PV Gap

Charlene Said:

I may have found a basic flaw in solar energy. Any thoughts?

We Answered:

I salute your accomplishment; not many have had the patience and persistence to build up their own panel from individual cells. You would make a good counterpoint to those sites like earth4energy that imply one can build a panel for less than $200 and power the entire house with it.

If I'm reading right, you're getting maybe 2 to 2.5 watts from your setup. The max power point may be somewhere in between those two voltages you measured, but that's a technical discussion for another time.

The cost, if £1 = $1.50, was $450. For a little less than $350, you can get the 120-watt panel here http://sunelec.com/index.php?main_page=p… . For a residential install, you would typically get larger panels, possibly at a better price per watt.

Your estimate of £1000's for a rooftop system is right, but for that kind of money, our array managed to supply our entire electrical needs (6500 kWh/yr), including an electric stove and oven, washer/dryer, refrigerator, and other appliances. We have no air conditioning, and heat is from natural gas, including the dryer. And we're in California, possibly a sunnier location than you. We paid $12k net, but the same system today would be more like $10k.

Amy Said:

Why are we being conned on climate change?

We Answered:

This little bunnywabbit says that you have asked a question and then answered it with your opinion, therefore it is not a question but a statement of your opinion. This little bunnywabbit thinks that your opinion is very naive. You talk only of profit for utility companies. The potential profits from companies developing and supplying non carbon energy are light years ahead of the old carbon industries and therefore mean much more tax for govt. Governments are ;putting billions into developing new energies. That says your comments are based on a total lack of knowledge. Problem with china is they cannot afford to wait so they build coal fired power stations. That does not increase tax for governments in the rest of the world, does it? So what does your comment about china have to do with it?

Where I live the government gives grants to people to reduce carbon emissions in their homes, ie reduce consumption of uitity company product, how does that help to improve profit of utilities and therefore tax? The Govt loses money giving the grants and loses money because people use less fuel. Your added info proves my point. You did not ask a question, you tried to impose your naive view. You just further added impetus to your opinion. SO WHAT ACTUALLY WAS YOUR ORIGINAL QUESTION? You ask a question for other opinions, you do not ask a question to dictate the answer to everybody else. Get it now?

Ignorance is bliss, so they say

Gwendolyn Said:

How to get a 100% efficient Light Source with Brilliance?

We Answered:

What is your question again? I mean, I appreciate the information, but what is it that you want to know? It seems that you are comparing apples and oranges.

The closes to 100 percent efficient source is an LED, which produces a photon per electron injected in the junction. There is, however, the problem of light extraction due to total internal reflection in the semiconductor itself. This is, light is produced with almost 100 efficiency, but only some fraction of that would make it out of the semiconductor.

I used to do research on that during my PhD and we proposed a method to extract light in a more efficient manner, but we didn't come anywhere near close to 100 percent extraction. Maximum was, I think, about 50% extraction.

Hilda Said:

please rate my essay for TOEFL... out of 6.0?

We Answered:

5.5
very good- already know there is much time put in this essay.
very good.
Try adding one more paragraph

Paula Said:

which kind of solar panel is better ? made of polycrystiline cell or monocrysteline cells?

We Answered:

Hey Robin, Roderick is exactly right. The only difference in using a polycrystaline versus a monocrystaline panel is the mono panel is slightly more efficient. That translates into making a little more power per square foot of panel space. In the end you pay a slight amount more for the mono panel, but in most applications, power output per square foot is not a factor. We power our entire home from a solar array, it fits in less space than the roof of our one car carport, so there is no need to make it fit in a slightly smaller space. Mono panels were the first ones built in the 60's for the space program. Multicrystal panels came later at a slightly lower cost. Both types work fine, both are guarenteed to run for 25 plus years, and since you are paying a price per watt rather than a price per square foot, it doesn't matter from the user end which type you use.

In our case, we actuallly selected the multi crystal panels for looks, the crystal like blue hue of the panel worked better on our home aesthetically than the bullet point look of the single crystal panels. If you're putting a large array on your home, it is something to think about. There is a really good magazine devoted entirely to home made energy, with lots of ads and articles about solar. You can get it online, I will list it below. Good luck, and take care, Rudydooo