought about solar power, but realized that it'll pretty much mean I just buy something off the shelf - no point since the return on investment is so low. However, solar water heater... - Questions: in the NorthEast, with our cold winters, is this something that I'd just have operational about 1/2 to 3/4 of the year? Is this a manageable DIY type of project? - could I just run a lot of 1 inch CPVC (painted black) or other type of tubing on the roof, and tie it into the existing hot water system?

And, oddly, it just occured to me... could I air condition my house by running cold water through the hot-water baseboard? On second though... condensation would be a problem.

 

[Jeff7]

See the link in my sig, for one thing.

A nice little forum there, with all kinds of alternative energy stuff - wind and solar seem to dominate, with a little bit of hydro power ideas too.


But solar panels' main problem right now is cost. Putting up enough panels to power a house, plus either batteries, or a grid-tie inverter (expensive things) costs a helluva lot of money.

Originally posted by: AnnihilatorX
Yeah, solar cells we human make are not yet as efficient as plants... A bit of a shame
The fuel cell technology advancement recently is quite promising. Using bio-modified cultures of algae to capture solar energy to break down hydrogen molecules from water to generate fuel that can be used for future cars and household fuel. Hydrogen fuel is the cleanest fuel known to man.

That might replace the expensive solar cells.

Actually, plants are incredibly inefficient, somewhere around 1%. They really don't produce a lot of energy - however, think of how little energy they need. They just sit there all day, producing nutrients they need, relying on capilary action to provide water and circulation, and insects to do the hard work of reproduction.

And hydrogen can't replace solar cells - because plants are so inefficient, solar power could be used for electrolysis of water to get hydrogen. Hydrogen isn't a means of producing energy. It is merely a means of transporting it, just as gasoline is. Energy is bound up in the material - burning it releases that energy.

DrPizza - you especially would like the Otherpower.com forums. They've got a good number of people there with lots of home-built wind turbines. Pretty damn fine work too - they use neodymium iron boron magnets (ridiculously, and dangerously powerful), along with home-wound coils, salvaged bearing assemblies, and hand carved blades.

I bought a mess of solar cells off of a seller on eBay; I'm working on a good way of making my own panels. I'm wary of the methods used at the Otherpower site, as they just use tempered glass with foam tape, or silicone around the outside edges. This seems prone to leakage - and the glass that the big companies use has a few layers of plastic over it for additional protection.
I'm looking at using polycarbonate for the front - very durable stuff, and it can be treated for UV resistance. I want the panels I make to be around in a good number of years, and that means enduring sub-zero temps in the winter, high-heat in the summer, high winds, and hail. When I say high heat, these cells reach 60C just sitting indoors in the sun, at an ambient temperature of maybe 22C. Now imagine them at an ambient temperature of close to 40C (over 100F).

 

[MobiusPizza]

Originally posted by: Jeff7

Actually, plants are incredibly inefficient, somewhere around 1%. They really don't produce a lot of energy - however, think of how little energy they need. They just sit there all day, producing nutrients they need, relying on capilary action to provide water and circulation, and insects to do the hard work of reproduction.

And hydrogen can't replace solar cells - because plants are so inefficient, solar power could be used for electrolysis of water to get hydrogen. Hydrogen isn't a means of producing energy. It is merely a means of transporting it, just as gasoline is. Energy is bound up in the material - burning it releases that energy.

Yeah. But solar cells aren't a lot better.

Algae I mentioned earlier is a completely different story to plants. It's a very hot topic in hydrogen economy research because it is the most efficient way currently to directly break down water from energy from sunlight.

Hydrogen can generate electricity; It's what the intense research on hydrogen fuel cells are about. Also they are good fuel and since if you are generating it at home then you don't need to worry about transporting it.

The only reason hindering hydrogen economy development is actually the transportation of hydrogen. Although it's light, it cannot be liquified easily and transported in bulks.

 

[imported_Mitchell]

It's about $20k US to put solar panals on a roof to generate sufficient power to warrent the initial expense. Most people will not pay that fee when purchasing a new house.

 

[bsobel]

Originally posted by: Tabb
Is this even feasible? I mean, I don't know much about solar technologly. How much would it cost to place solar panels all over the top of your average house? Is cost effective?

Like electric cars your moving the problem elsewhere, not solving it. It currently takes more power to produce a solar cell than it will generate during it's usefull life (25-30 years). Further (as I mentioned in the P&N thread) the real problem we've yet to solve isn't genertation (not to say it's not important) it's storage... Those batteries are worse for the environment (same problem as the Pirus, great idea until you swap those batts ever 70k miles) than generating power from coal (unscrubbed)

Bill

 

[Calin]

Originally posted by: AnnihilatorX

Originally posted by: Jeff7

Actually, plants are incredibly inefficient, somewhere around 1%. They really don't produce a lot of energy - however, think of how little energy they need. They just sit there all day, producing nutrients they need, relying on capilary action to provide water and circulation, and insects to do the hard work of reproduction.

And hydrogen can't replace solar cells - because plants are so inefficient, solar power could be used for electrolysis of water to get hydrogen. Hydrogen isn't a means of producing energy. It is merely a means of transporting it, just as gasoline is. Energy is bound up in the material - burning it releases that energy.

Yeah. But solar cells aren't a lot better.

Algae I mentioned earlier is a completely different story to plants. It's a very hot topic in hydrogen economy research because it is the most efficient way currently to directly break down water from energy from sunlight.

Hydrogen can generate electricity; It's what the intense research on hydrogen fuel cells are about. Also they are good fuel and since if you are generating it at home then you don't need to worry about transporting it.

The only reason hindering hydrogen economy development is actually the transportation of hydrogen. Although it's light, it cannot be liquified easily and transported in bulks.

While hydrogen is good as fuel, you loose much during the storage part - assuming you use small tanks at high pressure (like 100 atm), you must compress it into the tank. However, when you recover it from the tank, you recover it at a much lower pressure (thru a pressure reduction device) so you could use it in low-pressure devices like car engines.
One model of hydrogen car made/showcased by Ford recently has an almost normal engine, uses some 200l of hydrogen storage tanks and is capable to go some 230km (150 miles) from a full load of hydrogen.
EDIT: the car used an internal combustion engine

 

[Calin]

Also, in cars you could fit a fuel tank everywhere (planes have fuel tanks in their wings). However, a high pressure tank must be cylindrical in shape (for the best resistance against internal pressure effects). This limits even more their utility in cars

 

[MobiusPizza]

Yeah storing and transporting hydrogen has so far always been the problem...

 

[bobsmith1492]

Also, don't forget many people live in places like good ol' Michigan here where we only get sunny days like three weeks out of the year.

Solar cells are crap in general.

 

[Sunbird]

Maybe for cloudy places we should invent cloud panels?

Anyway, there is much more radiation coming from the sun than just the visible spectrum and a lot of them can penetrate clouds, so do standard solar panels use these frequencies of light for energy creation too?

 

[bsobel]

Anyway, there is much more radiation coming from the sun than just the visible spectrum and a lot of them can penetrate clouds, so do standard solar panels use these frequencies of light for energy creation too?

Yes. It's just that the conversion just isn't there to do usefull work.

 

[Sunbird]

And another thing I thought of to store the collected energy from the panels, please tell me how feasable this is.

The solar panel drives a motor while it can, that winds up these springs (for lack of a better word) that could unwind at night to produce electricity for the lights or such. It like those wind up radios and torches.

I also suspect it would need such a massive amount off panels.

 

[jagec]

Originally posted by: AnnihilatorX

Originally posted by: Jeff7
Actually, plants are incredibly inefficient, somewhere around 1%.

Yeah. But solar cells aren't a lot better.

The maximum efficiency a solar cell made from a single material can achieve in converting light to electrical power is about 30 percent; the best efficiency actually achieved is about 25 percent. To do better, researchers and manufacturers stack different band gap materials in multijunction cells.

How is that not "a lot better"?

 

[bobsmith1492]

The problem is that the most efficient solar cells are made from gallium arsenide, which costs incredibly more than silicon and is why they are only used for satellites and the space station where weight matters more than cost. Normal silicon cells are a lot worse.

 

[Jeff7]

Originally posted by: bobsmith1492
The problem is that the most efficient solar cells are made from gallium arsenide, which costs incredibly more than silicon and is why they are only used for satellites and the space station where weight matters more than cost. Normal silicon cells are a lot worse.

Currently, silicon solar cells get somewhere around 13% efficiency, vs 25-30% for the gallium arsenide things.

 

[Colin1497]

My sr. design project was a solar powered aircraft. About 7 years ago the best cells we could get were 14% efficient, if my memory serves me correctly. This is generation of DC power, so for use in your house you're going to have to have an inverter.

For the planform area of our wing, we generated approximately the same power output as either 6 or 8 nicad batteries. Not impressive. Oh, and for weight reasons we used unpackaged cells but they were paper thin and broke all the time.

Anyway, solar is better used for heat, as someone said. Wind is a better renewable source of electricity. Nuclear would be great if they could resolve the waste storage issues and people wouldn't be so panicky about it. Europe does great with nuclear power...

 

[Jeff7]

Originally posted by: Colin1497
My sr. design project was a solar powered aircraft. About 7 years ago the best cells we could get were 14% efficient, if my memory serves me correctly. This is generation of DC power, so for use in your house you're going to have to have an inverter.

For the planform area of our wing, we generated approximately the same power output as either 6 or 8 nicad batteries. Not impressive. Oh, and for weight reasons we used unpackaged cells but they were paper thin and broke all the time.

Anyway, solar is better used for heat, as someone said. Wind is a better renewable source of electricity. Nuclear would be great if they could resolve the waste storage issues and people wouldn't be so panicky about it. Europe does great with nuclear power...

Maybe once we figure out how to build space elevators, using solar-powered orbital platforms as bases, we can send nuclear waste into space that way (no air pollution of rockets), and use ion engines, or else just a small conventional engine, and send the stuff into the sun. Of course, by that time, we might have finally made a nuclear fusion reactor that provides a positive net energy output.

 

[DrPizza]

Originally posted by: bsobel

Originally posted by: Tabb
Is this even feasible? I mean, I don't know much about solar technologly. How much would it cost to place solar panels all over the top of your average house? Is cost effective?

Like electric cars your moving the problem elsewhere, not solving it. It currently takes more power to produce a solar cell than it will generate during it's usefull life (25-30 years). Further (as I mentioned in the P&N thread) the real problem we've yet to solve isn't genertation (not to say it's not important) it's storage... Those batteries are worse for the environment (same problem as the Pirus, great idea until you swap those batts ever 70k miles) than generating power from coal (unscrubbed)

Bill

I'm curious now about how much energy it does take to produce a solar cell. Anyone have any stats from a reliable source? I've been discussing this with students in my physics class and how they really need to take a broader look at changes before deciding if they truly are beneficial. (i.e. after they told me that hydrogen cars produce no pollution, I asked them to find out how the hydrogen is produced) Up to this point, I was fairly convinced that solar, wind, and fusion were the best for the environment (if we ever get fusion to a point where it's feasible.)

 

[kakarotxiv]

if everyone had them we'd be free of utilities

 

[Fricardo]

The Department of Energy did a study on various types of renewable energy production and their economic viability. Solar panels are, as many have stated, very inneficient. On top of being inherently inneficient, they produce DC power wich has to be converted to AC at about a 50% loss if you want to distribute it. The most efficient method the study found was sterling engines.

Sterling engines produce mechanical motion from heat differentials. The implementation discussed would use collecting dishes to concentrate solar energy on these devices. Even current sterling engine tech is about 30% efficient -- and they produce AC current that doesn't need to be converted for distribution. If a reasonably-sized farm of these were produced, the study concluded, prices for power would be around 12cents/kWH, which is near the top of end of what current production is during peak times; and that's exactly when the engines would be producing the most energy.

This seems to me to be the most viable solution to the ever-present problem of "where does the energy actually come from?" when talking about a hydrogen economy. I don't know why the government doesn't get us started on this sort of thing right now.