Solar Electricity

[Massacure]

PV cells are expensive and ineffecient. So I thought of an idea. You know how some people sell solar ovens? Well if they cook food, they must be able to turn water into steam. So what if I were to make a bunch of solar ovens and put tubing in them to hold water. Then I connect the tubes up to a steam generator, or perhaps a sterling engine. Would this prove to be more economical than PV panels?

Can anyone give me information or comments on this?

[Kellanved]

1. look here

Solar thermic Power Plants are quite effective.
http://www.nrel.gov/docs/fy01osti/28751.pdf

[mike_c]

2. this approach has been around for a long time...

...but I don't know whether any of the existing mirror arrays are used for commercial generation.

Let' see, Google "solar electricity steam"-- yep, 101,000 hits-- here's one from Arizona Solar: http://www.azsolarcenter.com/technology/electric.html

[Ironpost]

3. we have to start somewhere

in the mid '70s there was an installation north of warner springs California, that had several acres of mirrors focused on a tower that at the top had a steam generator. To long ago to remember much about it but more than likely I read about it in popular science or mechanic illustrated. that might be a good place to start. Just a thought. I was stationed at S.E.R.E base north of warner springs in the late '60s That is why it had caught my attention then. Good luck.

[Trillo]

4. Here's another site for ideas

http://www.canren.gc.ca/tech_appl/index.asp?CaID=5&PgID=282
Check the parabolic trough system.

I think that if the tube running along the focal point of a parabolic mirror is a dual-tube with a vacuum in between, they're highly efficient. A few years back some university got a patent on the dual-tube vacuum, if memory serves me.

I've heard of a liquid other than water being used that has a high boiling temperature, in systems like the above, then that liquid can be circulated into a heat exchanger for generating high-pressure steam, which then drives a turbine for electricity production.

There's really no reason other than cost that a small system with a micro turbine couldn't be made, but it would only generate electricity while the sun is in the sky. There are natural gas powered micro turbines available as stand alone power plants, generating I believe 30 kwh. I can't remember the name of the company. There's really no reason that the micro-turbine couldn't be steam driven.

But how do you solve the energy storage problem for nightime electricity, without resorting to batteries which have their own enviornmental problems?

Aside from the cost, I really like the idea of grid tie solar cell systems for rooftop mounting on homes, but when I looked into the cost of a system 4 years ago, one that would feed a net surplus of energy back to the electric company, averaged over the course of a whole year, the cost was 60K before any credits available were applied. Because there are no moving parts, it seems like they'd be relatively reliable, unlike a microtubine might be.

[salvorhardin]

5. Solar cells do wear out after a whle too...

I think the current lifetime is about 20 years and then you have to dispose of the old ones and install new.

[Trillo]

6. Back in the 80s or 90s,

Back in the 80s or 90s, there was a TV show (not a whole show, just a few minutes) about a fantastic new process using a laser that created solar cells extremely inexpensively compared to the prior processes. Cost estimates at the time were a few cents per square foot.

With all the rest of corporate corruption that we're seeing today and anti-competitive actions routine, it is easy to suppose that the high cost of solar cells today has more to do with corporate profit than cost of production.

[Massacure]

7. The cost is largly at the mercy of silicon prices

Doesn't silicon have to be specially manufactured to high specifications in vaccum chambers?

[Trillo]

8. Isn't silicon just processed sand? n/t