Hi,
Is there anyone that has worked with this solar cells/panels? What I´m really looking for is general info, like, which ones are the best? Price? Main suppliers?
Thanks,
Hi,
I can’t give you any information on brands, but here’s what I know from my research. (I’m currently developing technology that is related to solar power.)
Most solar cells achieve only about 10-15% efficiency, because they use only a very limited band of the solar spectrum. The newest developments in solar cells is the advanced “multi-junction” photovoltaic. These latest cells, developed at Spectralab and Boeing, achieve a world record for photo-voltaics: 40.7%. This is done by utilizing much more of the sun’s spectrum to generate power, however, this involves custom layering, and makes the photovoltaic material much more difficult to build, and consequently, more expensive. The expense, however, is offset by the fact that part of the efficiency comes from using the photovoltaic material with sunlight concentrators (either lenses or mirrors), so very little of the material is actually used in a typical deployed panel.
Photovoltaics in general benefit from concentrating the sunlight up to 500-700 times, depending on where you are. Anything more will usually overheat the PV (photovoltaic) material, and anything less doesn’t use the material to its full potential. The one additional complicating factor in this is that with solar concentrators, the panels must be aimed at the sun so the mirrors or lenses will focus on the panels. Aiming a panel with sun tracking dramatically boosts the output of the panel when normal panels don’t have very high output, namely, in the morning, and in the late afternoon.
This latest development was just announced a few weeks ago. The vast majority of panels out there are not efficient enough to make them really worth the money if you take away subsidies; the currently market-available PVs take about 15-20 years to save you enough money to pay for themselves, which is not competitive enough to be compelling. However, the new multi-junction panels may end up tipping the balance of power; if they are not prohibitively expensive (or use more energy to produce than they are worth) solar power may end up becoming popular for good.
To give you an idea of just how much energy the sun puts out upon the surface of the earth, in 1995, the September issue of Scientific American had an article (author: Hoagland) that says this:
Every year the earth’s surface receives about 10 times as much energy from sunlight as is contained in all the known reserves of coal, oil, natural gas, and uranium combined. This energy equals 15,000 times the world’s annual consumption by humans.
If we could tap even 1% of that, it would be 150 times the world’s annual consumption by humans. Think about that. The future of energy must be solar; if only we would expend as much effort pursuing this free and clean source of power as we spend on exploring for oil, we’d probably be far more energy independent than we are now.
~Berkana
I have heard the same solar to oil reserve comparison many different ways with much less energy.
Who are you quoting? National Renewable Energy Labrotory? A panel manufacturer? NASA?
As I mentioned right above the quote, the quote from an article from the September 1995 issue of Scientific American. The author of the article is named “Hoagland”. You can find the back issues at http://www.sciam.com. I don’t know the author’s back ground; that can also be checked at Scientific American’s archives.
Regardless of how you compare it, the sun still imparts more energy upon the earth than we could possibly use if we were to use it. The figure I quoted may be large, but even if you cut it down to 1,000th of what I quoted, it is still far more than our energy reserves. Now, a large part of that energy is unrecoverable simply because most of the earth is covered in oceans, and to recover all of that it, we’d have to cover over the oceans with solar collectors, but the point is that there is more than enough land mass that is uninhabited desert that we aren’t even taking advantage of now, let alone the oceans; if we were even to utilize the solar energy imparted upon the deserts, it would be an enormous amount.
Where did you hear the other solar to oil reserve comparisons? How much energy did they equate it to?
The other ratio I heard was from a sustainable material enthusiast. He was preaching a few fuzzy number comparisons that actually seemed logical. That was really why I wondered where your numbers came from. Getting a blend of information from many people is better than rallying around just one source.
He calculated that we could harness 50% of our daily total energy requirements from solar. The rest of our energy needs would need to come from other sources.
Who has the right number on this? Maybe I should not worry. We can agree oil will run out.
Any way the numbers are cut up, we need to do something. Being off the grid is a step in the right direction, but to really start making an impact don’t we need to get a big solar farm off the ground first?
Biofuel still seems like two steps backwards when compared to solar.
If you think about it, biofuel IS solar; it’s just solar power stored in chemical form by plants. And of course, every step removed incurs losses; plants aren’t 100% efficient, harvesting them and processing them and distributing the material costs energy, and when it comes time to get the energy out, we burn the stuff in internal combustion engines, which usually max out at about 25% efficiency. That’s a great deal of waste; using electric vehicles with a mostly solar powered grid is probably the best way to go (with minimal losses) as far as I can figure.
In fact, by that metric, even fossil fuels are technically “solar”; coal is made of carbon from ancient buried forests, and all the carbon in there was fixed through solar power by plants a long time ago. It’s just that the carbon in fossil fuels has been out of circulation for so long that the atmosphere and the earth has long since adapted to a different set of conditions; dumping all that carbon back into the atmosphere is what’s throwing everything off balance.
That’s what I’m working on, believe it or not. I’m working on an invention that could dramatically boost the efficiency of solar power conversion (in theory). When I have a working prototype, we’ll see how it proves itself. Right now, the world record efficiency for solar conversion is 40.7%; My goal is to top 60%
Things will really take off when solar is not only comparable to the cost of coal, but when solar supplied electricity becomes cheaper than coal. Given that there are no fuel costs, this cost of solar power is calculated in terms of how long the solar installation takes to pay for itself. If the time it would have to operate to pay for itself in savings exceeds the life of the panel (which is historically the thing that has defeated solar power), solar power won’t make sense economically. The goal is to make a solar engine that will pay for itself by the money saved in the least time possible. The time this takes, of course, is intimately dependent on how expensive conventional power is, and right now, the problem is that coal power is very cheap.
The energy companies have a history of throttling the price of coal and oil to keep us hooked; they lower it enough to make alternatives too expensive to invest in when they see a potential threat, and when the threat dies or has its funding cut and everyone is dependent on coal oil again, they jack the prices up against the helpless market with no alternatives. . . until the pain prompts people to remember all the research that got cut, and they start up programs to find alternatives. At that moment, coal prices drop, and so the cycle continues, with their goal to repress renewables research for as long as they can. What happened in the 70’s oil crisis and the subsequent collapse of oil prices in the 80’s was exactly this: the hidden hand trying to crush development of alternatives. The trick is to vote in politicians who won’t forget. That’s tough, because our election cycle has a 2/4/6 year cycle, but the coal/oil price fluctuations happen on the order of 5-10 years.
I suspect that they did that price pumping thing to combat investment in wind; they’ll do the same to fight efficient solar. The only way to beat them hands down is to develop something that is hands-down super efficient, and unleash it and reveal it only to those who need to know when the oil companies are not expecting it and have their prices are high. That way, decisions can be made without the energy companies getting wind of it with enough time to react and kill the alternatives to their supply.