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Solar Power Becoming More Affordable
prostoalex writes "With both startups and large companies such as Boeing working on solar power, the technology is becoming more affordable, MIT Technology Review says. Solar power concentrators are all in rage now: 'The thinking behind concentrated solar power is simple. Because energy from the sun, although abundant, is diffuse, generating one gigawatt of power (the size of a typical utility-scale plant) using traditional photovoltaics requires a four-square-mile area of silicon, says Jerry Olson, a research scientist at the National Renewable Energy Laboratory, in Golden, CO. A concentrator system, he says, would replace most of the silicon with plastic or glass lenses or metal reflectors, requiring only as much semiconductor material as it would take to cover an area the size of a typical backyard. And because decreasing the amount of semiconductor needed makes it affordable to use much more efficient types of solar cells, the total footprint of the plant, including the reflectors or lenses, would be only two to two-and-a-half square miles.'"
...are fast approaching. And thanks to nanotech, these panels will be so compact that we'll be able to have solar powered cars that will even run off of moonlight. Once that happens we can kiss the middle east goodbye. True energy independence for ALL!!! Rummy and his cronies can take a hike too. Vote Libratarian!!!! Gun, Girls and solar power all the way woohoo!!!!
-"...bad old ideas look confusingly fresh when they are packaged as technology" - Jaron Lanier (Digital Maoism on Edge.o
This headline can be recycled and reused into perpetuity. Chances are with continuing advancements it will always become more affordable than it was last week, month, year, decade, or century.
But when will it become truly affordable for the masses? That's what most of us want to know. Wake me when it's time to disconnect from the petroleum/nuclear fired grid.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
"would be only two to two-and-a-half square miles."
Two square miles of mirrors and tracking gear? Let's just say that it costs a super cheap 20$ a square foot.
The cost of the mirrors alone would be $1,115,136,000.
One of the big problems with mirrors as lenses is that they have to be cleaned. Just think of the labor costs that would involve. Then let's think of the cost of the land.
Sorry but ONLY!!!!
Interesting but not cheap. Could work in some places like eastern southern California, Nevada, Arizona, and maybe south west Texas.
See my blog http://ilovecookes.blogspot.com/ for light hearted technical information.
Why all the talk of centralized power generation?
:p) energy would a fraction of what it is now.
Solar panels are the way to put power generation into the hands of the people. When I look out at all the rooftops in the area - houses, office buildings, Super S-Marts and their enormous un-covered parking lots, all I can think of is if every one of those surfaces had a single solar panel our energy demands from centralized (corporate
Have we learned nothing from decentralized computing?
How reliable is this? what if we have a cloudy week .. will there be enough current stored? Or what if there is a volcanic event such as Mount Tambora (located in the "Dutch East Indies") erupted back in April 5, 1815? That caused a layer of atmostpheric dust that resulted global extended winter (it even snowed in the Northeast in June).
.. ie, a law that basically tells authorizes designated areas for 'em. Although a referendum may be "unnecessary" .. it would pressure legislators to enable the granting of licenses to build 'em.
My point is that solar is unreliable. And yeah we do have a clean alternative: nuclaer.. May be there should be a national referendum to authorize it
years. One of the major problems of concentrated solar power is the heat - normal photovoltaics would melt. The benefit is that concentrated light also has better efficiency than the normal ~10-22% of normal solar power. One of the traditional ways around the heat problem wasn't to use a photovoltacic as all. An energy farm in Australia uses dishes to focus the light and at the focal point places a stirling engine, with only the heat powering it. Interesting stuff. I hope to have my own workable solar power system power my property one of these days.
Let's see, four square miles of sunlight focused onto my back yard. Conversion efficiency ~30%. Melting point of silicon 1414 deg C.
Unless I've got a backyard the size of Bill Gates, lifetime of new solar plant = one sunrise.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
That's not even enough to go Back To The Future!!! Still, we should be building these en masse right now. They will pay for themselves and after that point it's all free, clean, non-Saudi-dictator-supporting energy.
Regular Meta Moderators are not more likely to get mod points.
"Indeed, if manufacturers can meet the challenges of ramping up production and selling, distributing, and installing the systems, their prices could easily meet prices for electricity from the grid, says solar-industry analyst Michael Rogol, managing director of Photon Consulting, in Aachen, Germany."
I've heard that Photon Consulting is really fast.
"We are all geniuses when we dream"
- E.M. Cioran
Let's try to put the 2nd law of thermodynamics into terms most people can understand.
(1) The 2nd Law of Thermo is a law of entropy, and thus applies to *everything* in our universe. That includes mathematics. (Data compression limits, anyone?) It also includes solar panels.
(2) The limits on solar energy involve limits on transferring power from one form to another. As such, the second law of thermo implies that as you approach a lower-than-100% ideal efficiency, you approach zero power actually transferred.
(3) For an example of ideal efficiency, Carnot Efficiency, which is a function of the input and output thermal temperatures, 100%-100xT1/T2). So that means with two input and output temperatures of 100K and 273K, the ideal efficiency is 63%, and a real engine (eg. electric heat pump) would give less efficiency than that -- maybe 50%.
I truly believe that the #1 reason why distributed power systems like solar, hydrogen, etc, are not taking off are because the big energy companies don't WANT decentralized energy systems - because they can't control the profits as easily.
Take hydrogen. The day someone figures out how to easily produce hydrogen the days of energy monopolies are over - anyone with access to water (or whatever the raw material turns out to be) can do it.
Same with solar. If they got efficient solar panels so you could be energy self-sufficient there are a lot of people in power with a lot of money who no longer would be in control of the show.
Steve
A work that expires before its copyright never enters the public domain and thus enjoys eternal copyright protection.
>One of the big problems with mirrors as lenses is that they have to be cleaned. Just think
>of the labor costs that would involve.
I would think someone would invent little robot cleaners (solar Roombas) that could periodically go out and clean the mirrors and solar cells.
Steve
A work that expires before its copyright never enters the public domain and thus enjoys eternal copyright protection.
Americans vote Democrats control of our government, and suddenly 3 days later solar power could be affordable. When they actually take power on 1/3/2007, will we finally get our goddamn flying cars?
--
make install -not war
What about in summer? The windows can be opened and replaced by screens or shaded.
-b.
I understand the attraction to a direct-to electricity approach has such as low to no maintenance; but it just seems to me that other approaches such as solar boilers and sterling generators are going to have an edge for quite some while. The ability to throw some more sunlight at the target can overcome many mechanical inefficiencies, I think this is like computer upgrades, sometimes you just have to go for it because there will never be an optimal time
Apocalypse Cancelled, Sorry, No Ticket Refunds
That was my first thought on reading this. If you're concentrating the light to a point anyway, why not just shine it on a tube of water and make power with the steam? I haven't looked into which would be more efficient, but I know that solar at this point wastes most of the possible output. If properly done could this not only remove silicon from the equation all together but also improve output?
Does a line appended to your comment give your post meaning in and of itself, or only in relation to those without?
Is this at all related to what Energy Innovations has been doing?
ha ha fooled you...sort-of. I have a backyard garden, which uses solar energy to produce food six months a year. My sorrel becomes edible in April/May and my potatoes are harvested in September/October. ...and I save a couple of hundred dollars by NOT buying from Safeway supermarkets.
And it only costs me about $10 a year. I compost everything, don't use fertilizer, and only grow drought-hardy varieties that can grow with the amount of rain that my area provides.
Slashdot Burying Stories About Slashdot Media Owned
One thing I really wish would happen is that the efficiency of thermovoltaic technology could somehow be improved... Think about how much energy is wasted as heat; eventually all of it, I suppose. I actually heat my bedroom in the winter with my PC. When I read about large scale solar facilities, I can't help but wonder at the losses in heat that are going on there. There are more efficient ways of utilizing solar power right now anyway: http://www.stirlingenergy.com/ comes to mind... and they work pretty well. It would be nice, however, to move the technology to solid state like we have with photovoltaic cells; That way we could apply them to things like brake shoes on cars, the condensers on refrigerators and air conditioners, etc... -Photovoltaic paint has been invented, but is not realistic yet. I think that's where the future is: Objects that need electricity should become more efficient, and should have photo/thermovoltaic technology built right into them.
-ubuntu others as you would have others ubuntu you.
Doing it so that it's INEXPENSIVE and easy...THAT is the real challenge.
Chas - The one, the only.
THANK GOD!!!
Hydrogen will always take more energy to produce than it generates. Thus, Hydrogen might become a better sorce of stored energy (and replace gasoline) but it can never be used for power plants. Solar does have the potential to eliminate the need for power companies, though.
You are reading a copy of my copyrighted post.
What do Carrots have to do with solar power? Are you taking about the 100% efficiency of photosynthesis? Tell me more...
-"...bad old ideas look confusingly fresh when they are packaged as technology" - Jaron Lanier (Digital Maoism on Edge.o
Just think ... to save even more space, we can use several layers of reflectors ... oh, wait ....
Part of the problem is the durability of these panels. The affordable ones have relatively short lifespans (under 10 years, and at that point, still haven't saved enough to justify their cost). The ones that ARE durable enough to last longer are hideously expensive, and not the sort of thing most people have the cash for.
Also, there's the fact that solar power is not a viable solution everywhere in the world. Sure, in Arizona, California, etc, it is a wonderful "free energy" thing.
In Pacific Northwest, the northern Midwest, etc, especially during the winter months, solar power is a complete non-option.
Chas - The one, the only.
THANK GOD!!!
"Let's try to put the 2nd law of thermodynamics into terms most people can understand.
"
You failed....
""I don't see an obvious biosynthetic pathway from allicin (CH2=CHCH2SS(=O)CH2CH=CH2)to isothiocyanates (R-N=C=S) ""
But the demand for silicon in the creation of computers, has kept the price high. It is an ironic, catch 22 situation.
But there is hope. If we ever switch to non-silicon based computers, the price of pure silicon is expected to drop to a level low enough to make cheap solar panels a reality.
excitingthingstodo.blogspot.com
Concentrating Solar Thermal Power plants have been in successful operation for decades in California. Note how the article avoids any mention of them, instead comparing Concentrating Solar PV with non-concentrating Si-PV. Note also how proponents of solar PV (and of wind turbines) always "forget" to mention the biggest drawback, which is the fact that they only produce electricity when the sun shines or the wind blows. CSTP differs fundamentally in that the energy is collected in the form of high temperature heat, which can be temporarily stored by various methods. This means that the electricity production can be fully controlled and that production can be sustained 24 hours a day. The largest single CSTP plant has been turning out 80MW for almost 20 years now. Low fossil fuel prices made further development temporarily unattractive but the rate of development and deployment is picking up again for obvious reasons. Once the learning curve kicks in the price of CSTP will gradually go from the current 12 c/kWh to something like 5 c/kWh. Include the cost of all the back-up power needed for intermittent solar-PV and wind power and it is obvious that they will never be able to compete with CSTP in time to solve the upcoming energy crisis.
Actually, a heat pump is a bad example, since you're putting energy in to move heat, not moving heat and getting energy out. With an engine, the amount of heat moved always has to be greater than energy out. Same with a heat pump - you actually can move more heat energy than you put power in. Hence coefficients of performance greater than 1.
-b.
Your model (a heat engine) doesn't really work for solar cells, although you are certainly correct that 100% efficiencies are unobtainable.u ll-spectrum-solar-cell.html
In solar cells, the point is that photons excite valence electrons across a barrier, giving them enough energy to create a current. There isn't really a classical analogy for this effect.
There's a limited discussion of solar cell efficiencies here, although it doesn't talk much about the underlying physics:
http://www.lbl.gov/Science-Articles/Archive/MSD-f
The upshot is, cells of a single type of material can only get up to about 30% efficiency, but we can stick several materials together to get past that barrier.
I thought solar power was FREE?!?!
Count the hours you spend gardening every year, including shopping for supplies.
Multiply that by your net income after taxes for a part-time gig using your skill-set.
Add that to your $10/year actual cost.
Then subtract the cost of groceries and the time you would spend grocery-shopping.
Subtract the value of the health benefits from eating your own food.
Subtract the value of the health benefits from doing manual labor outdoors.
Subtract the value of the intangible benefits you get from a hobby you enjoy.
Add and subtract anything else I forgot.
That is your real cost. Not $10. Not counting them or the health benefits, your costs are probably $thousands. Counting the intangibles, you are probably "making a profit."
Knowledge is how to play a game, intelligence is how to win, wisdom is knowing what game to play.
Figure out the cost of a solar reflector, both for fixed position and steerable ones. One strong enough to survive wind and rain.
Then figure out the cost of maintenance.
Then figure out how to convert this focused sunlight into electricity. Hint: photovoltaic cells won't do it.
Then figure out how much you'll have to pay in interest every yearto borrow that amount of money.
Compare with the wholesale value of thwe generated electricity.
You're likely to find the electricity cannot even pay for the interest cost.
I've worked a lot with photovoltaics. They're really cool, but I recognize their limitations for utility-scale power generation. The primary limitation is that silicon-based photovoltaics currently convert only 10-23% or so of the incident solar power into useful electricity. Silicon solar cells cannot convert infrared light to electricity - the photons have too little energy. Higher energy photons (visible and UV light) are poorly utilized - a solar cell will get the same energy output from a red photon as a blue one, despite the fact that the blue photon has higher energy. Solar cells aren't very reflective (by design), so most of the remainder of the unconverted sunlight becomes heat in the cell.
You can get higher efficiencies by going to other chemistries, like GaAs, and by layering different chemistries on top of one another. These are not cost effective, and won't ever be able to get above, say, 50% efficiency.
But solar energy is not limited solely to photovoltaics. Probably the best way to use solar energy is solar thermal - capture all that 1000 W/m^2 of incident sunlight as heat. It can be used to heat a fluid up to fantastic temperatures, which can drive turbines, etc. This is the principle behind Solar One, Two, and Tres and the Nevada Solar One plants. These are, however, demonstration plants, not utility scale.
The other major kind of solar energy is biomass. Photosynthesis is a pretty good way to capture sunlight and make it do something useful. Plants have had a looong time to get good at making use of sunlight, which we use to our benefit in many ways. When cellulosic ethanol comes around, you'll probably make better use of sunlight by planting crops and building a solar power station.
Two passive water heating panels have cut our electricity bill by 30-40% this year. Three panels, about 2m x 1.5x each, 20 year life span IIRC. Cost £4-£5K to buy & install, will pay for themselves in five or six years (looking at it purely financially - of course part of the motivation for doing this is to reduce our carbon footprint.) We've also installed a lot of very very expensive double glazing - our house isn't a listed building (though it is three hundred years old in parts) but we still didn't want to wreck the elevation with crappy PVC rubbish; instead we've got individually hand-made window frames with the correct small-sized panes. Actually it's improved the look quite a lot, as we got to rip out a lot of hideous late 60s "minimalist" style T frames :)
Everything I needed to know about life, I learnt from Blake's Seven
I searched on 'mirror cost "four square feet" solar' and the Google summary for the second hit showed a cost of $5/sq. foot. That's an upper bound, as I'm sure economy of scale would kick in. So, for 2.5 square miles or 70 million square feet, that's about $350 million dollars. As others have said, not bad for a 1GW power plant.
Ben Hocking
Need a professional organizer?
We still need better inverters. These are the devices that convert DC into AC for use by common appliances and to power your home. The ones designed for home operation are wimpy, apparently intended for a home where people trim back on using energy in electrical form, already. The ones designed specifically for the wide range of voltage change from photovoltaic arrays/strings are big expensive commercial units intended for selling power to utilities, or for the utilities to buy for themselves (they shut down and night and can't run from batteries very well).
I want to reduce my carbon footprint with emphasis on reducing use of fossil fuels in particular. I'm less concerned about burning wood than I am about burning gas (natural gas or liquified propane). So I'd like to run my kitchen from solar and wind generated electricity. That means I need on the order of 12 kW of power just for potential peak cooking. Add another 2 kW for microwave. Add some more watts for the blender, coffee maker, refrigerator, etc. It adds up.
One of the big makers of home inverters for general DC conversion (e.g. batteries charged from various sources) is Xantrex. But their largest unit in this market segment is only 5500 watts. Two of the North American 120 volt units can be "stacked" to get 120/240 volts, but that's still only 11 kW. Some other companies offer as much as 6000 watts in a single unit, and do not even appear to be "stackable". What we need is a line of inverters, each specifically designed for the various world power systems so people can use their common domestic appliances, but with a variety of power levels in many steps all the way up to 100 kW or more.
There is one technical issue with inverters, and this is not something that is easy to solve. It also exists to some extent with small generators. That issue is that under short circuit conditions, they produce only barely (about 15%) more current than their design rating. To many this might seem like a good thing. But it actually is a hazard. The reason is because short circuits will fail to trip home branch circuit breakers. A common circuit breaker rated for say 15 amps generally won't trip for a while under a 20 amp load, until its thermal element gets quite warm. For an instantaneous trip using its magnetic element, the current has to be significantly higher, like 150 amps or more. Utility power through a transformer can easily deliver several hundred amps under a short circuit condition. With hefty power lines and transformers these days, if you are close to the transformer, you could even get several thousand amps real close to the breaker panel. This is why if you have ever shorted out a power circuit, you get a nasty *POP*. That's some big amps followed by the breaker cutting the circuit off.
I've found some inverters that have circuit breakers on the output AC side that are rated at a higher amperage than the maximum they could deliver under a short circuit condition. In other words, short out the AC right after the circuit breaker and you can't even get enough juice to cause the breaker to kick off. The inverter itself may very well detect the overload and soon shut off.
Many appliances may not even work under this low fault current condition. Big motors can have trouble getting started if they can't pull 3 to 5 times the normal amperage for part or all of a second. And even some electronics wants that much power or more when you turn them on to charge up the power supply capacitors. One relative has found that his big screen TV, although using way less than the 5000 watts his generator can produce, just won't even turn on under the generator. When he turns it on with utility power, all the lights in the house dim significantly for just an instant as the monster sucks a huge number of amps.
Ultimately, if you want to power you whole home with AC power through an inverter that converts the DC stored in your batteries charged up from your solar and/or wind power sources, you'll need some hefty
now we need to go OSS in diesel cars
There was a good Wired Article on a startup company developing a solar cell product using a concentrator back in June of 2005, which included good coverage of the reasons behind using concentrators, as they're much cheaper than silicon, and solar cells can handle much more intense light than plain sunlight.
Can anyone tell me how to set my sig on Slashdot?
Finally - this can only mean that Halliburton and Bechtel decided to lower the price of photons!
"Win treats sysadmins better than users. Mac treats users better than sysadmins. Linux treats everyone like sysadmins."
But I used to work for a solar photovoltaic system installer, and I was very well-versed with the prices for the common residential customer, at least in California, and I have somewhat kept up to date with what's going on in the industry.
Back in 2003, a 2.5 kw AC system cost about $10k to $12k to install, depending on various conditions, such the type of roof. Prices usually scale proportionally as you increase the size of the system. Nowadays, I hear the figure is about $16k to $18k.
Why the increase of the prices?
One of the biggest factors is that, at least in California, the CEC rebate (for customers of most power utility companies) was $4.50 per watt back around ~2002, going down by twenty to fifty cents every six months. It used to cover more than half the cost of any installation up to 30 kW.
These days it's $2.60 per watt. While solar panel prices have gone down a bit, it no longer covers more than half the cost.
Other factors resulting in higher prices: the value of the dollar has gone down in the last couple years, and since many major photovoltaic panel manufacturers (ie: sharp, kyocera) and inverter manufacturers(Sunny Boy) are foreign, that results in higher prices here. Also, due to worldwide demand of silicon in the last couple years, there has actually been a shortage of panels for the company I used to work with. (though I don't expect the shortage to last forever)
Beyond that, the labor part of the installation usually significantly adds to the bill -- my guess, probably around $5k for a typical residential installation of 2.5kW, depending on the contractor.
That's not to discourage people from getting a solar photovoltaic system installed. Technology and mass production will always result in a downward force on prices. Even if solar photovoltaic systems increase in price, it's really the cost per watt from the local energy utility company in comparison to the cost of solar installations that customers consider. And energy utility prices in California are some of the highest in the country, and mostly continue to increase.
The manufacturers of rubber gloves will make a fortune!
Prov 9:8 Do not rebuke mockers or they will hate you; rebuke the wise and they will love you.
There has to be a HUGE stockpile of old AOL CDs still out there, lets put them to good use.
The part I'm confused is : why haven't I seen yet a combined system. I might be wrong here, but PV cells have an efficiency of about 20% (I might be overly optimistic here). So I guess the "other 80%" is lost in 'waste-heat' (those panels get rather hot I'm told, which actually makes them less efficient). Why isn't the remaining 80% used to heat water. The water can be used for either house-hold purposes (heating/showering/etc..) or drive something like a Sterling engine to generate additional energy...
(In winter the PV might still produce some watts, while it wouldn't be able to heat the water sufficiently to keep the Sterling engine going.. although, by design, a Sterling engine should be able to run on even a small delta-T)
If there is one thing to be learned on slashdot, it has to be sarcasm.
These concentrating lenses do not need to be very complex at all. In fact they don't even need spherical curvature at all. What they need are angles. That effectively makes a crude, but adequate, Fresnel lens. With flat surfaces, they are also cheaper to make.
The original Fresnel lens design for lighthouses needed to work with a very small focal point, the light source, and beam that light very straight. Thus it needed that spherical curvature. Even in its varies steps or layers, that sperical curvature still exists. Solar cells, however, do not need this.
Suppose you have a small solar cell module that measures 10cm x 10cm. Place it at the center of the back of a larger 50cm x 50cm box with the front aimed directly at the sun. Over the front of the box place a 5x5 grid of 25 openings, each the size of the solar cell. In the center, only a flat piece of plastic is needed. Outward from the center, a piece of plastic that is angled like a thin prism would be placed to bend the light at the necessary angle to hit the solar cell at the back. You'll have to figure out the right angle based on how deep the box is. But you will only need to have just a few different kinds of angles to complete the construction and concentrate almost 25 times the light onto the solar cell. Solar cells even operate more efficiently on concentrated light levels.
The box will need to track the sun to keep the various angled beams focused on the solar cell.
An alternative design is a box that is wider in one dimension and has open sides in the other. Stack multiple boxes with the wider dimension vertical so their open sides mate with each other. Tilt the stack to the angle of the sun's path and aim it for about the noon sun position. Then the morning and afternoon sun will be at an angle that lens light from one of these narrow boxes go through the mated openings and hit the solar cells of the adjacent box. You only lose what would be at the ends but you don't have to set up a steering mechanism.
Variations of these designs use mirrors instead of lenses to concentrate light. I personally favor the mirror designs using non-imaging reflective topologies. The same methods are also used for water heating.
Also consider using a water heat collector behind the solar cells. They do get hot (they aren't 100% efficient, so the energy is wasted somewhere).
now we need to go OSS in diesel cars
Wow, that's just 3.025 square miles to generate 1.21 gigawatts.
If moderation could change anything, it would be illegal.
These guys aren't too clever to bring this up during such dark seasons for most of us in the northern hemisphere. Power from the sun isn't really what's on my mind this time of the year.
From my recollection, cells that are used with concentrators tend to brown, deteriorate, and lose production capacity much faster than those that aren't. That hasn't changed, has it?
steve
Oh, you're not stuck, you're just unable to let go of the onion rings.
Does this mean they've finally found a use for Nevada?
Do what you can, with what you have, where you are.
You forget the five Solar Thermal plants at Kramer Junction which together produce 165 MW. SEGS III - VII, as they are called, have been in commercial operation for around twenty years now. These are definitely utility scale plants, not demonstration plants.
The real problems behind solar power is not the surface of the plant, but the variability of solar output.
Suppose that your Country produces 100% of its energy from solar.
What to do the days whithout sun ?
The options are:
1) storing the energy
2) using other source of energy
3) importing the energy needed from other countries
4) dying
Each of these solution is not free, nor it is simple.
For example if country A imports its energy from B when it is cloudy over A, and B imports its energy from A when it is cloudy over B,both A and B need to produce more energy than needed by themselves!
Storing the energy it is nor cheap nor efficient, and using other sources of power just when it is cloudy is stupid from the economical point of view (using a plant just 1000 hours per year means that the cost of energy produced in these hours is high).
So if you want to replace 1GW produced from oil with solar power, you need to produce more than 1 GW !
(I am sorry for the low level of my english, but I have studied it as a second lenguage more than 10 years ago at school! )
He might have jumped the tech track, but he's right in that it is already happenning. I've been tracking (no pun intended) the solar concentrator race here if you'd like to see the players in bringing these products to market:
/ 1089
http://www.dailykos.com/storyonly/2006/10/8/15152
Someone had to do it.
why haven't I seen yet a combined system
Because it doesn't make sense economically. Yes, a combined system would save on roof space and mounting equipment, and would waste less of the sunlight striking it. But solar is so expensive that only millionaires can afford to cover their entire roof with solar heat or electricity, and combined systems cost even more.
I have both solar PV (nine BP panels) and solar heating (european tubes filled with glycol) on my roof, I'm waiting for approvals and final plumbing. The two systems are installed by different trades with different mounting frames and different hookups to your house.
The Holy Grail for all solar energy systems is to be cheap and efficient enough that any company or homeowner with some spare cash and roof space installs or adds on to one. It would be amazing if a combined heat and electric system reached that point, but I think dedicated systems will get there first. A solar electric system using a concentrator has to deal with overheating, so maybe it'll prove economical to do something useful with the waste heat.
Read all the Energy Innovations Technology pages for insights into the difficulties of making a concentrator system reach that Holy Grail, including a Stirling engine design
=S
A bit off topic, but...
The first thing I thought when I saw "solar concentrators" was the Clive Cussler novel "Sahara", published in 1992 (later made into a move that, while not bad on its own, missed 80% of the plot... but whatcha gonna do in 110 minutes?).
In the novel, the big bad guy uses a huge solar concentrator system in the desert in Mali (quite different from the concentrator system in the movie) to power an incinerator to destroy toxic waste.
So the idea has been around for a while. It will be good to see it expand as sustainability becomes not just fashionable, but profitable.
Find environmentally and socially responsible products on http://buy-right.net
See Quantum Dots.
In a paper published in the May 2004 issue of Physical Review Letters a team from Los Alamos National Laboratory found that quantum dots produce as many as three electrons from one high energy photon of sunlight. When today's photovoltaic solar cells absorb a photon of sunlight, the energy gets converted to at most one electron, and the rest is lost as heat. This could boost the efficiency of panels produced in research labs from today's 20-30% to 42%. This work was reproduced one year later by an NREL team.
Poke around the net some looking for quantum dot solar panels. Lots more stuff out there, and it's all pretty exciting. The end result may be a quantum dot paint you simply slop on your roof every couple of years.
Weaselmancer
rediculous.
Um.... thats ALWAYS what you are doing.
I once heard a mechanic say "You can just think of an engine as a glorified air pump" (a really dirty one)
The point is you just have to change how your looking at it. To see a heat pump as a generator, look at hot air on one side as fuel being burned (with colder air being the exhaust output) and hot air on the other side as the output energy.
Actually it has 2 fuels... the electricity comming in too. So it burns electricity and hot air, and makes hot air on the other side.
An air conditioner is just a heat pump where you hang out inside the "spent fuel tank". Its kind of like an engine with no alternator so it needs an external power source to spark the gas. And instead of hooking up a cam shaft, transmissions and wheels, you just pump the exhaust into the room to keep warm (finding the problems with that plan is left as an exercise to the reader)
-Steve
"I opened my eyes, and everything went dark again"
The problem is that power is stored in the chemical bonds between carbon, hydrogen, and oxygen atoms in fossil fuels.
In my senior year at a Southern Californian university back in '96, I took a mechanical engineering class which basically let you choose a project (approved by the instructor) and work in teams to present a solution/product. One of the projects was for a local solar plant that used acres of these long, acutated curved mirrors to reflect light to a tower that held a steam-powered generator. Their problem? The mirrors lost significant reflectivity due to dust, and they had no good way of cleaning these large curved mirrors . When dirty, the loss was so great that it was often more cost-effective for them to run the boiler off of natural gas than to use the mirrors. And the huge custom mirrors were expensive to replace. In fact, by that point they had stopped replacing broken mirrors and operated the remaining mirrors only on the sunniest days.
I really hope they have solved the dust problem with these new photovoltaics. When these are deployed, efficiency under laboratory conditions won't count.
Energy Innovations has tried Fresnel and is working on mechanically steered 5x5 set of mirrors.
Your box sounds promising but a grid of them requires an elaborate supporting frame? The Energy Innovations Sunflower 250 lies flat on the roof. Your water heat collector adds expense.
=S
Aren't they the party that proposes setting national policy by a daily horoscope? That would make the United States a Cancer...
(Stop that snickering, you in the back!)
Strike while the irony is hot! -- The Freethinker
>Solar Power Becoming More Affordable
Err, solar power is free, actually. Last time I checked, Mr. Sun wasn't charging for his rays. It's the conversion that costs....
joab
The issue is still watts/$, but there's no reason that the $ should include paying for all that land, and the corresponding social, political and environmental costs. It doesn't matter if they the panels are so inefficient that it would take the equivalent of, say, 16 square miles to generate a kilowatt, if we can get that area for nearly free on existing structures.
This approach also brings the benefits of decentralized power generation, such as avoiding transmission losses. But I just like it because it's the zergling rush of electricity generation.
The problem with solar power is never the efficiency of the collection system but rather with the fact that the power cannot used on demand. Without a staggeringly efficient means of storing the power, solar power will remain useless for all serious generation. There isn't a single factory, communication system, transportation system or any other important part of our civilization that runs off solar power and baring currently unforeseen breakthroughs in storage technology there never will be. We simply can't run a modern civilization off a power source that randomly disappears. Every solar power installation requires a 100% non-solar redundant system to take up the slack when the solar goes off line. Factor that cost in and solar power becomes an economic joke.
Solar power isn't a solution. Its a distraction. It lets politicians and others pretend that they are doing something about serious energy questions instead of making unpopular, real-world choices.
Because it'd ruin their argument.
Fill in your four or five-letter word of wisdom here _ _ _ _ _.
Actually, Solar Power is already feasible. A study that was commissioned by the European Union in 1995 tasked the European Photovoltaic Industry Association to determine what it would take to make PV electricity cost competitive with traditional power. BP Solar was the lead investigating company and reported to the EU in 1997 that they could make PV comparable if they built a 500MWp plant.
As a matter of fact, one of the newest players in the renewable energy market - The Citizenre Corporation - is offering Solar Power to all American homes at virtually no cost to the home owners. The Program, called REnU - which stands for Residential Energy Unit - represents the most forward-thinking initiative toward energy independence and preservation of the environment.
We might actually go down the history books as the last generation who burned anything to make a watt.
They already do it in Missouri. Check out the Taum Sauk pumped storage plant. Pump the water up the hill during the night when there's excess power and dump it back through some turbines during the day when you need it.
The best thing about solar, though, is that peak demand is in the middle of the day...when solar is generating the most it can. So you just flip the system around. Use storage methods like on Taum Sauk to stockpile nighttime power to pick up the solar shortfall then.
The part I'm confused is : why haven't I seen yet a combined system.
There has been plenty of experimentation with such systems, but the benefit to the PV (which works better when it's cooler) and the quality of the heat extracted (which is basically lukewarm) has not really made it cost-effective. You get a boost of about 3-4% in electrical power output, but the water is really only useful if you use the PV panels as pre-heaters and can move the water to another heating system to finish the job before it loses the heat gained from the PV. Thus far it has been more economical to keep the two systems separated.
That said, a company called Solarwall recently announced a combined PV/air heating system that it put together. No word on economics or commercial plans, though.
I forgot the exact physics of this but I've read it somewhere too that due to the excitation of the valence electrons and promoting them, the theoretical maximum efficiency of the conventional solar cells is capped at 50%.
_ cells
According to wikipedia, dye-sensitized solar cells have a theoretical max of ~33%. I'm not too sure about the physics of this though but I was pretty excited about this a few years ago as I thought that the theoretical max of such cells is 100% (less the inefficiency due to impedance) http://en.wikipedia.org/wiki/Dye-sensitized_solar
You mentioned this greenhouse-connected-to-house and its savings a couple times. Can you recommend any references or links? (how to build, estimates of costs and of energy saved, etc) Thanks!
Of course I will Google but it sounds like you already know what you are talking about.
>That's not going to happen. The most plentiful source of hydrogen on the planet is water.
>No one is going to be able to figure out a system that uses less engerdy to split the molecules
>than you get in return by burning the hydrogen or using it in fuel cells.
Man, there are a shit-load of things we buy and use every day that consumed more energy in their making than I get out of it in the end product.
My reply to this is a big fat "so what"!
Let's say it takes 100 times as much energy to make a volume of hydrogen than I get when I burn it in my car (I'm pulling this number out of my ass).
If the hydrogen is cheap, compared to, say, gasoline, who cares how efficient it is?
OK, so we need a nuclear reactor or giant solar concentrators to crack the water into hydrogen and oxygen. As long as the economies of scale make the end product (they hydrogen) cheap, I don't really care how inefficient the process is to produce it.
The trick is to find a cost-effective, hopefully renewable way to produce hydrogen. Efficiency is secondary.
A work that expires before its copyright never enters the public domain and thus enjoys eternal copyright protection.
I installed a solar/inverter/battery system in my cabin this year, demoting my pair of propane generators to backup and cloudy day devices. One thing I found during the selection process was that some of the inverter companies are just coasting. They have a product that everyone in the field is familiar with and they just sell them. You might want to check some of the newer players. I went with OutBack Power Systems. They have a solidly engineered modern design that can make a geek drool.
Are we there yet with solar? No, but I think the tipping point is coming. The fact that there is some serious private investment in solar is the biggest sign. Some businesses are getting some massive investment based on new patents that threaten to bring the price of solar cells way down. Stirling generators are just superb for plopping down on your roof.
I always wonder how much it would cost to lease people's roofs. Basically, it's like a whole bunch of land that you could put solar generators on, produce power, and sell it. Most of these systems are supposed to generate more power than an average house uses, right? So, in exchange for a portion of the power, Joe- and Jane-homeowner lease you their roof, you pay for a fixed proportion of their monthly wattage, and you get to sell the rest to local commerce and industry. Because you operate at a large scale, you can make the generators, batteries, and electrician-hours much more affordable than the homeowners can. Everyone gets cheaper power, roofs look more interesting, industry benefits because of cheap local power, etc.
Building solar power plants seems to be missing the point -- solar's ability to be widely distributed should be taken advantage of.
Which is to say that a cloudy day no longer needs to shut down a solar power plant which uses more expensive cell technology, which the article mentioned it would.
-FL
Funny the GP does not seem to realize that this is a techy forum, not a place where you successfully instill FUD with the prospect of a little dust and grit. Were the manpower for the occasional cleaning on existing facilities really so expensive, they'd just install automatic wipers. (As it is, some farms simply turn the panels upside-down at night to reduce the need for cleaning -- that's when most of the dust settles.)
$20/square foot for just tracking gear -- feh. Maybe for joe-six-panel's one-off purchase. When you are buying for a 1000+ panel farm, you get better pricing than that.
Someone had to do it.
How much power gets used by computers, TVs, air conditioners, and other appliances that operate mostly during the day? What about industry? Commerce? Office towers use most of their power during the day. Many factories shut down at night.
Daytime is when most electricity gets used. That's part of the reason solar makes so much sense once it is affordable.
One of the better solutions I've seen used is simply to own equipment which runs on DC. Most of the items I use day to day need rectifiers anyway. The only really difficult items seem to be washer/driers and refrigerators, which in the example house I saw, needed broader thinking to solve, but were solved nonetheless.
One nice thing about being in a house wired for 12 volts DC was the lack of AC 'Humm'. It was really relaxing; like being out in the woods or something. A music prof at the local university nodded and informed me that wall socket power is indeed something you can detect with the normal senses.
-FL
What? You've never heard of the were-car?
AKA the "Wolfs Wagon".
(runs, ducks , hides)
putting the 'B' in LGBTQ+
Carnot only deals with converting heat to motion, not necessarily with converting radiation to electricity...
But, still, your idea is right - it's unlikely that we'll ever get past - or maybe even TO - 50% on solar cells. That would still be a HUGE deal, as current cells are something like 12% or 13%, if I recall.
There was some hubbub a while back about indium nitride potentially reaching an efficiency of 50% for two layers, and up to 70% with more layers - but it's been years, and I haven't heard anything else about it. My guess would be that either they weren't able to make it work, or weren't able to get the crystals that they would need to grow together.
Oh, you're not stuck, you're just unable to let go of the onion rings.
I've checked out more than a dozen companies for inverters. The problem with the Outback models is they don't work in series beyond just 2 units. Otherwise it takes a transformer to get the correct voltage system (120/240 split phase) that everything else is designed for. The European models for Europeans works out better because it delivers the exact voltage needed, and can be paralleled to several units. Oddly, it might actually work out better to go with the 230 volt 50 Hz units and just buy 50 Hz stuff where the frequency is important. Another disadvantage of these is they use a lower battery voltage.
Do you know of an inverter that can take 120 volts or 240 volts DC input and produce a split single phase 120/240 volt 60 Hz sine wave AC output with a 30 kW / 40 kVA (power factor 0.75) rating?
now we need to go OSS in diesel cars
Until that changes, intermittent renewables are going to be a peripheral source of energy, and a distraction in the main game of cutting greenhouse emissions (which will more than likely be energy efficiency, geosequestration, and nuclear power).
Any sufficiently advanced technology is indistinguishable from a rigged demo
--Andy Finkel (J. Klass?)
What few people realize is how much the price of electricity varies. So go get your utility bill. Call the nearest solar energy installation guys. You may find that it's profitable RIGHT NOW to put solar cells on your roof!
Depending on circumstances you can have a payback period as short as 7 years for a solar power system. For a few it's even sooner, especially those who build off the grid.
FalconShould there be a Law?
The average insolation for the desert American southwest is over 10 hours a day. See http://rredc.nrel.gov/solar/old_data/nsrdb/redbook /atlas/ and select Average, Annual, Two Axis Tracking Flat Plate. Now you have $1.2M a day or $438M a year. Although a 4.5 year payback is not what most businessmen would like to see, the power industry thinks long-term by necessity, and this looks reasonable.
Contribute to civilization: ari.aynrand.org/donate
Back in 2003, a 2.5 kw AC system cost about $10k to $12k to install, depending on various conditions, such the type of roof. Prices usually scale proportionally as you increase the size of the system. Nowadays, I hear the figure is about $16k to $18k.
This is true for silicon PV cells. Nanosolar will be mass-producing a 10'x14' (~3m by ~4m) 2.6Kw panel for an installer price of $2500, about half what the silicon panels run. Their factory is set up to output 480MW of capacity per year, with a total construction cost of around $100million US (about 1/10th what a older-tech scale plant would run). This should do a really good job of helping out w/ electric generation in the 'States...
Let's take it one step or maybe a few leaps further, how about incorporating wind power into your intelligent grasp of surface area. How can we make it just as cool to put up a solar powered Christmas display as a wind powered one, granted the overall footprint of our product needs to be considered?
What I see is possibly...what you are pointing out is that there are many areas not considered in the standard approach to profitability in solar.
WTF did you just say? Does this have something to do with Star Trek, Scotty, and "you can't change the laws of Physics?"
Horns are really just a broken halo.
Has anyone calculated the square miles of unused rooftops in the US? And if they were all covered with solar panels how many fusion reactors we would need? (heh)
Yes, that is true. However, there is always sunlight SOMEWHERE on the planet, and with a highly efficient power grid we could go solar without storage. The efficiencies of today's power grid though are of course ludicrously inadequate. Maybe if we discover some kind of room temperature super conductor that is cheap and abundant... :D
rhY
I hold very few opinions. I hold information based on observation and fact. If you wish to disagree, please use facts.
why haven't I seen yet a combined system.
Couple years back the was an article in EE Times about a Swiss(?) company working on something like this in Quatar(?). Memory is hazy here, but the idea was that there was a certain amount of concentration, PV cells were used and water-cooled. The water-heating power was not used for power generation, though, but to facilitate evaporation (which cools splendidly) in a desalination process cycle. In essence you put sea water and sunlight in (both of which southern Arabia has a lot of) and get power and fresh water out.
At the time they were writing about that, the whole thing existed on paper only and they had just started laying pipes and such. I haven't heard about it since and don't know what happened.
We're all born with nothing.
If you die in debt, you're ahead.
...it wont matter as regards your wallet. Centralized power run by huge corporations for profit means you will continually rent their infrastructure and never get it paid off. Never. Youl be paying those gents (say you start paying your own bills at roughly 20 years od for this general example) for 50 or 60 or 70 years maybe. Does this seem like such a deal from them now, a "smart business decision"? Think about it. You will be making someone elses luxury car payments for them in perpetuity, exactly as you are now with any other power company delivered electricity. You dont have any long term pricing contract guarantee either. The way to go with solar power is DO IT YOURSELF, get it paid off, the sooner the better, then you are insulated-pun intended-from future price shocks and corporate and political shenanigans, and you know they will always be there, dont you?.
Do you like computers, find them interesting and useful? Do you rent them, or buy them/build them? You can rent them you know, so why dont you? Oh, thats stupid? I agree. Are you planning on using electricity..forever? Yes? Why do you want to "invest" in renting the infrastructure, paying a premium, agreeing to no pricing contract, when you can own it? Too expensive? Prove your way by renting is better and cheaper into the future (when you still will be wanting electricity), show us a link to your 20 year pricing contract you have with the local utility then.
No average joe can float $5000-8000 for a basic solar install that will pay back in 10 years saving few dollars here and there.
This "pay back in X years" nonsense has got to stop. Solar power systems are an investment, and the correct way to compare investments is to use the annual ROI (return on investment), and not "how quickly does it pay for itself?" Ever ask yourself how quickly your AAPL shares pay for themselves? Of course not. That would be stupid.
In California, un-subsidized solar returns in the neighborhood of 5-7% per year, and with the state subsidies it's 8-15%. (The best ROI comes when you size your system just large enough to lop off the most expensive kWh tiers, instead of trying to offset all your energy use.) If you know of any other ultra-low-risk with ROIs this high, please share. The solar ROI is generally high enough that you can roll the cost of the system into your mortgage and instantly improve your cashflow.
Sounds like this would be a good fit with the Solar Tower.
You only have to pay armed guards for the ashes for 184000 years so that Osama can't get a sackful.
Why is it that people suddenly get pessimistic about our ability to reliably get off this rock whenever nuclear fuel storage is brought up?
I swear some people argue in one article that the space elevator will be done by 2040 then in another that we need to protect the AI's from nuclear waste.
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
>We can get hydrogen from fossil fuels, but that still does not mean that energy monopolies are over.
Yeah, until someone delivers electricity to my home so cheap that in-home or in-neighborhood electrolysis is cheap.
Or until someone invents an enzyme you can buy at WalMart next to the Rid-X for your septic tank that converts your lawn clippings into ethanol.
A work that expires before its copyright never enters the public domain and thus enjoys eternal copyright protection.
It seem that while costs are slowly coming down for solar power, the more important factor that is making solar more competitive is that the cost of fossil fuels is rising. Just look at this quote from the above article:
..."
"...
"We have been able to negotiate a price that is competitive with electricity generated from fossil fuels," Avery said. "We used to pay a 10, 20 or even 30 percent premium for renewables in the past."
At least a part of that shrinking differential is because of the soaring cost of fossil fuels, in particular natural gas. The cost of natural gas, the primary fuel generating electricity in California, has more than doubled in the past year.
Woopty Doo Basil, what does it all mean?!