New Solar Cell Sets Record For Energy Efficiency 165
Lucas123 writes "After three years of work, German and French researchers have achieved a new world record on converting sunlight to energy through a photovoltaic cell, achieving a 44.7% rate of efficiency, which was measured at a concentration of 297 suns. The efficiency rating means the solar cell collects 44.7% of the sun's spectrum's energy, from ultraviolet to the infrared spectrum, which is converted into electrical energy. The team of researchers said the technology places them on the path to achieving their roadmap of 50% efficiency in solar energy conversion."
Better than gasoline energy efficiency (Score:2, Informative)
Re:Better than gasoline energy efficiency (Score:4, Interesting)
Not much point in comparing the efficiency of an energy source with the efficiency of an energy sink; they're at the opposite ends of the energy cycle.
Unless you can use your solar-electric power immediately, you also need to add a whole conversion system for storage and discharge which can be quite lossy if you choose electrolysis for energy storage due to much higher energy density than batteries.
To make a fair comparison, you would need to pit two options with similar energy cycle against each other. Something like solar-hydrogen vs solar-biodiesel or solar-ethanol. Growing algae and converting it to biodiesel or ethanol to keep internal combustion engines running might be more efficient overall than electrolysis to produce hydrogen before converting that back to electricity to drive electric motors. Ethanol and biodiesel also have the benefits of well-established distribution channels while high-pressure hydrogen is still scary for many people.
I'm not including plug-in electric since everyone I know seem to be highly skeptical of their operating range and seriously worried about battery replacement costs that can quickly wipe out any fuel savings.
Re: (Score:2)
Unless you can use your solar-electric power immediately, you also need to add a whole conversion system for storage and discharge
Or, sell it for a tidy profit. If needs be you can buy it back later at night when electricity is cheaper due to less demand.
Re: (Score:2)
Price dropping, usage growing, rage increasing (Score:5, Interesting)
At cleantechnica site you can see a priced drop of $76/w to under $.74 a watt in only (sorta wish it was .76 a watt for neatness sake, dontcha?)
http://cleantechnica.com/2013/05/24/solar-powers-massive-price-drop-graph/ [cleantechnica.com]
You can also see a similar exponential but reverse growth curve off a link from that page.
Elsewhere, I saw solar was projected to generate more energy than the U.S. currently generates by 2050-- and to quintuple from there by 2100.
---
Loved "Mystery Men". On my top 100 list.
Re: (Score:2)
I'm still waiting for a Solar powered Fraculator.
Re:Price dropping, usage growing, rage increasing (Score:5, Insightful)
As usual, an XKCD [xkcd.com] comic applies...
You always have to be careful about extrapolation. What looks like exponential growth is unlikely to stay that way as further order effects come into play.
Re: (Score:2)
Re: (Score:2)
I'm not saying it's going to break now. I think it'd break(IE level off) before solar alone outstrips all current power generation in the USA.
Also, it takes more than 2 data points to even extrapolate for exponential growth.
Re: (Score:2)
Also, it takes more than 2 data points to even extrapolate for exponential growth.
Then it's a good thing there's more than two data points there. But let's consider your assertion. One can take the log of the value part of the two data points (which are value-time pairs). Your XKCD link already showed the scientifically dubious but very feasible approach of extrapolating a line from two data points. Exponentiating back to the original values yields an exponential curve.
Hence, you just extrapolated an exponential curve from two points.
Re: (Score:2)
If the underlying equation is exp(ct), c=arbitrary, t=time, 2 points suffice to determine a (real-valued, unique) c.
If the underlying equation is b+exp(ct), 3 points are needed to determine b and c.
Re: (Score:2)
Not if the equation is degenerate and b=c.
Re: (Score:2)
If the underlying equation is exp(ct), c=arbitrary, t=time, 2 points suffice to determine a (real-valued, unique) c.
There we go.
Re: (Score:2)
Then it's a good thing there's more than two data points there.
Yeah, misread your original post; rereading later I saw the deal. My original point was more along the lines that if you look from the initial cell culture bacterial growth in a petri dish will be a very clear exponential curve - right up to the limits of the dish. I don't think that solar adoption is going to slow anytime soon(other than regular already known swings), it's just that taking it to 2050 and 'more power than the USA currently uses' is a bit far to be extrapolating.
Solar power is not suited f
Re: (Score:2)
Here...
Give it a look and let us know what you think...
http://solarfocus.blogspot.com/2009/02/solar-goes-supernova.html [blogspot.com]
Re: (Score:2)
What happened in the early 90's that made the price go back up? Is that just noise in the graph? Subsidies dropped?
Well of course (Score:5, Funny)
Comment removed (Score:5, Interesting)
Re:Well of course (Score:4, Funny)
Re: (Score:2)
Re: (Score:2)
That solar data just goes to further illustrate that if the Gulf Stream were to ever shift or cease, Europe would be utterly screwed.
Re: (Score:3)
Re: (Score:2)
That solar data just goes to further illustrate that if the Gulf Stream were to ever shift or cease, Europe would be utterly screwed.
In what respect?
If the gulf stream changes we likely get more sun ...
The gulf stream mainly only influences temperatures in winter, I would say in summer its effect is rather low (regarding warmth) and causing more clouds.
Re:Well of course (Score:5, Informative)
From the Wikipedia article [wikipedia.org], in 2012 Germany had 32.6 GW of installed PV solar capacity, and it generated 28 GWh of electricity. A year is 8766 hours, so that's an average generation rate of 28000 GWh / 8766 h = 3.19 GW. So their PV solar capacity factor is 0.098 (Numerous hits on Google reporting instantaneous generation and generation over 24 hours notwithstanding - those don't matter, only the long-term cyclical average does, a natural cycle of seasons being one year.)
Basically, Germany is a terrible place to install PV solar [wikimedia.org]. The only reason it's viable there is because their green energy initiatives have driven up the cost of their electricity [wikipedia.org] to about $0.34/kWh (vs about $0.20/kWh for France and the UK). Numerous studies put the cost of electricity from PV solar [wikipedia.org] at about 2x-5x the cost from other sources. So normally it wouldn't be cost-effective. But if you raise electricity prices to 3x what it is in the U.S., suddenly PV solar becomes financially viable.
Re: (Score:3)
You simplify to much.
Meanwhile a nice placed solar plant would be cost effective even without the granted feed in tariffs.
This is due to the fact that you can sell your energy at the spot market and the price for energy peaks there regularly far above the feed in tariffs.
Capacity factors ... an invention by wikipedia ... and some guys who gives talks in TV shows ;D
No one in the energy business uses that term, it is completely useless.
Re: (Score:2)
You simplify to much.
Meanwhile a nice placed solar plant would be cost effective even without the granted feed in tariffs.
This is due to the fact that you can sell your energy at the spot market and the price for energy peaks there regularly far above the feed in tariffs.
Only because government regulations mandate renewable power always be purchased, often times leading to negative electricity prices (i.e. power company pays you to waste electricity - nice perverse incentive!). This is basically the same as a tariff - a law meant to protect a particular industry even though its consequences on the whole are a net loss.
Capacity factors ... an invention by wikipedia ... and some guys who gives talks in TV shows ;D
No one in the energy business uses that term, it is completely useless.
I hope that was sarcasm, otherwise you're an idiot.
Re: (Score:2)
> No one in the energy business uses that term, it is completely useless.
I'm in the energy business, and we use it all the time. So does everyone else, like
The EIA: http://www.eia.gov/tools/faqs/what-capacity-factor
The NRC: http://www.nrc.gov/reading-rm/basic-ref/glossary/capacity-factor-net.html
NREL: http://www.nrel.gov/analysis/tech_cap_factor.html
The RMI: http://www.rmi.org/rmi/Capacity%20Factor
The EPA: http://www.epa.gov/airtransport/pdfs/TSD_capacity_factors_analysis_for_new_units_7-6-10.pdf
along wi
Re: (Score:2)
It's only terrible if you ignore the external costs of other production methods. Once you factor those in German solar PV looks pretty good against nuclear and coal, although not nearly as good as wind.
Break-even in New York (Score:2)
$0.34/kwh is already what we pay ConEdison in NYC. So we're already at break-even here. ConEdison has raised rates double-digit percentages every year for the past 10 years. The price per watt solar panel installation has fallen to $2, and that's dropping quickly. With those two trends we don't need any government intervention to produce a sea-change from centralized- to distributed power generation in this country in the next decade.
There is also the not inconsiderable effect Hurricane Sandy had on hea
Re: (Score:2)
> Numerous studies put the cost of electricity from PV solar [wikipedia.org
As one of the people that wrote the article you're quoting, perhaps I'll jump in here
> at about 2x-5x the cost from other sources
The price of power from any source is dominated by three things, the CAPEX or how much you payed to build it, the OPEX (or O&M) which includes fuel costs and maintenance, and the duty cycle, what percentage of the time it runs at its full rated power. So, for instance, if you run the calculation f
Free to play - pay to win. (Score:3)
In short, their 'leadership' is artificial and shallow - bought and paid for, and likely only persisting so long as their market remains distorted by law. And your research missed a further distortion - a tariff on non-renewable energy that's used to subsidize renewable energy installations. (Which can then sell their power at the legally mandated above market rates.)
Re: (Score:3)
For a bit of perspective, the only condition where there can be a free market is anarchy. Once there is any rule of law in any political system (difficult to have one without the other, I think; in fact, to define one rather requires the other) there is skewed market because most law is economic law. Even in criminal law the bulk of it involves property in some form. (There is no way to use law to establish a level playing field; the very act of trying prohibits such - someone is always at a disadvantage
Re: (Score:2)
*Yawn* Sophomoric semantic games.... You, and every reader with even a smattering of education, know damn well what I meant.
Re: (Score:2)
297 Suns? (Score:2)
Re: (Score:3, Informative)
Re:297 Suns? (Score:4, Insightful)
I do not think pholtovoltaics are limited by the Carnot efficiency, which applies to the conversion of heat to mechanical work in heat engines. The energy stored electrochemically in batteries can exceed the Carnot efficiency, as can fuel cells.
Re: (Score:2)
Carnot efficiency does apply, because it black-body radiates away energy as part of the process, and therefore is a simple heat engine to some degree. In fact, everything above absolute zero is, including fuel cells. They operate at lower temperature differences and therefore the effect is smaller, but it's there nonetheless.
Further reading:
https://en.wikipedia.org/wiki/Shockley-Queisser_limit
Re: (Score:2)
Solar panels do not exclusively operate in the infrared spectrum, so i'd be willing to venture a guess that carnot's law doesn't' apply to photovoltaics, but would apply to solar thermal.
Re: (Score:2)
There specialized cell for solar farms. They will be under a lens.
Re: (Score:2)
Re: (Score:2)
Re: (Score:2)
Re: (Score:3)
If that was too confusing, consider that mirrors are a lot cheaper than these solar cells so an array becomes a collection of dishes instead of flat panels.
297 Suns? (Score:2)
What's the actual efficiency when used at a single sun? Is this technique only useful with hundreds of mirrors?
No mention of economics.... (Score:2)
Re:No mention of economics.... (Score:5, Informative)
Multi-junction cells are expensive to produce, using techniques similar to semiconductor device fabrication, usually metalorganic vapour phase epitaxy but on "chip" sizes on the order of centimeters. In cases where outright performance is the only consideration, these cells have become common, they are widely used in satellite applications for instance, where the power-to-weight ratio overwhelms practically every other cost.
Re: (Score:2)
Yet it can still be "affordable" because these are designed to achieve this efficiency at 297 suns' worth of energy. Thus you have 297 cheap 1 m^2 mirrors reflecting sunlight at just a single 1 m^2 solar panel. So if the panel costs less than 297 times the cost of a normal solar panel designed to capture a single sun's worth of energy, it is actually cheaper (not counting cost of mirrors or active hardware to aim the mirrors as the sun moves across the sky, but you get the idea).
Re: (Score:2)
Actually it's a 4cm*4cm fresnel lens focusing on a 2mm diameter cell. http://www.soitec.com/en/technologies/concentrix/components/ [soitec.com]
Re: (Score:2)
Multi-junction cells are expensive to produce, using techniques similar to semiconductor device fabrication, usually metalorganic vapour phase epitaxy but on "chip" sizes on the order of centimeters. In cases where outright performance is the only consideration, these cells have become common, they are widely used in satellite applications for instance, where the power-to-weight ratio overwhelms practically every other cost.
MOVPE/MOCVD growth methods are not inherently limited to small chips that are centimeters in size. Researchers might be growing smaller samples during R&D because of limited reactor sizes, and the expense and difficulty of handling large wafers. Once the technology is demonstrated on small wafers the design can be scaled up for growth on larger wafers.
Commercial MOCVD reactors may grow on dozens of small wafers simultaneously in a single chamber, and the wafer sizes can also be increased. Commercial
Re: (Score:2)
I wrote the statement you quoted. Feeling proud now.
Solar cell efficiency graph (Score:5, Informative)
Here is a graph of solar cell efficiency [wikimedia.org] showing the different kinds of materials used to make them. The typical solar cell [wikipedia.org] is silicon (blue on the graph) and maxes out at 27.6% efficiency.
Rare elements? (Score:2)
Re: (Score:2)
Re: (Score:2)
Do they need rare elements? TFA does not say a word about it, and it is important: if the answer is yes, then it is not economically viable.
What a nonsense. Why don't you check prices for rare elements? Or get an idea how abundant they actually are?
Don't Envy Germany's Energy Policy (Score:4, Informative)
"Germany's Energy Poverty: How Electricity Became a Luxury Good" Spiegel 09/04/2013 [spiegel.de]
German consumers already pay the highest electricity prices in Europe. But because the government is failing to get the costs of its new energy policy under control, rising prices are already on the horizon. Electricity is becoming a luxury good in Germany, and one of the country's most important future-oriented projects is acutely at risk.
Re: (Score:2)
Another Tea Party dream and Fossil Fuel industry hope. The more solar technology advances and begins to encroach on fossil fuel profits, the more of these "no we can't" nay-sayers come popping out of the wordwork. If solar cells go the way of IC's, the industry will replace fossil fuels entirely in 50 years. The future will be owned by those who invest in solar now. Its inevitable.
Re: (Score:2)
I don't know about that -- this article which ran recently in the NY Times would seem to back the notion that Germany's energy policy is complicated and is making electricity expensive enough that it is beginning to have
unintended consequences.
http://www.nytimes.com/2013/09/19/world/europe/germanys-effort-at-clean-energy-proves-complex.html?pagewanted=all [nytimes.com]
I don't know if it's a "real" phrase, but you might call it energy poverty -- when electricity is so expensive it becomes a driver of poverty. The guy in
Re: (Score:2)
The Laser he used was Solar Powered not the Golden Gun. He was an assassin that used a Golden Gun that shot bullets made of gold. [wikipedia.org] Do you also have three nipples?
Re:Awesome. (Score:5, Funny)
No. But the Saudis are investing in cloud technology.
Re: (Score:2)
Its a good thing the Chinese have been practicing cloud killing technology [reference the Olympics]
Re: (Score:2)
Re: (Score:2)
Lens
Re:The 44.7% efficiency requires 297 suns (Score:5, Informative)
"...a photovoltaic cell, achieving a 44.7% rate of efficiency, which was measured at a concentration of 297 suns"
This means that they use mirrors to focus the light onto the panel. Since high-efficiency panels tend to be expensive, the more light you can concentrate on it, the better. The fact that it can handle a near 300 fold increase in throughput is a good thing. These are not going to be used on a residential roof flat panel anytime soon.
Re:The 44.7% efficiency requires 297 suns (Score:5, Insightful)
It will take a while for the technology to hit the manufacturers but it will hit panels for satellites first. When you are paying $20k per pound (0.5kg) to put something in space if you can get a higher efficiency with less weight you can pay a LOT more for the panels and still come out ahead.
Re: (Score:2)
Re: (Score:2)
Pssst - Although not guaranteed, if they get 44.7% efficiency at 300x normal sunlight... They probably do similarly under 1x sunlight. Claims like the one made don't describe a requirement for that efficiency, they describe an extreme under which the cells can still perform
Re: (Score:2)
Reflectors aren't weightless, and neither are the extensive heat removal systems that will be required to cool a concentrated solar cell in space. I've never seen a representation of a satellite with anything but unconcentrated cells. Pssst - Although not guaranteed, if they get 44.7% efficiency at 300x normal sunlight... They probably do similarly under 1x sunlight. Claims like the one made don't describe a requirement for that efficiency, they describe an extreme under which the cells can still perform. As in "oooh, we only need one $1000 panel and 297 $10 mirrors, rather than 297 $150 panels"
......And, 297 times the surface, plus the added wiring etc. Only way to measure in a meaningful way is fixed cell, no concentrators, 10+ days during the equinox. Ah, do not forget diesel generators or batteries to guarantee continuous output, will ya?
Re: (Score:2)
Ah, do not forget diesel generators or batteries to guarantee continuous output, will ya?
Isn't it better to stop looking for excuses why not to upgrade the energy (re)distribution infrastructure? Over a large area, there's sun or wind somewhere most of the time, definitely more often than over a small area. Perhaps it's time to stop thinking locally.
Re: (Score:2)
Isn't it better to stop looking for excuses why not to upgrade the energy (re)distribution infrastructure? Over a large area, there's sun or wind somewhere most of the time, definitely more often than over a small area. Perhaps it's time to stop thinking locally.
Even thinking locally, with an efficient enough panel you'll still get meaningful energy output during a rain storm. It's not total darkness during these conditions, and supplemented with battery backup to even out the load during lean times you should be fine.
That being said, I still prefer ideas like the liquid salt plant outside of Seville. Focus the sun's light with mirrors to a giant thermal battery and use that to power turbines.
Re: (Score:2)
Isn't it better to stop looking for excuses why not to upgrade the energy (re)distribution infrastructure? Over a large area, there's sun or wind somewhere most of the time, definitely more often than over a small area. Perhaps it's time to stop thinking locally.
Even thinking locally, with an efficient enough panel you'll still get meaningful energy output during a rain storm. It's not total darkness during these conditions, and supplemented with battery backup to even out the load during lean times you should be fine.
That being said, I still prefer ideas like the liquid salt plant outside of Seville. Focus the sun's light with mirrors to a giant thermal battery and use that to power turbines.
want an economic proof that the molten salt storage is a Rube Goldberg [wikipedia.org] ? there are lots of situation, predating the solar craze, where an economic way of storing and releasing energy in bulk would come in handy, and molten salt technologies date back to the late 1950ies. But no one used them, even when "Global warming" was not in the vocabulary and baseload generators were way more efficient at producing low cost energy than peak generators.
in most situation, it's better to use a generator at peak capa
Re: (Score:2)
Yep, during hurricane Sandy my 13W solar panel was still putting out enough power to keep my pair of 3W light a life [amazon.com] lamps going. They might "only" be equivalent to a 45W bulb but when the powers out and the house is mostly dark that's a lot.
Re: (Score:2)
"Even thinking locally, with an efficient enough panel you'll still get meaningful energy output during a rain storm. It's not total darkness during these conditions, and supplemented with battery backup to even out the load during lean times you should be fine."
In particular, multi-junction cells like these ones do better than conventional cells under these circumstances. A conventional single-junction cell loses about 1/2 the energy available in blue light, which is what the panel sees when the sun isn't
Re: (Score:2)
Ooh. I like that... I think I need to get some of those for my next camping trip. :)
Re: (Score:3)
I've never seen a representation of a satellite with anything but unconcentrated cells.
What about Deep Space 1 [nasa.gov]?
Re: (Score:2)
Why bother putting them in space? Even if you could beam the power to earth at 90% efficiency, you'd have trouble making a viable business case to do it. For the price of one unit in space you could have at least half a dozen on the ground. If you're worried about intermittency, install some on-site storage, such as the liquid metal batteries [youtube.com] coming out next spring (with backing from Khosla Ventures). And if your're near the ocean, use a water-cooled solar concentrator to combine PV electricity generation w
Re:The 44.7% efficiency requires 297 suns (Score:5, Funny)
This means that they use mirrors to focus the light onto the panel.
I know just where to put them.
http://news.slashdot.org/story/13/09/03/0157256/building-melts-car [slashdot.org]
Re:The 44.7% efficiency requires 297 suns (Score:5, Informative)
They use Fresnel lenses, not mirrors : http://www.soitec.com/en/technologies/concentrix/components/ [soitec.com]
PS: I worked with Concentrix (now Soitec). Cool company.
Re:The 44.7% efficiency requires 297 suns (Score:4, Interesting)
Yawn...
Another day another solar cell breakthrough that wont see the light of day (see what I did there) for 10 years if ever.
Why is it none of these ever make it to manufacture. Typical solar panels have an average efficiency of 15%, with the best commercially available panels at 21%.
Yet we get a new announcement weekly.
Re:The 44.7% efficiency requires 297 suns (Score:4, Insightful)
It's not really efficiency that determines the profitability of solar cells. It's the ratio of Efficiency / $. These might be the most efficient ever produced, but they're likely substantially more expensive than the 15% variety (i.e. 3x more efficiency at 10x the cost).
Re: (Score:3)
Re: (Score:2)
Re: (Score:2)
It's not really efficiency that determines the profitability of solar cells. It's the ratio of Efficiency / $. These might be the most efficient ever produced, but they're likely substantially more expensive than the 15% variety (i.e. 3x more efficiency at 10x the cost).
The cheap ones are good for non-concentrating solutions, but the sweet spot for concentrator arrays is somewhere else. If you're using a 300x concentration factor, you only need 0.3 percent of the solar cell area. In that case, since the cell is only a small part of the cost of the solution, if increasing power output by a factor of three (due to increased efficiency) is accompanied by a less-than-threefold price increase, you've won.
Re:The 44.7% efficiency requires 297 suns (Score:4, Interesting)
Because as much as I look forward to someday powering my entire house with a handful of 90% efficient solar panels, I care a lot more about the cost per panel at present. If I can afford to pave a quarter acre with 10% efficient panels while these 40%+ ones would bankrupt me - Hey, guess which ones I'll just buy 4x as many of?
Re: (Score:2)
Re: (Score:2)
Who said anything about putting them on the roof? When I said pave a quarter acre with them, I meant it more-or-less literally... You wouldn't really need a quarter acre, of course - more like 1/40th of an acre - but if you have 50-100 1m^2 panels fencing in your yard, or off in that back corner overgrown with weeds anyway, or even acting as your driveway/sidewalk (obviously those last two would require panels a bit more durable th
Re: (Score:3)
Give credits to this company.
They have fields in Spain, USA & Israel (http://www.soitec.com/en/products-and-services/solar-cpv/our-references/) with about 25% of system efficiency.
This takes into account optical losses, cell efficiency, module efficiency, module mismatch, inverter efficiency, cable losses, etc etc...
It's not 45%, but it's twice as much as any other PV installation.
Nobody will ever achieve 44.7% system efficiency, but Concentrix does a pretty good job at implementing those cells in their
Re: (Score:2)
Re: (Score:2)
> Why is it none of these ever make it to manufacture
They've been in manufacturing for years. They've simply improved the design.
It's like someone made a faster car, and you use this to claim no one builds any cars.
Re: (Score:2)
Pulled them out of wiki [wikipedia.org], and Forbes [forbes.com] agrees, as do various [toptenreviews.com] review [sroeco.com] sites [1bog.org].
No consumer PV installations advertise 32% efficiency.
Re:The price & efficency of solar cells is irr (Score:4, Informative)
Some areas ensure you get real cash back for feed in back to the grid. Others have do not offer so much export cash to homes with solar.
City building/code regulations can also be costly in some areas.
http://freeingthegrid.org/ [freeingthegrid.org]
http://en.wikipedia.org/wiki/Net_metering#United_States [wikipedia.org] vs http://en.wikipedia.org/wiki/Feed-in_tariff#United_States_2 [wikipedia.org]
http://finance.yahoo.com/news/solar-panel-next-granite-countertop-161321343.html [yahoo.com]
http://www.fool.com/how-to-invest/personal-finance/home/2013/09/15/net-metering-how-a-little-known-policy-can-shave-h.aspx [fool.com]
When energy prices going up, you get a FIT, the cost of a solar install in your state is fair, your home has newer appliances... the pay back period is not so unaffordable over years.
Wrong (Score:5, Funny)
I find it pretty comic you're listing today's absorption rates as the reason solar "will never" (emphasis on the bolded word) be affordable. What website are you on right now? I wouldn't peg you for a technology enthusiast. Got news for you, bud: technology advances. Solar will become a dominant energy source. It's just a matter of when. You should stop watching cable TV; it's convinced you of silly things, sheltered you in petrol pipe dreams.
Re: (Score:2)
Though I think the original post is overblown, absorption rates are irrelevant. My suburban house and surrounding land has only X amount of area exposed to sunlight. Most of that is not in direct sunlight. Most of it is actually angled to one way or another or on the side of my house (which the local council would never let me blanket in solar panels unless they were literally invisible).
Even then, assuming we invent a perfect solar convertor, and blanket every square inch of my property, and chop down e
Re: (Score:2)
> which the local council
Hmmm, suspecting UK
> blanket in solar panels unless they were literally invisible
Do you mean like this? http://www.dowpowerhouse.com
> Even then, assuming we invent a perfect solar convertor, and blanket every square inch of my property, and
> chop down every tree casting a shadow, there's an absolute maximum of sunlight energy coming to my house and land
Indeed, and in, say, London that would be about 1MWh per meter per year. I strongly suspect that if you add up all the a
Re: (Score:2)
We already have free solar cells. They're called plants. When you burn wood, or make ethanol from cane sugar, you're using solar energy.
That's why IMHO the holy grail of power generation (other than fusion) is cellulosic ethanol. The vast majority of the solar energy plants collect goes into making cellulose. CO2 + H2O + energy => O2 + (CH2O)n. The (CH2O)n is sugar, which plants then string t
Re: (Score:2, Interesting)
Two years ago I had 10 square metres of solar power put on my roof. Total cost: £15000 (~$20000). These cells have produced 3400 kW/H of electricity over that period. I don't live in the tropics; Latitude ~53 deg north.
Last point: Solar cell prices have fallen over 35% during the last 2 years.
Not phenominal but not irrelevant either
Re: (Score:2)
I don't see your point at all.
I installed a 10kW system on my roof several months ago. Including (professional, by licensed company) installation and decent hybrid panels, it cost 18k Euro ($24k). It would have been 15k with cheaper panels back then, and now the prices have fallen another 20%.
It produces over 15MWh/y (I am not in Germany, however my roof does not have near optimal alignment, hence it could still be better), and the panels have an efficiency guarantee for 25 years. So a modest estimate (the
Re: (Score:2)
They used to say the same thing about desktop computers too.
Re:So what, nearly 4 watts per square metre? (Score:5, Insightful)
Sunlight at high noon directly overhead is close to 1000 watts per square meter. My neighbor's roof has panels about 2x4 ft (a bit less than a square meter) that are rated at 120 watts output each. Her rooftop array of just a dozen panels provided 100% of her consumption last year, per her net metering annual bill.
It's a very modest sized house, One bedroom, one bath, about 1000 square feet, but it is also a very modest sized array.
Re: (Score:2)