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DARPA Awards $53 Million for Solar Power Research
mygadgetbox writes "Defense Advanced Research Projects Agency (DARPA) will be giving a consortium led by the University of Delaware nearly $53 million in funding to more than double the efficiency of terrestrial solar cells within the next 50 months. DARPA wants the consortium to develop and produce 1,000 Very High Efficiency Solar Cell (VHESC) prototypes that are affordable and that operate at efficiencies of at least 50 percent. The goal is to create solar cells that operate at about 54 percent efficiency in the laboratory and 50 percent in production."
We spent two decades wasting time trying to improve the energy efficiency of solar cells. The energy efficiency isn't what matters - it is the cost efficiency! If you are using solar cells as supplemental power to a house (their most effective application), then doubling the energy efficiency of the panel just means you get to use a smaller panel. Who cares - you have a whole roof's worth of space up there. Whereas if you get the price down, then you will decrease the amount of time it takes to pay off the cost of the cells, making it worthwhile to include them in more homes. And for other uses - cars, power plants, even if we had 50% efficient cells they still wouldn't generate enough power to be much use.
I have been getting excited about some of the recent research that is making progress towards less costly, cleaner (to produce and dispose) solar cells. I guess if you are the military, and price is not an issue than this DARPA research is usefull. They need to find some way to power all this new electronics equipment that soldiers are carrying. But it is improvements in cost efficiency that will really make a difference in real world.
Well, the last time DARPA innovated something we got ICANN in bed with corporate America as the result.
Can't wait for 2010's Senate to explain to the rest of the planet that the Monroe Doctrine applies to our control of solar energy and the mysterious Burns Shield over the rest of the planet.
"Made up/misattributed quote that makes me look smart. I am on
...than looking for ways to bury waste products in the ocean.
Photocells are already fantastic technology. Not only do you save the energy you would otherwise be drawing from a power plant, you also save the energy needed to deliver the energy to the point where it is used.
A lot of public lighting near my home is now solar powered. The big advantage is that you don't have to dig trenches to the site. Trenching is very expensive because of the associated labour costs, and labour costs feed back directly into energy costs.
http://michaelsmith.id.au
Most of what Parent says is true- for the applications in question (home use, vehicle use, consumer use in general) the cost of solar cells is the limiting factor. However, this is DARPA we're talking about here- as well as a bunch of commercial clients. The applications mentioned in the article (primarily the military) rely heavily upon efficiency and not so heavily upon cost efficiency. Yes, it would be nice if GI Joe's GPS solar cell only cost fifty cents, but if it weighs a hundred pounds? I'd rather have a five-hundred dollar solar cell producing enough in half a pound. Efficiency is important in some areas, cost effectiveness in others. Research into efficiency isn't a total waste.
I used to carry a bottle of whiskey for snake bite. And two snakes. -Nefarious Wheel
But the article is almost talking as if the goal of doubling the now 25% efficency being doubled are being guaranteed to be met which is hardly the case - it's been over 30 years (where it was what 8% effieciency?) since solar cells were introduced and many other countrie/companies have been working on improving efficiency without that huge jump in performance - Germany/France in particular.
...the evil selfish "let's squeeze every drop from the Earth" oil industry doesn't buy up and discredit any commercial offshoots of this DARPA project and sweep it under the carpet. This kind of behavior is common, but the public rarely hear about it. The solution is for the world's populace to revolt by trying ever so hard not to purchase gasoline. Instead, whenever possible we should walk, bicycle or rollerblade to our place of work or relaxation until solar panels produce enough of our electricity to make a real practical difference. owonder.com/eco
O'WONDERWe're working on it.
compared to solar cells. Are you crazy or something? about the only place where land is more expensive is in or close to a city. Solar cells cost about $100 per sqft.. while land around here costs about $50k per acre, or about $1 per sqft. If you can get me some solar cells for less than $1 per square foot, I think we could have a good business.
-- these are only opinions and they might not be mine.
Be Afraid, Be Very Afraid I really encourage you to read the whole post.
~CK
Halliburton now owns the sun.
Never shake hands with a man you meet in a fertility clinic.
I agree with the poster that says cost efficency is the biggest problem. I'm not sure how much they cost, but my dream is to create skyscapers completely out of solar panel. I think the panels look sexy enough to be on a lot of things. They should experiment with different looks for solar panels and have entire cities dressed with solar panels. This would save a whole lot on enegry costs as would be the purpose for solar panels. They should also experiment with a impact resistant solar panel. That way we can dress our cars completely out of solar panel. Basically, I think they should focus their ideas on making solar panels dynamic so we may use them in lots of applications!
Why don't we switch to trying to develop optical rectennas. It seems to me that the only thing limiting there efficentcy is diode technology. We currently have diodes that can switch at 500 Thz. We only need to get into the 1000's of Thz to get into the optical realm.
This would allow for a much higher top theoretical efficentcy. Maybe around 90%+ and would be far cheaper to produce.
Urban legend.
Don't know if anyone remembers this, but in SimCity 2000, you could build a powerplant that consisted of a satellite which orbitted and collected solar energy, and them beamed it back down.
Perhaps a bit fantastical, however something that just popped in my head. Granted the efficiency of solar cells may leave a bit to be desired, but I'm sure that we've all heard the statistics of how many days the world could be powered from a day's worth of sunlight. More than likely a little embellished, but still. To me, it seems to me as though the main problems with using solar power as a viable alternate rests in efficiency and real estate. Obviously you need some area to place these things on. Sunlight loses a lot of energy through absorbtion and diffusion before it gets to the surface. Lots of unused space up in space as well. Why not build a huge array to float around in space? Might be an "easy" way to boost efficiency not just by simply improving materials, but also but capturing closer to the source... more signal-to-noise if you will.
and kenneth baker and the launch codes.
we want big boss's remains.
I'm also quite positive I remember stumbling across a webpage for a US Defense/space contractor, where they offered up solar panel "scraps" (stuff you could still assemble into working modules, with a fair bit of labor) for sale to the public. Efficiency was substantially higher than anything I've seen on the commercial market, though I don't recall figures off the top of my head. They probably cost a lot more to manufacture, but $50M amortized over -possible- solar panels sounds pretty expensive too.
Why couldn't we just give a $50M grant to homeowners to buy solar panels?
Please help metamoderate.
First I thought Highlander II, but a search for "burns shield" highlander turned up no results, Then I thought possibly The Simpsons and that was no dice, so what do you mean exactly?
The atmosphere lets through a very wide range of electromagnetic frequencies. Most solar panels use only a small part of this frequency range, and even in that range, its less efficient around the edges. If they make a cell that is 25% efficient, yet covers twice the bandwidth, they'd have the same energy output.
Now getting closer to 100% is harder. The amount of effort spent on making something efficient for a given frequency may be better spent trying to make it cover multiple frequencies (or layering cells that cover different frequencies). A solar cell that is 50% efficient sounds like it uses 50% of the suns energy output that that area, but might well be below 1% efficient.
"Give orange me give eat orange me eat orange give me eat orange give me you." -Nim Chimpsky
As a matter of interest, who do /you/ think owns BP Solar?
Replacing hydrocarbon energy with clean energy is not the only way to reduce hydrocarbon use. Making things more efficient will also reduce power use. This can mean better insulation in buildings and homes; more efficient means of travel; more efficient lighting (LED?); more efficient heaters and air conditioners; etc.
It might even mean smarter stoplights.
Think Deeply.
...is that so many of us even paused to consider the possibility.
If we are talking about traditional p-n type solarcells, they physically can't do better than ~37% IIRC. There is just no way to avoid some (alot!) charge recombination. In addition there is a lot of solar energy that is not within the absorption curve. I really hate it when people throw numbers around without a reference. All photovoltaics should be referenced to AM 1.5 (the typical energy that reaches the earth). The solar people all talk about photosynthesis as 'near 50%' but that is only over the narrow absorption range of the special pair and does not include any further electron transfer steps. I have to concur that it is all about making them cheaper. That said, while you can trade effiency for cost, the who 'nanocrystal photovoltaics' died a quite death cause the charge transfer was just SO piss poor due to it being an amorphous device. Now if someone can figure out how to add some structure (chemical self assembly) then you might have something. As with most other hyped science I would not hold your breath. Engineers are damn cleaver people and my bet is on the thin film amorphous silicon and cadmium telleuride ribbons being developed. solarcell
This was not their original plan at the outset. --Basically, they bought a property, and cleared a lot far back from the road. Then they learned that to have AC lines brought to their house from the mains, the local power company would charge them over $10,000 for the job of sinking four poles and running cable.
They thought, "Wow. Ten grand? Sheesh. What other options are there?"
The result was some research and a re-jigged construction plan using alternative energy. They spent about the same amount of money installing Geo-thermal and solar panel solutions.
10 big cells cost them about $8000 CAD. The rest of the money was spent digging trenches and laying thermal transfer pipes, air ducts and house wiring. Now they have all the power they need.
Strategic spot lighting using 12 volt halogen bulbs rather than bathing entire rooms in light minimizes the impact on energy reserves. Laptops are used instead of desktop computers, and various other appliances, like radios and televisions are run with DC to AC converters. Water is pumped from a well to a reservoir at the top of the house which provides pressure. Even while feeding the needs of an active family of four, the array of 5 big chemical batteries which stores electricity from sunlight never dipped below a 95% full charge on any of the days I visited. (The power readings were set on a cool display for all to look at.) --And the house is also absolutely enormous; 5 bedrooms, plus various huge family rooms the size of small churches, etc. A total mansion, and after the initial investment, it costs exactly zero to light and power.
Cooking is done on a big gas range fed from a pair of large propane tanks which contain enough propane to last more than a year. Water is drawn from a well. Refrigeration was the only puzzle still to be worked out, and while pondering it, the family had spent two years eating fresh foods while keeping milk and other such items in a basic camping cooler in the kitchen. Half the things people normally keep in their fridges don't really need to be there; milk and beef doesn't go bad all that quickly, eggs don't need to be refrigerated at all, and chicken and fish are simply bought fresh the day they are intended for consumption. --After realizing that this worked without any problems, the family basically concluded that they didn't really need a fridge in the first place. --Though, they told me that they had found a super-efficient 12 volt DC fridge on the market for homes exactly like theirs, but that they didn't think they really needed it.
Half the problem is not the power source, but the notion that we need so much electricity in the first place. --If we change the parameters of the problem, we can start using different solutions which have already been accepted by industry. Simple.
Despite the opposition, alternative energy is here for anybody who wants it.
-FL
It seems to have been forgotten in the last 2 or 3 decades that the most eficient use of solar energy for consumers involves not solars cells but just a bit of black paint, glass or plexiglass, and some pipes.
That is a solution that shifts the business towards plumbers and classical construction work, and would cut tremendously on fossil fuel use for heating. But that is not in sync with interests of any large industry (electronics) or the DARPA. No research involved, just plain urban planning and policy.
...is catching it.
It turns out you need a total surface area the size of a medium sized US state in about six places around the world (say one on each continent) to do the job.
Does anybody else see a problem covering Wyoming with solar arrays?
you can have my violent video games when you pry them from my cold, dead hands.
Prime UID Club
The article discusses that the goal is to improve the efficiency of solar cells to 50%. As I mention earlier in this thread, silicon-based semiconductor photovoltaics top out at a theoretical efficiency of about 25-26%. Other semiconductor technologies top out somewhere around 35%. These are the two technologies people think about when they imagine solar cells. I think the outlook for discovering and commercializing a semiconductor-based solar cell that's 50% efficient in the next 50 months to be very poor. I won't get into the physics, but the theoretical limitations have to do with the fact that semiconductor photovoltaics make inefficient use of the solar spectrum: a red photon will produce as much electrical energy as a blue photon, even though the blue photon is more energetic.
/. lately). Instead of trying to burn a ship, the focused sunlight heated sodium to about 1200 Celcius, which liquified it. That sodium was passed through a heat exchanger to boil water, which made steam, which turned a turbine, in a similar closed-cycle technology to a nuclear plant.
But solar power is not limited merely to what one can do with photovoltaics. When people talk about the many terawatts of solar power that falls on the surface of the earth, most of that solar goes into two things: photochemistry (like in plants) or to heating the earth's surface. Plants make very efficient use of the solar power that falls on them, and a black, nonreflective object will convert the incident solar power to heat (or reradiated infrared light) with extremely high efficiency. If we could focus efforts to developing technologies that capture sunlight first into chemistry or raw heat and converting that to electricity, rather than the direct conversion to electricity that photovoltaics do, we may have a better chance of reaching the 50% goal.
For instance, there was (is?) a solar power project that in the California desert that was a solar-thermal generator. Hundreds of mirrors focused sunlight onto a tower, much like the Archimedes death ray (which has received some press in
I'll admit this isn't much use in the battlefield, which is what DARPA is aiming for, but it is not out of the question to consider a smaller solar thermal unit for an encampment, which used a different medium than sodium.
Over two third of solar panels *on the earth* are produced in Japan and used there.
Maximum efficiency I've heard is 34%. Give them some incentive, they could improve little more.
If this administration is spending money on solar, it can only mean one thing...
Halliburton now owns the sun.
Not necessarily. All Halliburton really needs is the power to *destroy* the sun -- thus rendering the Earth uninhabitable. Top that, General Electric!
Now shut up, pay your bills, and enjoy your democracy.
-kgj
-kgj
As wondeful as it makes me feel that someone is sponsoring a warm fuzzy feeling technology like solar energy, the importance of these particulars are dwarfed by the greater issue at hand-- that the responsibility of government is to do what markets cannot. I dont know the numbers, but it certainly feels like government research spending has dwindled. $53mil may be spit in the bucket, but its at least something; it's certainly more than any corporation would invest in a 4 year, two month project.
Government needs to get back in the game of building a future actually worth living in.
Myren
Solar cells are not now, and will not in any near term (5-10 years) be a method for general electrical energy generation.
Generating electric energy with solar cells is a great idea, but they are still a speciality, because the price of the cells are so high. Prices are falling, and have been doing so for many years, but they still have a long way to go to be competitive to other large scale energy sources.
Solar cells needs more researching and funding for R&D. It will be great once it becomes affordable. Until then it is only a niche energy source for use in special locations and applcations.
For the time being the are luckily other sources for large scale non-polluting energy production, namely electrical energy from wind power. Wind power is a proven technology that is readily available and can be installed for large scale usage. It also has the benefit of being a decentralised, scaleable technology (start small then scale up).
The installed capacity for wind energy is like 20 times larger than solar power. In 2002 the world wide capacity for wind power was 32.0 GW, for solar cells it was 1.3GW. Numbers are from report by BP (the oil/energy company).
In many countries wind power is the fastest growing energy source. In Denmark 19% of electric energy is made by windmills. In Spain it is 6%, in Germany 5%. In actual numbers for installed capacity Germany is by far the leader in the field, then followed by Spain and USA. See ewea.org and gwec.net site for further numbers.
While most European countries are racing ahead and installing windmills on land and in the sea, not much progress has been done in USA in recent years. This is especially sad due to the population size of USA and the high energy usage per person.
Solar powered lighting is about the dumbest idea possible. Most lights are on utility poles, or near right-of-ways, with power lines at hand. And the electricity used at night costs pretty close to nothing because it's part of the utilities' base load anyways. Not to mention, you need batteries, which are still somewhat expensive, to run nighttime loads as opposed to just connecting to the grid to run loads like, say, peak air conditioning that return a greater benefit.
"I assumed blithely that there were no elves out there in the darkness"
Why couldn't we just give a $50M grant to homeowners to buy solar panels?
Welcome to the real world. First of all, there's no "we" involved. There's "the pentagon".
Since you're just joining us here on planet Earth, "the pentagon" is not interested in Americans being energy-independent. They are interested in waging war every few years. That's their job. They do a fine job of it. And in order to keep doing their jobs, it's in their interests to ensure that Americans are insecure and frightened enough to keep paying them to do their jobs.
Now, a seemingly miraculous opportunity for continued warfare (and funding) has arisen for the pentagon, in the Middle East. It just so happens that a large portion of our energy comes from the Middle East. And it just so happens that the pentagon does a great job waging war in the Middle East to secure that energy that we desperately need (or, at least, they did until recently).
So, I hope you can see that Americans being independent of energy from the Middle East is not in the pentagon's interests. In the future, when you see that the pentagon has funded something, instead of thinking "why didn't they fund something useful?" you can think "those brass sure are doing a heckuva job!"
"I assumed blithely that there were no elves out there in the darkness"
Look at the wonderful things the federal govt. can do when Bush is distracted!
Maybe if he gets even MORE distracted, our budget will balance and drug use will go down! Quick, someone get a small, sparkly object to show him!
(If I as a conservative feel this way one year into his term, I can't imagine how you pinko liberals feel.)
I have two solar powered businesses here (a computer consultancy, and a machine/plating shop), and two homes which run off the same systems. Square feet definitely matter, as I am nearly out of useful roof space now. The 1000 sq foot building that has the machine tools is covered, and could use twice what I have now (although with a 2kw array, it could also be worse - 8-10 kWh a day ain't bad). I've got room for one more rack of 4 panels (about 500w more in full sun). A 500 sq foot building has its roof completely covered as well, and usually I have to pump power from the larger system over there to back it up when things aren't ideal. Any well designed solar system has the problem of, well, February...The Solarex polycrystalline panels I have on both places (2 of the four buildings that aren't always in shade) do the best in "non full sun" or gray days of all the types and brands I've tried, and this MATTERS in real life, bigtime. Getting half or even a quarter of the full sun output is far better than nothing, for example, and there are times when one either lives on this or burns petroleum in a generator, which is very expensive. But employees expect to work and get paid no matter the weather, so one copes. Remember that lead acid batteries have lousy efficiency, down to 40%, so the generator or panels lose a lot there if you're not using the energy as it comes in. There is simply not enough room on the average building around here (SW VA) to handle the bad weather months. This is a system that can run air conditioning and BIG multi HP power tools on good days...and barely limps by on nightlights if we have a week of near darkness, which happens often enough.
Not just for solar, but for alternative energy in general. With our oil supply set to become uneconomical within forty years, we are literally in a sprint to find a replacement for fossil fuels wherever we use them today, and if we don't our society is going to hit the reset button for about a century or longer. Our entire economy is based on cheap and plentiful fossil fuels, ALL OF IT. Our commitment to alternatives so far is a joke in the US. $53 million isn't even a rounding error on what we need to be dedicating to this effort, which is likely already ten years late.
I'd read that spray-on plastic solar cells will bring down costs despite their lower efficiency, but how do you wire them up?
Michael Moore owns stock in Halliburton
Life is not for the lazy.
"Strategic spot lighting using 12 volt halogen bulbs rather than bathing entire rooms in light minimizes the impact on energy reserves."
Halogen lighting is absurdly inefficient. Incandescent lighting in general is. Imagine if they used fluorescent lighting in their house? Heck, even LED or HID would be much more efficient.
I've never heard of a super-efficent 12V fridge either. Many 12V "fridges" (more like coolers) are god-awful Peltier devices which are about 10% as efficient as a compressor-based system. Even of the compressor-based systems, I'd imagine a 120V one would be more efficient anyway due to fact that high voltages work better for high-load uses.
I don't get why 12V is considered a good thing here. Power loss in a line is proportional to the current through the line. To deliver the same power at 12V as at 120V, you have to run 10X as many amps and thus lose 10X as much power in line losses.
I do agree people could use a lot less power (I am very power usage conscious) and I know conservation is the biggest part of solving our problems with providing energy for the future.
But I also know that not every house is willing to go without refrigeration and ice. What if you have medicines you need to keep?
Finally, having looked lately, it is amazing how much the power coming from the sun varies. Did you know that if the sun is blocked by a cloud the power falling on a panel (and thus the power generated) falles to 10% of full sunlight numbers? And if it's a heavy overcast, it's even worse. This combines to mean that just in much of the country (I think of Michigan, where I grew up), solar power is not viable at this time. We'll know solar power is viable in those parts of the country when people in areas like California and Arizona can't afford not to install cells.
I mean, think of it like this. My monthly electric bill is about $40. If I had sells capable of covering my electric bill in Michigan, I could take the same cells to California where they generate $400 of power per month and sell back $360 worth of power per month! They'd pay themselves back in 18 months.
Well, I don't see every house sprouting solar cells in California yet (although I saw a new PV setup appear on my commute in the last month, I'm jealous), so I know solar power isn't ready for prime time.
And then of course, all this idea of solar houses is predicated on the idea that everyone owns a single-family home. So in order to save power, you have to move to the suburbs and thus drive 14,000 miles a year (at least) in commute plus puttering to the supermarket to get groceries, when in a more efficient city environment you'd use less energy overall.
I have a friend who owns an entire mountain nearby (small one), with a house, entirely off the grid, much as for your friends, running electricity from the grid wasn't very cost-effective. Alternative energy is a reality for him for sure. Of course, just the PV array cost him $30K. I don't know how much cheaper it would be now, I'd hope it would be significantly cheaper.
http://lkml.org/lkml/2005/8/20/95
I used the numbers from solarbuzz.com. http://solarbuzz.com/ Cost of a panel right now is $5.20 per peak Watt. For more facts, also see http://www.solarbuzz.com/Consumer/FastFacts.htm.
So I did some numbers. My electric bill is about $40/mo from PG&E. I use about 353KWh/month.
I figured that there are about 6 effective peak hours of generation per day. That is, I get about 12 hours, but if you average it all hour, it's like I get peak sun for 6 hours (Solarbuzz says 5.5) in my area.
Okay, so that means for each $5.20 I spend, I get 6 WH per day. Since I use 11.8KWH/day, that means I need about 2000 peak watts of generation. That means I'd have to spend about $10K on cells (not including tax, and solarbuzz says the PV array is only half the cost of the system). At $40/month, that means it will take me 20 years to get my money back (really, double this), hopefully my cost of new lead-acid batteries every 4 years or so won't turn that 20 years into never.
And that's in sunny California, if I chop down the trees that shade my house and keep it cool. Oh, and I don't even have A/C!
So, what did I do wrong? Where's the magic of solar power here? Sounds like I'd have to take a huge bath to go solar.
Were just referring to ROI on energy put in?
http://lkml.org/lkml/2005/8/20/95
Check out this solar tower project. It uses the sun to heat up air which is under an enclosed canopy. The heated air then rushes up through a gigantic tower, powering generating turbines along the way.
http://www.rootstrikers.org/
of estimates are made up on the spot.
This is dwarfed by the subsidies that govts give to the world's richest industry, Oil.
If i had some mod points left thats what i'd have done .
,find another
Seriously , Wonderkid has a point . With so much money and technology under the control of
an industry that is diametricly opposed to sustainable fuels its no wonder they seem basic
at the moment .
Most solar panels at present don't genereate as much energy as it takes to make them , that
doesn't mean they are useless , just that they aren't ready yet . Every technology goes through this phase at some point , it usually takes a bit of a risk to get it to the mainstream. Once its there it benefits from the massive exposure and improves dramatically.
Wake up people we can't carry on using Petrol , wonderkid has the right idea
way to do things. Don't wait for the government to say 'right everyone , stop using petrol now' , they won't thats where they get their money from so they aren't going to cut their
revenue.
You can take control of your life , your planet , your destiny or just throw it all way with lazyness and fear. The choice is yours but the effects are all of ours. choose carefully.
[site]
I'm sure I heard this somewhere, that if we took 1% of the Sahara desert and turned it into a
solar array for producing electricity we could feed the world with it! even if this not true I'm sure
it could produce electric for at least Africa, surely.
But anyway, instead of making new advanced solar cells why not use the ones we have their
very good! I'm not a complete know it all, but I know that the money could be better spend
many other ways.
It's not really the price of solar panels but the return on investment. How much do you pay and how much do you save and over how many years do you amortize the cost of the panels. If you pay lets say 200% for more efficient panels ($5/watt goes up to $10/watt), but the efficiency goes up by 400% (12% to 50%), the return on investment has just doubled even though you might have to pay more for the original.
Even still, it took a lot of work to get the bank to allow a building loan for the house; the bank's concern was that an eco-friendly house would be difficult for the bank to re-sell if the original owner failed to pay back the loan. It took a fair bit of fighting and many phone calls up the chain to bosses of bosses and a bit of threatened media attention. ("What? Your bank doesn't support environmentally friendly housing? What will the public think?") to convince the bank CEO to approve the mortgage.
-FL
-FL
I'm not an electricity guru, but I'll try to answer as best I can. . .
Halogen lighting is absurdly inefficient. Incandescent lighting in general is. Imagine if they used fluorescent lighting in their house? Heck, even LED or HID would be much more efficient.
I agree that I do find LED lighting an exciting technology, but I'd be hard pressed to go with it in a house; it's a very blue and cold light. I dislike fluorescent for those same reasons and because even the special units designed to replace incandescent bulbs where special effort has been spent to make them seem more natural, I still find buzz and make me feel weird.
In the house I'm talking about, in the washroom for example, the toilet and sink would get their own lights pointed at them, and that's it. At first, I found this a bit strange when compared to the whole-lighting experience of a regular house, but it was easy enough to adapt. You can still read on the john and get your business done. The rest of the house took a similar approach.
I can't say if this really did use less energy than a house filled with 100 watt bulbs, but it didn't seem to make much of a dent on the house batteries. Perhaps if the family converted their lighting to AC from the batteries and used regular bulbs it would have been a better solution. I'd like to really study this stuff before I get around to building my own house, which I plan to someday.
I don't get why 12V is considered a good thing here. Power loss in a line is proportional to the current through the line. To deliver the same power at 12V as at 120V, you have to run 10X as many amps and thus lose 10X as much power in line losses.
Again, I don't know. --But I should think the distance being traversed would factor into that. They weren't moving electricity over kilometers. Just meters.
But I also know that not every house is willing to go without refrigeration and ice. What if you have medicines you need to keep?
Medicines were also the only big thing I could think of when pondering the necessities of keeping a fridge. Other than that, it seems more like a device of convenience. And these days, I find myself keeping water out on the counter because I like drinking it at room temp. I keep things like left-overs in the fridge (until they go moldy and get thrown out), and frozen berries and instant pizzas and that sort of thing. Nothing a little less laziness wouldn't do away with. There are other ways of preserving fruits and meats. And in any case, I've never had to keep any medicine in the fridge, nor have I had to keep any real medicine in my home aside from asprine. This was also the case when I was growing up, and with virtually everybody I know. --I realize that it may seem like a broad statement, but it appears to me that many medicines on the market are a product of poor thinking; eating habits and lifestyles and living/working environments which do not encourage good health. A more harmonious approach to living of which eco-friendly housing is a part, probably does away with the need for any number of chilled pharmaceutical solutions.
Finally, having looked lately, it is amazing how much the power coming from the sun varies. Did you know that if the sun is blocked by a cloud the power falling on a panel (and thus the power generated) falles to 10% of full sunlight numbers? And if it's a heavy overcast, it's even worse. This combines to mean that just in much of the country (I think of Michigan, where I grew up), solar power is not viable at this time. We'll know solar power is viable in those parts of the country when people in areas like California and Arizona can't afford not to install cells.
Again, I don't know the technical details about the panels the family in question installed, but I do know that it gets pretty cloudy up here in Nova Scotia. The owner of the house did explain that there are different types of solar cell, and the reason the ones he installed were so expensive was that they w
Windmills are not really "Man's best hope for energy". When is there the most wind? Spring and fall. When are energy needs the highest? Summer and winter. Besides this they are not very powerfull (large number needed to power a city), kill loads of migrating birds (strange/macabre but true), and the weather is not exactly something stable enough to build your energy grid on. Oh yeah: it can be cloudy and windless.
I see much more potential in wave-energy; which probably hasn't taken off yet because one practice experiment in Norway got 'blown off' after a violent storm wrecked it, and because it isn't in the public eye much.
Additionally, paying up front raises your costs. I mean, a dollar 20 years from now is a lot less than a dollar today.
I don't agree with your contract thing. I am comparing cost of PV power versus regular power, to get an idea of whether it makes sense for the person who is already accustomed to regular electric rates. Additionally, California is considering limiting the ability of anyone (even companies) to sign power contracts outside the regular system, so that might not even be an option for me soon.
I redid the numbers a bit, after reading more info on solarbuzz.com. It says that in large installation (meaning like a house setup, not a couple watt setup), the cells are more like $3.80 per peak Watt, not $5.20. The bad news is that it also says the cells are only half the cost of the system. So I redid the numbers, and they break even after 30 years, not 20.
This is disturbingly outside the expected lifetime of the systems of approximately 25 years. And that's before replacing batteries every 4-5 years. And omitting the mention that the output of the cells will drop 0-20% over their 25 year lifetime.
Still, all is not lost, PV solar has advanced so much in the last 5 years, things will likely look different in another 5. So I guess I'll keep waiting.
Additional notes:
Solarbuzz says that a cloudy location generates almost half as much in a year as a sunny location. All I can say about that is that I must have grown up in a very cloudy location. Because I'd say about half the days are overcast in Michigan in the summer, and very few days aren't significantly cloudy. Knowing that this will reduce power output at least 80% on those cloudy and overcast days, I can't see how it makes half as much power as here in California, where we have clear skies 90% of the time and the sunlight is just plain stronger anyway (closer to the equator).
Finally, the post I had responded to talked about total energy output of a panel versus energy put in. Solarbuzz says that the cells will output as much energy in 2-4 years (depending) as was created to make them.
http://lkml.org/lkml/2005/8/20/95
I looked at that web page. They don't give their capacity units, but I'm gonna have to assume it is in liters.
f rig.display_products_html, the freezer at the top of the list uses 45.46666667 KWH/cu ft/year, which is 10% less.
That means the freezer on that vestfrost site uses 51.13904511 KWH/cu ft/year.
Now, at the energy star site http://www.energystar.gov/index.cfm?fuseaction=re
I'm sure there's some fudging I'm missing in these numbers, but I don't see how those devices you list are super-efficient. Efficient, yes. Super-efficient, I just don't see it.
Luxeon LED lighting is fine, but white LEDs (these included) aren't as efficient as fluorescent lighting.
http://lkml.org/lkml/2005/8/20/95
Basically, you have a heavily insulated storage "unit" - an old, large chest freezer will work fine. Get rid of the compressor, coils, etc, then seal any holes or cracks. Dig a really large hole, deep enough to hold the chest, leaving a couple of feet completely around the box. Fill the bottom up with a foot or two of straw, old fiberglass insulation, sawdust, etc - basically some insulation material. Center the chest in the hole on top of this layer, then backfill more insulation completely around the unit on all sides. Take the lid and build a new cover for the top around the lid, adding 6 inches to a foot of insulation. Basically, you want to beef up the insulation something severe. If you want, you can also build this whole thing aboveground as well (for Nova Scotia, you might want to do this) - but it is more difficult. I imagine, though, a bunch of two-by-fours and some effort will see you through.
Once you have the unit built, operation is "simple" (though time consuming at inconvenient times for humans): In the daytime, leave the unit closed as much as possible to keep the cold inside the unit. When the sun sets completely (when it gets nearly completely dark and it cools down), open the unit up entirely. Any heat inside will radiate out toward the night sky. Before the sun rises the next morning, close the unit up. Repeat this cycle forever.
If you put a cookie sheet with a half-inch of water in the bottom of the unit, you can even make ice (though it will take a few cycles)! So - items that need to be kept the coldest stay at the bottom. I would imagine that a very enterprising person could build such a unit as a room, with the walls heavily insulated (maybe straw-bale construction, or something similar), with a retractable heavily-insulated roof section controlled by a computer or a simple solar cell tracker system. A door on the side would allow entry into the unit (maybe want to make it an "airlock" type system to keep the cold from exiting), and steel shelves inside would allow easy storage and retrieval of food items.
If you want to try the idea out, make a small version with a cheap camping cooler and a thermometer over a few night/day cycles, to see how far you can drop the temperature (I am not sure such small system would work well, though - it is one of those things where area of exposure might make all the difference). There is information on the internet about this kind of system - I am certain the Mother Earth News has also covered it in the past as well.
Finally - for you nitpickers out there concerned about my use of the word "cold" and "letting it out" - please be aware that I am aware of how heat moves, and that you aren't moving cold anywhere. I am just speaking in layman's terms here because it is easier for others to visualize...
Reason is the Path to God - Anon