Solar Panel Breaks "Third of a Sun" Efficiency Barrier 237
Zothecula writes "Embattled photovoltaic solar power manufacturer Amonix announced on Tuesday that it has broken the solar module efficiency record, becoming the first manufacturer to convert more than a third of incoming light energy into electricity – a goal once branded 'one third of a sun' in a Department of Energy initiative. The Amonix module clocked an efficiency rating of 33.5 percent."
Additional Information (Score:5, Informative)
Send it into space! (Score:2)
If you move the panel closer to the Sun, you'll need quadratically less area for the same amount of energy.
Of course, you'll need a parallel laser beam to send the energy to Earth, and a receptor, etc. but those are left as an exercise for the reader.
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Honestly, it'd probably be much easier just making a HUGE ass magnifying glass in space
Magnifying glass? Are you insane? A thin silver-covered mylar mirror is much lighter than that.
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Stefan–Boltzmann says that the radiation from a black body is proportional to the fourth power of its temperature. You would have to add a lot of energy to make any significant difference to temperature.
Go ahead, build and sell it without subsidy (Score:5, Insightful)
That's just about where the miracles stop reliably. You may or may not find some special cases in which those actually make sense (given that we're talking about concentrated solar and 2-axis drives are mandatory, those cases become even more special), but at large scale it's just not worth it - even without considering the need to store the energy, so you have it when you need it.
yet another solar tech not available to the public (Score:5, Insightful)
Every 6 months on Slashdot we read about higher efficiency solar panels. Virtually none of them are available on the market, and if they are, they're only available to large-scale commercial installations. Right now, the best you can do retail is about 20%; some panels are barely 10%.
A condition for any prize should be "available in half-dozen quantities to individual purchasers."
The best return on investment remains solar hot water - we're talking an order of magnitude in efficiency per area between common solar panels and evacuated-tube hot water collectors. We waste enormous amounts of energy heating hot water and heating homes...
We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
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you can't build nuclear bombs from solar panel materials.
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I think the prevalence of gas-powered dryers is a reason the U.S. still uses more inefficient dryers, because the fuel (natural gas) is fairly cheap, and much cheaper than with the electric-powered dryers that are prevalent in parts of Europe. So there's less economic incentive to improve efficiency.
Re:yet another solar tech not available to the pub (Score:5, Informative)
http://ths.gardenweb.com/faq/lists/laundry/2004120958010854.html
"All else being equal (i.e. not including household heating/cooling issues), condenser dryers are slightly less efficient than their vented counterparts, typically on the order of ~15%. The real design intent of condenser dryers isn't improved efficiency, but the simple fact that they don't require a vent duct, permitting easy installation most anywhere (ideal for apartment dwellers, etc). "
A gas dryer is going to be much more energy efficient than an electric dryer considering that ALL the heat generated from the flame enters the tumbler. Typical power plants can only transmit up to ~40%% of the heat from their power source to the dryer heater coils.
Min energy eff electric: 3.01 lb/kWh
Min energy eff gas: 2.67 lb/kWh
Electric is 12% more efficient at point of use
Total heat efficiency including power generation:
3.01 * 40% = 1.2
2.67 * 100% = 2.67
most efficient setup would be an external venting gas dryer in a unheated space like a basement or garage since you would not be adding load to an HVAC system.
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You are at least 5 years out of date with that information. Traditional condensing dryers are obsolete, modern ones use heat pumps and are vastly more efficient than vented dryers.
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You are at least 5 years out of date with that information. Traditional condensing dryers are obsolete, modern ones use heat pumps and are vastly more efficient than vented dryers.
Our heat pump dryer is awesome. Expensive, but awesome. Prior to that we were often hanging clothes inside to dry (hanging them outside brings in the pollen which is very bad at this time of year (Spring in AU)). With our one we have to empty out the water tub manually, and it's amazing to see how much water used to be evaporating into the house!!
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OK, some more math
http://www.topten.info/uploads/File/040_Rita_Werle_final_driers.pdf
efficiency of heat pump condensing dryer
best in market (according to report)
0.23 kWh/kg = 8.15lb/kWh
worst in market
0.4 kWh/kg = 5.5lb/kWh
Euro A grade requirement
0.48 kWh/kg = 4.58lb/kWh
efficiency of power generation facilities
http://www.eia.gov/electricity/annual/pdf/table5.3.pdf
natural gas = 3412/8185=41.7%
coal = 3412/10415=32.8% (roughly same as nuke plant)
distribution losses
http://data.worldbank.org/indicator/EG.ELC.LOSS
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At this stage cost a more important factor than efficiency. We have vast amounts of unused space that could be covered in solar PV panels, but the fact that it takes years to recover the investment of thousands of Euros/Dollars is holding back adoption.
Re:yet another solar tech not available to the pub (Score:5, Informative)
It looks like I can buy solar modules for a minimum cost of $1/Watt.
Assume an energy cost of $0.1/kWh. Assume an average of 12 hours of sunlight per day and a 50% of maximum average intensity.
$0.1/kWh * 1 year / 12 * 50% * 12 hours/24 hours = $0.01826
The monthly value that a solar cell generates is $0.01826/watt month.
Assume a yearly interest rate of 5% (monthly is 0.4074%)
Since the cost of a solar cell is $1/watt, work out the number of months that a 1W solar cell must run for to generate $1.
PV = A/i (1-1/(1+i)^n)
PV = $1, A = $0.01826, i = 0.004074
n = 62 months = 5.17 years
The warranty on the reference cell is 10 years product workmanship, 25 years linear power.
So the value of the cell over its 25-year life span is $3.15/watt, with a cost of $1/watt.
This all neglects installation and grid-tie costs, but 50% average illumination per daylight-hour is conservative in most areas. Solar cells ARE worthwhile TODAY and WITHOUT government subsidies.
Efficiencies in solar cells are irrelevant. The only thing that matters is the $/Watt.
Reference Solar Cell: http://www.affordable-solar.com/store/solar-panels/CSI-CS6P-245P-245W-Solar-Panel-STD-Frame
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It actually continues to work for you even after you leave. Adding renewable energy generation and high efficiency heating/cooling (geothermal) to your home increases your property value, which gives you the option to do the same again, or buy one with the work already done.
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This shouldn't really matter, as any unrealized value of the PV panels would presumably be recouped by increased resale price of the house.
The hang-up is up-front costs. The average home in the U.S. uses 11,500 kWh [eia.gov] in a year. So at a constant power draw that's 1311 Watts. Factor in PV solar's average capacity
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The hang-up is up-front costs. The average home in the U.S. uses 11,500 kWh in a year. So at a constant power draw that's 1311 Watts. Factor in PV solar's average capacity factor o 0.145 and that means you need 9050 Watts of nameplate capacity installed to (on average) zero out your electricity bill (in reality it's a bit less because peak electric prices are during the middle of the day when nobody's home but the panels are generating the most).
In my region of California, residential electricity costs are tiered, with Tier 3 (starting at 418kWh/month, or about half of the average you stated above) breaking 24 cents per kWh, and continuing to Tier 5, still less than the monthly average usage you quoted, running over 32 cents per kWh.
Any renewable energy system that can take kWh off the top of that stack will pay for itself in very short order around here.
Re:yet another solar tech not available to the pub (Score:4, Informative)
Average capacity factor for solar in the U.S. is about 0.145. That is, a 100 Watt nominal panel will on average generate 14.5 Watts throughout the year after factoring in everything - night, weather, angle of the sun, etc. In the desert Southwest it's about 0.18 (0.195 in extreme desert regions), but for the country overall it's about 0.145. The NREL assumes a capacity factor of 0.17 [nrel.gov] for PV installations in the U.S., which are predominantly in the desert Southwest.
Your quick "12 hours a day, 50% max average" assumes a capacity factor of 0.25. Almost twice the actual value.
Correct for this in the rest of your math and you get n = 120, or 10 years payback. That sounds about right as the test cases I've calculated usually wind up between 7 and 15 years.
Re:yet another solar tech not available to the pub (Score:5, Informative)
Click on your city. Click 'send to pvwatts'. Enter the solar system size in kW (default is 4.0). Click calculate.
Depends a great deal of where you live, of course, because energy prices and solar radiation vary quite a bit across the USA.
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So the value of the cell over its 25-year life span is $3.15/watt, with a cost of $1/watt... Solar cells ARE worthwhile TODAY and WITHOUT government subsidies. Efficiencies in solar cells are irrelevant. The only thing that matters is the $/Watt.
That's interesting. Please also compare:
* If you invested $1 in the stock market, and see how much it grew in 25 years, minus the cost of the energy you'd need to buy.
(I suspect that 315% over 25-years is much smaller return than what you'd get from stock market growth).
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(I suspect that 315% over 25-years is much smaller return than what you'd get from stock market growth).
Stock market growth roughly matches GDP growth in the country. If you think the country's output is going to grow more than 315% in the next 25 years, then that's a good bet.
Looking at the future from the way things stand right now, we're in for a rocky few years at least. It is not at all a sure bet that we will manage to get a 315% return over that period, and the stock market could drop more as baby boomers remove their money from the market. Plan accordingly.
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PV = $1, A = $0.01826, i = 0.004074
n = 62 months = 5.17 years
The warranty on the reference cell is 10 years product workmanship, 25 years linear power.
So the value of the cell over its 25-year life span is $3.15/watt, with a cost of $1/watt.
This all neglects installation and grid-tie costs, but 50% average illumination per daylight-hour is conservative in most areas. Solar cells ARE worthwhile TODAY and WITHOUT government subsidies.
Efficiencies in solar cells are irrelevant. The only thing that matters is the $/Watt.
Efficiencies in solar cells are irrelevant - as long as they are constant. The 25 year linear power guarantee is that you will be at 80-90% of the rated power after 10 years, and 60-80% after 25 years. I don't think you will reach a value of $3/watt under those conditions; on the other hand investing that initial dollar at 5% will get you to at least $3.30 by year 25. If you're looking at it as a straight investment proposition I think you need to consider the subsidy vs installation/maintenance/degradation
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Yes, solar makes a lot more sense at those prices.
However $0.10 is on the high side for the U.S.
You can get it for .09 in my state if you sign for 12 months instead of "locking in" a low rate for 36 months like i did.
In many other states, you can get it under .09 if there is a dam anywhere near you.
At $.25/kwh, $2.50 to $3.00 per day per panel average your payout period would be about a year.
FWIW, I get a much better return by replacing lightbulbs with LED and CFL bulbs. CFL still suck so I prefer LED. Ev
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We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
You're wrong. If everyone drove half, used 2x efficient appliances, etc it would work until the population doubles. Then we're right back where we started. If they start creating energy from "nothing" like sunlight, we can use all the energy we want at any rate at any population level.
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The population is unlikely to double.
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Wait the condensing ones are more efficient?
I know they are vastly more expensive to purchase upfront but I was under the impression they are also terribly inefficient, the advantage is they don't mould up the bathroom with a lot of water condensation?
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PLUS: you get double points on your geek card!
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That's simply not true.
I was looking to reduce my electricity usage, so I bought myself a decent clothes rack, and stopped using the dryer. But then I actually purchased a meter and measured the power usage of my dryer and calculated that it would take me five years to pay back the $50 I spent on the clothes rack. The amount of power the dryer used was utterly insignificant in the scheme of things. However, since then my dryer broke down, and I've never bothered to buy a new one, because the clothes rack
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$50 on a clothes rack? Was it Martha Stewart Signature Series product?
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If the condensing dryer is a closed loop, then surely the "exhaust" runs over the cooling coils where the moisture is extracted (by condensing...) and the heated again before passing through the basket. There wouldn't be any point in releasing the exhaust, as you'd just have that much further to heat the new incoming air.
Why else would it even be called a condensing drier?
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We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
"...All else being equal (i.e. not including household heating/cooling issues), condenser dryers are slightly less efficient than their vented counterparts, typically on the order of ~15%. The real design intent of condenser dryers isn't improved efficiency, but the simple fact that they don't require a vent duct, permitting easy installation most anywhere (ideal for apartment dwellers, etc)..."
"...There IS in fact a true heat pump dryer - the AEG Lavatherm WP - which is very energy-efficient, but it's not available in North America, and is extremely expensive (probably so much so that it wouldn't pay for itself in energy terms)...."
Source: http://ths.gardenweb.com/faq/lists/laundry/2004120958010854.html [gardenweb.com]
Bosch and Meile both make heat pump dryers, probably more brands these days - it's a few years since we last looked. We have a Bosch. It is expensive, and probably won't ever pay for itself in terms of energy savings, even in our household of six people, but we can't easily vent a dryer to outside here so the heat pump dryer made a lot more sense. It's also fast.
When we were looking, the condenser dryers sounded awful. Inefficient and really slow to dry.
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because western europe has a culture rife with insecurity and individual powerlessness. This breeds passive aggressive behavior such as this. Unfortunately this crap is breeding here in america too.
Concentrated solar is less efficient (Score:5, Informative)
Unfortunately, this is a concentrated light solution. This means that the figures quoted for efficiency are in the presence of direct sunlight. However, this is only a proportion of energy generated from PV modules, hence the "efficacy" and therefore, total energy production, of concentrated solar solutions is less good than unconcentrated modules.
The reason comes from diffuse sunlight - light that has been diffused by the atmosphere or by clouds. This typically accounts for 10% of module illumination in direct sunlight, and much higher in the presence of atmospheric haze/cloud; even in lightly overcast conditions, you can expect unconcentrated PV to yield approx 10-15% of direct illumination yield because of the diffuse illuminance.
Diffuse light cannot be concentrated by optics, thus concentrated solar PV modules cannot utilise the diffuse light (more precisely, they can utilise it, but not concentrate it - thus if the system uses a 10:1 concentration, then the energy yield from diffuse illumination falls from 10-15% to 1-1.5%).
A boost from 30 to 33% efficiency by switching to concentrating modules could be completely wiped out by the loss of diffuse yield, even in direct sunlight. In non-direct sunlight, hazy or cloudy conditions, the yield can be reduced much more severely; resulting in a net reduction in productivity, despite the higher nameplate efficiency.
This technology is most suited to areas with the most intense direct illumination; e.g. dry areas, at low latitudes (where the role of diffuse light is diminished in proportion).
Re:Concentrated solar is less efficient (Score:5, Insightful)
No. A 2-axis tracked CPV system with multi-junction cells will produce more with beam radiation than a 2-axis tracked monocrystalline PV system with global radiation, at least in the regions where CPV is installed (Spain, Israel, Arizona, ...).
Sure, it won't work well in Norway.
Diffuse fraction never falls below 16%. Even a clear, deep blue sky still emits diffuse radiation.
True, but we're probably talking 500:1 concentration, here.
33% has been measured under 850W/m2 direct radiation (nominal operating conditions). Compared to 1000W/m2 global radiation (STC), you get 15% less.
That's still about 28% of module efficiency. How many single-junction PV modules are there that deliver that much, even in laboratory? None.
You meant "high altitudes", right?
I'd do it tomorrow (Score:5, Interesting)
It was new, purpose built, so had some obvious advantages, but what I took away from it was:
Obviously location and climate matter, but at the end of the day it was a viable and practical option, and one that made economic sense as well.
Sooner or later some bright government will figure out that by heavily subsidizing the installation of solar in homes they'll a) Develop a very viable industry b) drop solar costs due to volume c) get relected because everyone's electric bills will drop d) boost the economy because the money that was going to the electric company can be spent elsewhere. Now, I'm still a fan of hydroelectricity - if you need to generate electrical without generating CO2 and pollution, and without the no-nukes crowd at your door, there isn't a better way to go.
Re:I'd do it tomorrow (Score:4, Insightful)
Sooner or later some bright government will figure out that by heavily subsidizing the installation of solar in homes...
That's already being done all over the US--has been for years. Yet solar PV is still barely viable economically, even when the government pays 30-60% of the cost.
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Sooner or later some bright government will figure out that by heavily subsidizing the installation of solar in homes...
That's already being done all over the US--has been for years. Yet solar PV is still barely viable economically, even when the government pays 30-60% of the cost.
No, heavily subsidizing. Let's see if I've got the correct question. Where is Germany. That is correct, let's see how much they wagered. Germany leads in solar because they lead in subsidies. I have my own issues with subsidies but it seems to have worked in this case. In the US there's too many places and cases where you can't get the subsidy, many of which coincide with some of the best places for solar installations, almost like they intended it.
Re:I'd do it tomorrow (Score:4, Insightful)
Germany leads in solar mostly because it's quick, easy, and therefore cheap, to get solar projects approved there. It's a nightmare in the US, at least the city where I live; I've been going through this for months: already dozens of pages of blueprints, specifications, calculations etc filed, thousands spent, and still no end in sight.
http://www.forbes.com/sites/toddwoody/2012/07/05/cut-the-price-of-solar-in-half-by-cutting-red-tape/ [forbes.com]
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There are solar companies that will evaluate your site for free and install a system on your roof under a variety of terms. I believe there's at least three major firms doing this more or less nationwide in the US today. They focus on the southern states for obvious reasons and they don't operate in states where there's the least incentives.
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Barely viable economically?
Yes.
You might want to look at how many houses are getting solar added every year. From experience I can tell you that it's thousands of homes per month and the pace is steadily increasing. When you consider solar on your home compared to the utility in your area over the next 20 years...
Yes. Now, how many homeowners have you talked to after they've had PV for 5 years? Yep, like any other product you can buy, the sales pitch overstates the savings and understates maintenance. (Yes, PV does have maintenance, cells fail occasionally. Worse, many of the cheaper panels, especially the ones that big builders are using in new development, have the cells wired in series--no joke, one cell fails, the panel fails.)
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I hate to be *that guy* but in the interest of fairness, while hydroelectric doesn't emit CO2 it does apparently emit a good bit of Methane from algae/sediment. I don't know however whether that's methane emission that is due to hydroelectric or no net increase in Methane from redistribution of methane that would have been released somewhere anyway. But it's something to consider.
Personally I'm a big fan of the Nukes.
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But in the further interests of fairness, this is more a feature of the reservoir than the hydro plant itself. So even non-power-producing reservoirs emit methane.
Also, the methane emissions can be greatly reduced by clearing the area of trees and plant life before filling the reservoir. This brings it down to roughly the level of a natural lake.
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Now, I'm still a fan of hydroelectricity - if you need to generate electrical without generating CO2 and pollution, and without the no-nukes crowd at your door, there isn't a better way to go.
You get the "don't destroy the environment by flooding it" people at your door. Seriously, there's a big fight over this topic right now in California over Hetch Hetchy reservoir.
Re:I'd do it tomorrow (Score:5, Interesting)
Anyhow, if there were any real market for alternative energy (especially Solar, as I live in the middle of Texas), my electric co-operative power company would already be using it.
What if electric was a net gain (returns 5% on investment) but doesn't meet the minimum 10% ROI for the coop to implement it? What if the issue is that, if land and backhaul were free, it would be marketable, but a power company building a solar plant doesn't get free land and free infrastructure? You do. You've already bought the land your house is on, and paid for the infrastructure to that house, so the land and infrastructure are free. Just because someone can't make a profit on selling it doesn't mean it isn't worth doing. If every home in the US had panels on the roof, that would eliminate the peak summer loads, and would supply a surplus so that storage, rather than peak generation, would be the next problem to tackle. And the industrial sites would always use more than they can generate, so we'd end up where industrial sites would pay the power company, and the power company would pay millions of home owners.
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Your land and "infrastructure" aren't free just because you've already bought them and no one else's business plan matters when you do your own cost/benefit analysis.
You have any numbers to back up your claims of energy surpluses?
We can have surpluses simply by building too many generation plants. I don't see that as a benefit to anybody, nor do I see tackling the resulting storage problem as anything other than two wrongs making a right in your mind. Solar energy isn't free, so producing too much of it i
Re:I'd do it tomorrow (Score:5, Insightful)
A carbon tax, if done correctly, would be much better than subsidies. The problem is: a subsidy means that the govt gives some people money. A tax means that the govt takes some people's money. Which do you think is easier to get through Congress?
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"Which do you think is easier to get through Congress?"
Bad question. The former cannot exist without the latter.
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enough taxes.. it's obvious that governments don't have the discipline to use other peoples' money efficiently or to use their taxing powers non punitively. Governments and corporations have plenty. it's time for them to quit giving each other hand jobs and start fixing the stuff they claim they can fix instead of hoarding power and resources for the elite.
101%? (Score:2)
So if we get past 100%would that create a black hole that sucks in energy for everything around it and ultimately would destroy the earth? Just askin'
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So if we get past 100% would that create a black hole that sucks in energy for everything around it and ultimately would destroy the earth? Just askin'
With your 150% efficient solar cell, and a light bulb shining on it (that could convert electricity into light usable by the solar cell at more than 66% efficiency, which I think also doesn't exist) you would have a "free energy" machine.
Current solar panels with microinverters $1000/$36 (Score:3)
Okay so current panel I bought for $1080 with mounting appears to be producing about $3 of electricity per month. I'll get a $300 credit on my taxes this year.
It's simple and I just plugged it into an out let and my "kilometer" shows it's producing power.
But $700/$36 = 19 years.
It will probably break before it reaches break even.
However--- if electrical power doubles like it has since the 1980's (5 c/pkwh vs 10cpkwh)
Then it would pay off it about 12 to 15 years.
Solar isn't "there" yet.
And the panel went up from $1080 to $1280 after I purchased it.
Solar isn't "there" (Score:4, Informative)
Maybe not for you.
Most states have more expensive electricity than $0.10/kWh.
Also, most people who have solar go on a time-of-use rate where they can sell back power in the day when electricity is worth more and then buy it back at night when it is cheaper.
My array will pay back in about 9 years. Less with the tax rebate. And it cost less than $1280/panel installed even before rebates.
When did you measure the panel? Even at $0.10/kWh it should make a little bit more power than that during the summer. My panels are making about 800Wh a day a piece right now and the days are very short at the moment. They make nearly double this much during the summer months.
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okay ... so your panels are producing 1.6kwh vs my panel's 1kwh.
So that's 16 cents a day instead of 10 cents per day. Or about $4.80 per panel per month instead of my $3.00 per panel. So $60 per year instead of $36 per year.
You say your payoff is 9 years...
$1280/60 = 21.3 years.
using a little algebra
$X/60 = 9.0 years or $540/60 = 7.0 years. Wow, if you seriously got your 1.6khw panels, installation, and inverter for $540 per panel that's a phenomenal deal. You can't get close to that for retail instal
Re:So confusing... (Score:5, Informative)
From the article: "The solar module efficiency is the efficiency of the panel, and not the same as the efficiency of individual solar cells from which it's comprised. At the moment, solar cell efficiency can just exceed 43 percent for concentrated systems. It's the module efficiency, however, which reflects the amount of electricity a PV system can produce."
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Re:So confusing... (Score:5, Informative)
If anyone reads the article carefully...
They state in the article that individual cells can already reach 43% efficiency - which matches the top end of that chart.
The overall efficiency of the PANEL (made up of many cells) is lower though. This 33% is the record for the efficiency of the PANEL as a whole, not for the individual cells.
Re:So confusing... (Score:5, Informative)
Why not cite NREL's official and current chart? http://www.nrel.gov/ncpv/images/efficiency_chart.jpg
While they may have hit a new record for overall efficiency, any sort of concentrator photovoltaics require sun tracking, significantly increasing initial system and maintenance costs.
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The real question is what will the efficiency be after 10-20-30 years?
Re:Solar cells (Score:4, Informative)
Christ, I love it when people with zero actual experience with things dump on those things just because it makes them feel good.
Materials price:
Been dropping FAST for about three years.
Install cost:
What? You mean the cost of paying an installer? Or the cost of DIY? Neither is high.
Batteries suck:
"Batteries never die, they're always murdered". Mine are 22 years old and test the same as when new. Why? Because I don't try to fuck them like a big pile of lead-acid bitches.
Motivation:
WTF? Either you want to, or you have to, or you don't. I had to. And I wanted to. You? Guess not.
Home built panels:
Almost "why bother?", considering how inexpensive the commercial models have become.
Hail:
Are you fucking kidding me? Seriously? You do know regular commercial brands are warranted up to golf-ball sized hail? In one insurance claim, an entire RV was written-off due to tornado hail damage. The only thing salvageable? The PV array. It was undamaged.
Listen, there's a whole World of shit I know nothing about. So, what I don't so is talk about that shit as if I'm a fucking expert on the subject. Because I'll just look like a cunt if I do. Give it a try.
Re:Solar cells (Score:4, Insightful)
Almost "why bother?", considering how inexpensive the commercial models have become.
Even with gov't subsidies, you are looking at a 15 year ROI - you think that is why bother?
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One has to account for the added value of having backup power during grid outages, and the increase in home resale value means you don't have to actually remain the owner for the entire period of the ROI to realize a gain. That, and your 15 year figure is ancient.
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Does anyone have any confidence that the AC who wrote that statement knows what "margin of error" actually means?
Re:Margin of Error. (Score:5, Funny)
I'd say it is 80% certain that he does not, with 2 sigma confidence
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Oh snap, nerd burn ! ;)
Re:**YAWN** (Score:5, Insightful)
If you include external costs, it's a lot closer than you think.
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If you include external costs, it's a lot closer than you think.
Go on. Show me the mone...maths!
Re:**YAWN** (Score:5, Interesting)
For almost any new building it is worth covering the roof with solar PV. It might take 10-15 years to recover the cost, but then it is all profit. The savings are even bigger if you combine PV with solar heating. Installation is cheaper at the time of construction and the cost is a small fraction of the roof budget, let alone the cost of the whole building. If you are taking a mortgage then the cash from feed-in tariffs will more than cover the extra cost of the panels on your monthly payment.
Note: Based in building in the UK, further south it makes even more sense.
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What is the "life expectancy" of PVs?
Re:**YAWN** (Score:5, Informative)
typically 30 years with 80-90% of the original efficiency, less if you live in a hurricane / tornado prone region.
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Re:**YAWN** (Score:4, Informative)
25 years for reasonable ones. Of course by the time they wear out you will be able to replace them cheaply as you already have the mounting hardware and electrical infrastructure.
Re:**YAWN** (Score:5, Interesting)
Re:**YAWN** (Score:5, Informative)
Solar cells and silicone sealant share the same property: we have no idea how long they're good for.
Originally silicone cement had a 3 year warranty. Then none failed and they made it 10. Now it's 30. I have aquariums that are forty years old that have just a microscopically thin lawyer of silicone holding hundreds of gallons of water in a glass box. We have no idea how long the stuff will last, it could be a hundred years or more for all we know.
Solar panels started being deployed in the 70s. They all still work and were expected to give 10 years service. To be sure, efficiency diminishes over time, but that's a secondary consideration to the fact newer panels are much more efficient. Somebody can use those old panels though.
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Actually, while solar cells have an extremely long lifetime, solar modules are much more short lived. Many of the panels deployed in the 70s failed after only a few years. The main reason is that the electrical connections must survive thermal cycling. Thermal cycling also can cause delamination of materials (for example the front glass and the Si wafers). Once the module is damaged, corrosion can continue to further degrade the panel. Modern panels have more engineering to prevent module level failure, but
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That can't be true. Lawyers are made of 'poxy.
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It already is. Once you set up the panels, the price per watt is 0 (which is less than non-renewable sources, and as low as it will ever get)
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You might be able to say that for price per Joule maybe since Joules are units you can divorce conceptually from the fixed startup costs. You can't really divorce Wattage from the startup costs that way. You buy a certain amount of equipment and it provides a certain wattage (depending on average conditions at the location, etc.).
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Oh, did that fly over your head? Did it make a Woooosh when it flew over?
Re:**YAWN** (Score:4, Interesting)
Not really... the point he was making is that the energy is there to be collected, and once the system is installed the maintenance costs are negligible. Many solar installations don't need any maintenance at all beyond keeping the panels clean.
The initial installation costs a lot of money (which is becoming less and less every year), but you can sell any extra electricity you produce back into the grid, and the reduction in your monthly electric bill should be significant enough to make it worth considering. In most cases, the reduction in your bill will be more than enough to cover the cost of the loan to have the panels installed in the first place, and in some cases you'll find yourself in a position where the power company is paying you each month.
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But keeping the panels clean, and replacing them, IS a maintenance cost, as are the replacement of other electrical components and service due to occasional damage. Maintenance costs AREN'T zero and the product has a finite lifetime. There is no such thing as a price per watt of 0 unless you are willing to ignore some of your costs. There are fixed costs and recurring costs and while the recurring cost per watt is 0, the fixed costs are still prohibitive.
Selling excess production back to grid isn't makin
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That would be trivial, if you could find a way to plug it in.
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(indirectly)
http://www.bbc.co.uk/news/business-20003704 [bbc.co.uk]
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Is it clearly cheaper for you in terms of net present value over the long term, or just in absolute outlay of cash?
I don't mean to imply that it's not, I'm just genuinely curious about your situation and if it still holds.
Re:AHWESOME (Score:5, Funny)
I am concerned about the long term effects of taking all that power from the Sun. How long before it starts to shine less, or doesn't keep us in orbit anymore. The whole idea of endangering the longevity of the Sun gives me shivers. Think of our children!
OMFG (Score:2)
OMFG if you weren't replying to me I'd mod you to high heavens. I even have mod points now...disappointing :(
Re:AHWESOME (Score:5, Funny)
This is true. They've used too much solar power and now in some parts of northern scandinavia there is darkness for 3 months of the year.
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photosynthesis (which powers virtually all life on earth) is less than 1% efficient
Wikipedia says it is a bit better than that [wikipedia.org], but in this comparison, we are not taking into account the cost of building the solar panel or the plant, let alone disposal (how long does the solar panel lives?)