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New Material for More Efficient Solar Cells
PunkerTFC writes "Space.com has an article on a new material that could create relatively cheap solar cells which are up to 50% efficient. This is much better than the 25% efficient silicon solar cells (most common) or the 36% efficient multi-junction solar cells (very expensive). The material was created by "forcing oxygen into a zinc-manganese-tellurium crystal" creating more band gaps, which allow the cell to create electrical energy with three seperate frequencies of light. This could lead to cheap, high-output solar cells in the future, but it will take at least 3 years to assess the feasibility of the new technology, according to the researchers."
It would be awesome to have a car that was able to "refuel" itself while it sat idle most of the time. Cars have so much surface area that is exposed to the sun, it just seems like this would be a great fit, although the sun obviously couldn't be the sole source of power.
Solar cell technology seems to be getting more and more advanced. When will the time come when we are able to use it to effectively power a complete house?
We are there today. In fact, we where there several years ago. The trick is not to need more power than the solar cell generates... so obviously you can easily supply the energy a house needs from solar cells if your house don't need much energy. Say, if you live in the tropics or subtropics, there is no big deal to power everything electrical with solar cells today (even more so if you use natural gas for cooking and running the frigde). If you live above the arctic circle, the day will never arrive that solar cells are efficient enought - since when you need them the most (ie; in winter), the sun just isn't over the horisont... up here it's more a question of efficient storage of the electricity.
I'm more interested in getting really cheap solar cells than super efficiant ones - if I can put up ten cells produsing (say) 1kWh each for the same price I can put up two producing 4kWh each, the cheaper ones are the better choice - as well as making replacing broken arrays cheaper.
Off course, the day I can get solar cells that are both cheap and efficient, I'll pick them without a second thought ;)
Everything in the world is controlled by a small, evil group to which, unfortunately, no one you know belongs.
One alternate plan is to use cheap titanium dioxide to make less efficient solar cells that are significantly less expensive. Titanium dioxide is used to tint paint white and is available cheaply in bulk. While researchers are working on increasing the efficiency through nano particle techniques, do it yourselfers have made progress.
One nice trend is that power companies (and technology) are making it easier for individuals to dump a surplus into the grid for credit. This would allow a home owner to dump power during the day when no one is home, and pull it back at night when the air conditioning, stove, TVs, etc are on, and the sun is down.
One line blog. I hear that they're called Twitters now.
Speaking of nuclear weapons (re: your sig), if the trillions of dollars currently being thrown into the black hole of nuclear research (which includes fusion power) were spent on renewable energy sources like wind and solar, we might have solved many of our energy and pollution problems by now.
OLPC Australia
This is not true. Nowadays cells take up to two years to produce the energy it has been used to build them, and with an expected lifetime of 20 years....
That's only if your equipment needs an awful amount of energy.
According to some simple calculations I did a while ago, my laptop uses about 25W. My laptop's 30x23 cm. So, if I'm right, a panel of that size would produce about 70W.
So, with some luck, if I attached a solar panel to the back of my screen, and sat in some sunny place, I could have my battery not ever run out? Why didn't anybody try this yet?
In fact, this makes me really curious! When I replace this old laptop, I think I could try this experiment. If anybody has any comments about this idea, please reply!
I live in the Arizona desert, and the bright sunlight is BRIGHT (I've built solar ovens that bursted into flames in seconds). I would love to see this energy be put to use, lord knows there's enough of it.
I could imagine huge solar arrays in the middle of nowhere (which is easy to come by in this state) coupled to superconducting magnetic storage coils (made by American Superconductor) to handle the few days that aren't so bright.
*sigh* Sadly, the government in Arizona is more concerned with trying to make the perfect standardized test for high schoolers. Too bad...the power received here could juice up a good portion of the West.
-Matt
Solar sales are up 30-40% every year, and have been growing at such a steady pace for a long time.
Naturally, this is a positive feedback loop. Lower prices mean it's affordable for more niches, which means more people buy, which in turn scales larger. At this point, it's pretty much unstoppable. It is useful in too many niches, especially where customers aren't connected to a power grid.
There are now many countries that have more cell-phones than landline phones. It's likely that in 10 years, some countries will have more customers getting electricity from solar than from a central grid. Naysayers will say it's not ready... but then again, 15 years ago cell phones weren't either. What matters is not the absolute numbers, but the growth rate of the industry and the evolution of the technology.
Of course, as the market matures, more people are doing R&D to find cheaper ways to build PV systems, which is only going to accelerate this momentum.
Information: "I want to be anthropomorphized"
50% efficiencies are quite spectacular. If they could make these things cheaply in high volumes, solar power could be supplying the majority of energy needs in the future.
Those who research semiconductors these days are exploring ever new clever ways to engineer these materials. Mechanisms for tailoring the bandgaps (by introducing materials that strain the crystal lattice) are becoming more widely used. The three different bandgaps allow photons over a wider range of frequencies to be captured and turned into electricty.
It's a question of what we can harness. Enough energy falls on the surface of the Earth every day from the Sun to supply the World's energy needs for weeks, we just can't harness it effectively.
Large scale solar farms in desert and offshore areas would be a very useful source of power for the future, even if it isn't used as a primary, continuous source. An offshore solar farm could be used to electrolyse seawater to produce hydrogen for fuel cells, for example - it is currently expensive to do this because you get out less energy than you put in. Using solar energy though, that doesn't matter because the sun is free (unless the US Patent Office grants someone a patent on "a large ball of gas and dust undergoing nuclear fusion that the Earth orbits around".
SCO will no doubt claim that the Sun also contains System V code. Darl McBride is welcome to visit the sun in an Apollo capsule to inspect it for himself. How he's going to get to the Sun's kernel is beyond me. He'd better pack some sunblock.
It's possible now, but (in the UK) it costs twenty to thirty grand to put a system in. It'll recoup it's cost in maybe 25 years.
The cells you can buy in the stores are more likely to be 15-18% rather than 25% efficient. The 25% ones are fucking expensive and the 35% ones are like rocking horse shit.
Course, energy storage is still a problem for those cloudy days. Batteries are heavy, expensive, made of heavy metals or have to be replaced regularly which isn't exactly "green".
Compressed air energy storage may be feasable on a small scale with the use of a compressed air powered generator, some utilities already use compressed air to store energy on a huge scale. Use solar power to compress air to several hundred atmospheres during the day and run a generator from it during the night and during cloudy periods.
Government of the people, by corporate executives, for corporate profits.
You wouldn't strictly need to locate them in the deserts. If you can produce more value by generating electricity than by groing crops, you'ld see cropland and pastureland converted as well.
If you could even generate electricity at 100 watts/m^2 (10% of solar output), with a long cell lifetime that would stll be enough to make solar power feasible.
However you could use Solar towers. Sorry, I couldn't find a better link. These towers don't use solar cells, but instead rely on having a large volume of heated air trying to escape up a very tall tower and use a turbines up the tower to generate electricity. The heated air comes by what is basically a very large green house.
I used 14 80W Sharp polycrystaline panels connected to a Trace 1500W inverter. I've got 3 85AH Costco deep cycel batteries tied through a 60A trace charge controller. I did the installation and wiring, and also designed and built the monitor and control system. I put a D.C. (switching) supply in the system to supplement the cells when the battery voltage falls below 80%. You see, this is a "Solar UPS" so the batteries always stay mostly charged. When the cells produce less than a few amps of current, the computer activates the A.C. bypass so the inverter and switching supply inefficiencies aren't wasting power. If the A.C. ever fails, the inverter takes over within a few cycles (as a UPS would).
The monitor and control system samples all the voltages and currents 10 times per second. It averages the result and stores everything to a log once per second. The web charts and real-time status come from the log.
A cron job tells me the total power generated each month. The system doesn't run the house, it just runs the server, network, and phones (ISDN & VoIP).
Right now the solar plant is generating about 20% of the total power used here. It lowers the bill by more than that due to the "over baseline" electrical rate accounting system. I've computed that it will pay for itself in 12-15 years.
I purchased nearly everything from eBay so I got a good deal. The cells have a 20 year guaranty.
Since it's not a "grid tie" system (I don't feed any power back), it's not elegible for any subsidy from the power company. Fortunately I was able to deduct 20% of the cost from my state taxes last year. The state (California) does not require the system to be "grid tied".
I hope that answers all of your questions.
Then your wait is over. From the Renewable Energy Myths Debunked article at homepower.com:
Myth: It takes more energy to build PVs than they can ever produce.
Some skeptics of solar energy claim that it takes more energy to make a photovoltaic module (PV) than it can ever produce in its lifetime. The truth is that PVs typically recoup their embodied energy in two to four years. According to an article published by the National Renewable Energy Laboratory (NREL), today's single and multicrystalline modules have an energy payback of about four years, and thin-film modules about two years.
Most PV modules in the field are made from hyper-pure crystalline silicon. Purifying and crystallizing the silicon consumes the most energy in making these PVs. Thin-film PVs are made from considerably less semiconductor material, and therefore have less embodied energy in them. Most of the energy consumed is in the thin-film surface. The aluminum frame on any PV accounts for about six months of its payback time.
Solar energy is an amazing technology considering that PVs go on to produce clean, pollution-free energy for at least 25 to 30 years after they have achieved payback. For more information on energy payback, see the National Renewable Energy Laboratory's Web site (www.nrel.gov) and Karl Knapp & Theresa Jester's article titled "MPV Payback" in HP80.
I don't care if it's 90,000 hectares. That lake was not my doing.
It wouldn't make much of a difference -- they work because the energy of the photons in the light kick electrons off the photoelectric material.
But, light carries the same amount of energy at all wavelengths etc., so making it absorb more just means it would get hotter, not actually generate any more electricity.
If I can store power efficiently, then my solar cells need to generate 18 kWh per day, in about 10 hours of nice, bright sunlight. That's 1800 watts at any given time. At $2/watt, that's $3600 for the array (ignore the storage costs for now).
My electric bill for that month was $55.74, so I get payback in a little more than 5 years.
The problem is, I've seen different numbers for panels. Modules for consumers cost $5.85 per watt, these days. And at that rate, my scenerio costs $10,500, and the payoff time is now 15 years. If I invest that money, and get a 7% rate of return on it, I make more money by PAYING my electric bill ($61.25 per month income, $55.74 payout). It's more profitable for me NOT to install the cells.
The numbers quoted in the previous post for cost drop by growth indicate that (I'd love to see how the math for this is done, properly, but my aproximation follows) those $2 cells will cost $.75 in 2010. Excellent!
But the cost of panels is not all CELLS, and has stayed pretty darn stable. In the past three years, panel cost has only come down a few percent. It went UP some months, too. So we can expect the panels to be cheaper, but not by NEARLY that much.
And in the above I've ignored storage inefficiencies, and support hardware and battery costs.
In other words, I don't think the picture is so rosey.
> Uranium needs to be mined, transported and processed, which requires considerable amounts of energy and destroys ecosystems.
So like coal, except with a much better cost/benefit ratio.
> Once used, nuclear waste needs to be stored. this waste has a half life of thousands of years, and it needs to be put in a place where it cannot harm anyone or anything for this period of time. Obviously we cannot plan that far ahead. Nuclear waste needs to be transported for processing (often through urban areas), and it is usually stored on-site.
Would you rather the wastes and radiation be dispersed through the atmosphere, like we have with our other fuel sources? Personally, I prefer having waste concentrated in a small container.
> Nuclear power makes a tempting terrorist target: blowing up a power station or waste transportation vehicle can easily irradiate millions of people.
Reactor facilities are strongly reinforced, making them awfully hard to blow up.
> Nuclear power stations cannot be decommissioned easily. It is cheaper to keep a station running, meaning that many old, inefficient and potentially dangerous reactors are still operational.
True, nuclear power is the only power source which explicitly factors in the cost of decommissioning and waste management, rather than implicitly leaving the financial and environmental costs to others. Could you point out some of these dangerous reactors you mentioned?
As it stands, nuclear power is the most cost effective and environmentally safe energy source that we have. It's too bad we have such an irrational fear of anything with the word "nuclear" in it.
What you really want is for minimum ecological impact is a "pumped storage" hydro plant. Build a man-made reservoir at the top of the hill, and a basin at the bottom of the hill. Fill the top reservoir with water. During the day, you let the water flow with gravity downhill through a set of turbines to generate electricity. At night, power the turbines to flow in reverse, and pump the water back up to the reservoir, basically "refuelling" itself.
But, you say, what's the sense in doing that? Conservation of energy says motors use more energy than they can generate in reverse, so aren't you wasting electricity just moving water about? You'll go out of business!
The key is not the volume of water, but WHEN you're generating. In deregulated energy markets like in most of the USA, there is also an ebb and flow to the price of electricity along the day... at night, when people are sleeping, there's too much online supply and not enough people using it, so the price drops... and during the day, when everyone is awake and watching TV and cooking and cleaning and working and computing, the demand for electricity is much higher, therefore the price of energy is higher.
So, generate electricity during the day and have people buy from you at higher rates, and run your pumps at night purchasing electricity from someone else for lower rates. Net, you're making money, keeping your average costs low. Not only that, you avoid erosion and killing fish like you do with conventional run-of-river dams. For an impressive beast of a plant, check out Bath County Station in Virginia.
Green self-sufficient (sum) heating is becoming quite common here in northern Europe. Now we need a personal dc grid for appliances because converting solar to ac and then heating all these ac-dc bricks all around the house seems quite wasteful.
... get real! Some things are just energy wasters.
I think standardizing on something like FireWire 800 wallsockets to universally replace the ac-dc bricks. Most appliances can live on the current allowed by the FireWire standard.
The grid itself would have thicker copper cables to supply multiple FireWire sockets in paralel with enough current to allow each socket to supply the full specified current of 12 Watt.
Most home appliances can make do with 12 watt if you design them that way many waste most of their energy on the power brick:
60 Watt lightbulb = 9 Watt energy saving bulb
75 Watt lightbulb = 11 Watt energy saving bulb
1200 Watt vacuum cleaner = 12 Watt vacuum robot which takes days instead of hours but you don't have to push it around those hours.
1000 Watt dishwasher = 2 Watt dishwasher if it can get water heated with the sunheater next to your solar panels.
2500 Watt washer / dryer
--
Dennis SCP
I never really heard about it requiring more energy, but what I did hear about is that it requires producing hazardous chemicals. Amazingly, I did RTFA, and found their answer to this wanting. If you are going to "debunk" myths, please use... actual numbers. As I read it, this document is primarily directed at people who already want to believe its conclusions. I'm not saying this to be hostile.... I just honestly wanted an answer to this and was disappointed they didn't give one.
..... Nukes produce nuclear waste is only a detriment if you already accept that nuclear waste is bad (or at least worse than anything else).... which is the statement they are trying to prove
and chemicals used must be disposed of in an environmentally sound manner.
And how is that exactly?
By using well-designed industrial processes and careful monitoring, PV manufacturers have minimized risks to where they are far less than those in most major industries.
One, I'm not sure what exactly they are talking about here: They bounce back and forth between discussing the safety of the workers, and the environmental impact. I suspect that this quote was in context of risks to workers, but it is presented as risk to the environment
Secondly, What is "most major industries". I suspect that they compared PV cell production to other industries where you have to use other similar processes and chemicals to refine your materials. Lets say you have to use similar silicon techniques for PV cells and microchip production (I don't know about this). It is all well and good to say "We're no worse that other industries that use these chemicals to produce our product", but this is really skirting the issue because you aren't addressing the issue of whether you have to use that process to produce electricity. You have to use these chemicals to produce microchips, you do not have to do so to produce electricity.
This is the central question to the debate, and they have not addressed it, but merely changed the debate to a question of whether their industrial process is worse than other industries with the same process.
They also did not address the issue of environmental impact of the batteries that you need with the photo cells.
Nukes produce nuclear waste, and even after spending billions of taxpayer and ratepayer dollars, no acceptable disposal solution has been brought to the table
This is a good example of "Begging the question"
Again, the reason "no acceptable disposal solution has been brought to the table" is because they will not accept any solution as acceptable because it involves nuclear waste.... They have to answer: why is burying nuclear waste so much worse than burying toxic chemicals produced by PVC and battery production?
Again, as a solar supporter I'm sure you run into hostile questioning.... but do not consider this... I am truly some one who wants to believe solar is a viable solution, but I am looking for hard numbers to justify this and I have not found it yet.... hope you can supply this.
---Lane
You can do the vast amount of work yourself, save thousands, literally thousands. shop around for the various components. it is no way any harder than building your own peecee, just much larger. You have panels, their mounts, some simple wiring, a charge controller, then usually an inverter/charger for adding grid juice into the mis, and a battery bank. You run the output to your panel box you already have, or just pick a few circuits to power. You can hire an electrician to look it over one day and do the last install to the panel, that's really the only person you need to hire. You *might* need a permit, that varies locale to locale, same as any other home construction action. It's just not that hard if you can use a few normal tools and first sit down and plan out what you need and the steps to take.
As to the batteries, look into a local forklift dealer, look at their traction battery banks for the electric forklifts. Significantly cheaper per amp-hour than deep cells with "solar" printed on them. they come into 12VDC to 48VDC configs, pick out what ya need, it'll probalby run at least 50% under "solar" batteries for the same amp hours.
And look into the new "desulphator" devices to keep batteries and battery banks clean (they run 100-150$ or so), they will keep batteries working MUCH longer than batteries without them, and are very cheap for what they do. I have some deep storage batts I use (some cheap 6 volt golf cart batts, wired in series, then parallel to give me 12 volt dc circuitry) that are still fine,and are already a few years past when they were supposed to go bad according to the literature for them, I got a desulphator and it cleaned them up just spiffy within a few weeks.
The way to deal with alternate energy is work both ends towards the middle, reduce consumption (better apliances, saner useage, better built home with more insulation, better natural lighting, etc), then add in your production, at some point you'll hit a sweet spot where those two personal supply/demand lines cross and you are independent and it becomes very affordable.
And it IS a concern with the politics involved with electricity, and here's something else to consider, with solar (any alternative energy scheme really), you can get an upfront, bottom-line price. With grid supplied, you have zero guarantees on the price a year from now, 5 years, ten years, etc. You are going on a price comparison for looking at years in the future which has no basis in any contract you have, because it doesn't exist. Various areas in the US have had doublings of rates in as little as a one year time span, and it RARELY ever goes down, does it? As far as I know, no utility out there gives a homeowner even a chance at a set carved in stone price/contract for KWH for 10 years from now. You have NO idea what it might cost in the future, nor will you know if it will be even available like it is now, we live in an uncertain world, yes?; and "energy" is sure a politically connected product, so you never know what might happen......
The second consideration is, why do you have to jump to whole house? Just use it as a daily adjunct (for your home office and boxes, it's a great UPS system for example), and as a backup to have *some* power if/when the grid goes down. You might not have enough to run the AC if it's a heatwave and the grid borks, but you can still run some fans, for an example, along with some small appliances, your boxes, a radio maybe, etc. it's a backup for a critical thing for most geeks,, ain't a one of us here DON'T not-like electricity, if I am allowed that double negative. We dig JUICE, so having at least some of your own juice you can control is *slickerissimo*. No law says you have to have either/or, you can have both, just be smart about the first install and scale the components (notably the inverter/charger/controler parts) so you can add to the PV array and the battery banks as you can afford it and have more interest in it. So instead of dropping 20 grand, try 5 with some on site stora
Current estimates of world oil reserves (total)
is around 2 trillion barrels.
The energy stored in a gram of oil (on average)
is 44000 Joules/gram, at a SG =0.9.
1 barrel (oil) = 42 gallons = 0.159 m^3
So 1 barrel has the following energy content,
44 x 10^6 Joules/kg * 998 kg/m^3 * 0.159 m^3/barrel * 0.9
= 6.3 x 10^9 Joules/barrel (6 gigaJoules/bbl)
So all the energy stored in the worlds
oil reserves is,
2.0x10^12 barrel * 6.3*10^9 Joules/bbl =
1.3x10^22 Joules of oil energy.
(2.0x10^12 is a very optimistic value, P=0.1)
Ok, so you think this is a big number ?
The total power radiated from the sun is approx,
4x10^26 watts or 4x10^26 Joules/sec.
The sun radiates the equivalent of all the energy
stored in oil on the earth in,
1.3x10^22/4x10^26 = 32.5 microseconds
The entire oil based world economy (150 years of work)
is only a 32 microsecond job for the sun.
By necessity "we" will become much smarter on how
to capture solar power.
BTW the current world rate of oil consumption
is approximately 80x10^6 barrels/day, at
this rate the remaining 1.5x10^12 barrels
will be gone in, 51 years. The growing South
Asian market will probably help cut this to 30
years, but shifting demand will probably help
keep complete cut off at 50 years.
The Californian experience with deregulation and deregulation experiences in general have proven that American Businessmen are just assholes who want to screw you for the very last penny. The phone companies are another example of a botched deregulation.
And I'll bet you think China is really a republic, too. After all, they say they are.
News flash for you. California never deregulated their energy industry. The phone companies were never deregulated, either. Both industries were re-regulated. They were just given new regulations to follow and the politicians went around telling everyone the industry had been de-regulated.
You can tell a great deal about the character of a man by observing those who hate him.
I have thought of a possible solution, though I don't know if it will work. I would love for someone to try this possible solution, and let me know their results.
Basically, I am thinking of using a piece of alluminum plate/sheet for the back electrode, painting the alluminum plate with copper-oxide containing anti-fouling paint (used to keep barnacles and other things off boats and ships - must have a very high percentage of copper oxide for this to have a chance in hell of working), then, while the paint is tacky, pressing a piece of copper mesh onto it (to form the front electrode) - hook up wires, sandwitch between some clear acrylic, and...profit?
Would this work? Would this be a cheap way of building solar cells? Would it be cheaper than silicon-based cells? Cheaper than used cells (likely not)?
Actually, I know of a way to get real cheap solar panels, which I am currently exploring - hopefully, something good will come out of it...
Reason is the Path to God - Anon