back to article Solar sandwich cooks at 40 per cent efficiency

Australian solar trailblazer Professor Martin Green's group at the University of New South Wales is claiming a world record in solar efficiency, and this time it's not the usual half-per cent incremental improvement. The Australia-US Institute for Advanced Photovoltaics that Green directs says its combination of off-the-shelf …

  1. Steven Marsh

    Uh, so let me get this straight...

    Stacking some panels, ok, stacking THREE panels, adding a mirror, and redirecting excess light to a FOURTH panel does not seem like a 40 percent capture rate.

    Its more like ( 40 / 4 ) = 10 percent capture rate....

    Because the reason the capture rate matters is because of the cost of the silicon, and in this case, you have 4 'effing panels!!!

    So, thats four times the cost, plus the cost of the mirrors...

    This is a non-story....

    1. Anonymous Coward
      Anonymous Coward

      Re: Uh, so let me get this straight...

      There are multiple kinds of efficiencies possible. Watts/m^2 is one, and that is what this increased. $/watt is another, and that is not helped by this.

      So it may not be useful on your roof where $/watt matter, but on a satellite or other area limited circumstance $/watt is of little consequence while watts/m^2 is a very big deal indeed.

      Also, if you used mirrors to focus the sunlight so you needed 10% of the panel area you previously did, it might turn out cheaper in $/watt to use 3 panels and a mirror after all...

      1. BristolBachelor Gold badge

        Re: Uh, so let me get this straight...

        In space you can't use silicon cells - they degrade too quickly because of the radiation. Satellites currently use "Tripple Junction" cells made from Galium Asenide. The 3 junctions each capture photons of different wavelengths which increases the efficiency, so similar to what was done here, but without mirrors. They are currently in the ~30% efficiency level for cells (once you add physical structure, harness, prptection etc. it drops a litle as a system. If interested look here at some examples Azure Space

        The article mentions solar thermal generation efficiency, but fails to mention what efficiency the new system has at storing the power so that you can use it to light your house after the sun has set. This built-in energy storage is what makes solar thermal more flexable

    2. Anonymous Coward
      Anonymous Coward

      Re: Uh, so let me get this straight...

      "Because the reason the capture rate matters is because of the cost of the silicon, and in this case, you have 4 'effing panels!!!"

      In a production scenario you would be using multiple layers, not multiple panels. The cost of creating the silicon layers (particularly with emerging technologies like spray coating or printing the layers) is not really going to be an issue.

      The two real challenges I see are:

      1) Watts per square metre. The article mentions utility scale arrays in China. But if you're going for roof mounted arrays (which usually make sense in most expensive land locations) does this design have a significantly higher area energy density than the alternatives? If not then it's going nowhere - a bit like magnifying solar collectors, which increase efficiency, but are still constrained by the available collector size. Assuming this is either not a problem, or can be overcome, we arrive at the second challenge:

      2) In their pell mell rush to foist renewables on the world, politicians in the EU and most anglophone countries have used subsidies to carpet the prime roof space with what will soon be technically obsolete low efficiency panels, being rewarded for may years hence by over generous feed in tariffs. This is what happens when government panics, and chooses to subsidise doing something for the sake of it, rather than putting money into proper R&D.

      1. Amorphous

        Re: Uh, so let me get this straight...

        Average panel lifespan is about 20 years. All those roof top panels have about another 10 years before they need replacing, which is about the time required to commercialise this new tech for the consumer. So the jump to rooftop PV was probably the right thing to do at the time, and has increased investor confidence that made this kind of innovation possible.

        You are right that over-generous feed-in tarrifs do not foster trust from skeptics and anti-government types, but neither do over-generous subsidies and tax breaks to the fossil fuel industry.

    3. Anonymous Coward
      Anonymous Coward

      Efficiency % important for niche applications

      Meanwhile, $/watt is all that matters.

      1. Anonymous Coward
        Anonymous Coward

        Re: Efficiency % important for niche applications

        Recently opened solar farm in California. $2.5B for saving 377k tons CO2 per year. That's $6.6k per ton of avoided CO2 per year. If we need 30 billion tons CO2 per year reduction, that approach would cost $200 trillion. Roughly all the wealth on Earth. Maybe we could get payment terms and spread it out over a few million years.

        This is what happens when you let naïve, innumerate environMentals run things. They should hire a skeptical thinker with some Grade 10 math skills; even a "denier" would be more effective than the lunatics running the show now.

        1. squigbobble

          Re: Efficiency % important for niche applications

          Yes but you don't have to buy a new $2.5B plant every year. Assuming a lifespan of 20 years (and also ignoring the ongoing maintenance 'cos I've no idea how expensive that would be, except that it won't be $2.5B/yr) that brings it down $330/ton of avoided CO2 which is still pretty eye watering though it seems to be in the ballpark for the retail price of bulk coal in the UK.

          1. JeffyPoooh
            Pint

            Re: Efficiency % important for niche applications

            @squigbobble et al

            The unit under discussion is: **TONS (or tonnes) of avoided CO2 PER YEAR**

            It's already including the 'per year' !!!!!!!!!!

            The $2.5B solar farm gives us 377,000 of them.

            That's $6,600 each.

            We need 30,000,000,000 (30 billion) of them.

            That's $200,000,000,000,000 ($200 trillion).

            That's nearly ALL THE WEALTH ON EARTH.

            The fact that you screwed up simple math and the fact that my post was heavily down voted proves my point.

            Most environMentals are innumerate and their ignorance of trivial math and science *is* a greater threat to the world than the deniers.

        2. dncnvncd

          Re: Efficiency % important for niche applications

          Agree with your math as to per annum cost and not 20 year amortized cost. However, this cost is expected to be borne by taxpayer subsidies and mandated carbon credits. So this is more about money than saving the Earth. If it were about people and the Earth, building codes would require new construction make maximum use of on-site solar and wind generation, In such a case, DC electricity could be used locally while transmitting excess generation via an inverter as AC to the grid. Haven't done a patent search, but I recall a similar layered panel design in the "70's. Individual solar cell efficiency at 16% or commercial at 33% would seem to indicate an efficiency loss if a battery of cells achieves 40%. As for the mirrors, it wasn't clear if that was for focusing light or heat generation. Neither one is practical for household installations.

  2. Sampler

    Professor Green?

    Has he been to deed poll by any chance?

    1. Scoular

      Re: Professor Green?

      Martin has always been Martin Green, since before the Greens in fact.

    2. Paul Crawford Silver badge

      Re: Professor Green?

      It was done by Professor Green with a telescope in the Observatory!

      Or was it by Miss Scarlet with a strap on in the basement?

      Any clues?

      1. tony2heads

        Re: Professor Green?

        Mrs White with the biodigestion plant in the back yard

  3. Paul J Turner

    Warning Words

    "Focused Sunlight", "Mirror(s)". If it isn't about 400W for 1 square metre of sunlight direct from the sky, get lost.

    1. Anonymous Coward
      Anonymous Coward

      Re: Warning Words

      You forgot to add that it needs to be average for a 24 hour period under conditions comparable to a blizzard in Reykjavik during the Winter Solstice. Unless it can perform self-sufficiently even under worst-case scenarios, why bother?

      1. Thought About IT

        Re: Warning Words

        Why bother? Well, if it works for 12 hours a day, that could work out at a 50% reduction in fossil fuel use. Of course, if you're denying that the consequent CO2 emissions are having a damaging effect on the climate, I can see why that question might cross your mind. Otherwise, the answer is obvious!

        1. NumptyScrub

          Re: Warning Words

          Why bother? Well, if it works for 12 hours a day, that could work out at a 50% reduction in fossil fuel use. Of course, if you're denying that the consequent CO2 emissions are having a damaging effect on the climate, I can see why that question might cross your mind. Otherwise, the answer is obvious!

          Apparently around 50% of the experienced warming may be due to a 60 year cycle of ocean currents trapping and then releasing heat (accelerating the warming for 30 years, and then decelerating warming for the next 30 years). This would suggest that some of the assumptions made regarding the relative effects of certain mechanisms (like the actual amount of warming due to the greenhouse effect of atmospheric CO2) may be in error, and should be revisited.

          It would certainly have an effect on the numbers if, for instance, the overall warming due to atmospheric heat capture (including the effect of increased CO2) is only 50% of that measured increase, and stored heat in the deep sea is responsible for the other 50%, which would appear to be what that study is suggesting. And it would have to be around that 50% figure, if the cycle reversing (and the current switching to storing rather than releasing heat) can completely negate any increase (like the 10+ year hiatus we are experiencing) even though CO2 emissions are continuing unabated.

          Of course these are all still theories, and only time will allow us to test predictions and further refine them based upon the feedback of subsequent measurements. But it does shed some small doubts upon the "obviousness" of the role atmospheric CO2 is playing on global temperatures. It does not appear to be as large an effect as some people have assumed, if it can be entirely negated by the action of polar currents.

          1. Thought About IT

            Re: Warning Words

            @NumptyScrub, you've completely misunderstood that report. Wilfully?

          2. Ciro

            Re: Warning Words

            "Apparently around 50% of the experienced warming may be due to a 60 year cycle of ocean currents trapping and then releasing heat (accelerating the warming for 30 years, and then decelerating warming for the next 30 years). This would suggest that some of the assumptions made regarding the relative effects of certain mechanisms (like the actual amount of warming due to the greenhouse effect of atmospheric CO2) may be in error, and should be revisited.

            It would certainly have an effect on the numbers if, for instance, the overall warming due to atmospheric heat capture (including the effect of increased CO2) is only 50% of that measured increase, and stored heat in the deep sea is responsible for the other 50%, which would appear to be what that study is suggesting. And it would have to be around that 50% figure, if the cycle reversing (and the current switching to storing rather than releasing heat) can completely negate any increase (like the 10+ year hiatus we are experiencing) even though CO2 emissions are continuing unabated.

            Of course these are all still theories, and only time will allow us to test predictions and further refine them based upon the feedback of subsequent measurements. But it does shed some small doubts upon the "obviousness" of the role atmospheric CO2 is playing on global temperatures. It does not appear to be as large an effect as some people have assumed, if it can be entirely negated by the action of polar currents."

            I always find these sorts of arguments against acting on the (fairly well supported) theory that we're responsible for global warming rather odd.

            If you were standing in a field, near a gate, with a bull charging towards you, and you had two theories as to why:

            a) he's enraged by your red jacket and wants to charge you

            b) he's planning on running past you to the exit

            Would you stand still and wait for further clarification, or would you hastily ditch the red jacket and move out of the road?

        2. Ian Michael Gumby
          Coat

          @Thought about it.... Re: Warning Words

          Well if you really thought about IT... you'd have realized that these plants are frying any bird that happens to fly through the area... And that there's something more efficient.

          Its called Nuclear Energy.

          And there are now later generation plants that are very safe along with potential disposal site(s) available... now that Harry Reid is no longer in a position to stop votes and shut down congress for doing anything... We can see this move forward. Unfortunately it doesn't mean net new power plants, but the clean up of spent fuel from existing plants that had been forced to come up with temporary storage for 20 years of fuel thanks mainly to Reid stonewalling things.

          And if you have to invest in R&D, look at fusion over solar.

          Just saying... Mine's the lead lined jacket as I scamper down to maintain my micro reactor capable of powering an aircraft carrier or 40K homes.... (And no CO2 emissions, just steam...)

        3. JeffyPoooh
          Pint

          Re: Warning Words

          "Well, if it works for 12 hours a day, that could work out at a 50% reduction in fossil fuel use."

          With Math skills like this --^ , we are doomed.

      2. Anonymous Coward
        Anonymous Coward

        Re: Warning Words

        "needs to be average for a 24 hour period under conditions comparable to a blizzard in Reykjavik during the Winter Solstice. "

        Not really no. The most sensible plan currently seems to be for a number of solar stations distributed near the equator, connected to a global HVDC network. There'd be enough energy hitting those locations to generate the entire world's energy needs, 24/7. Some local generation might be desirable in addition to a global system, but it's not critical.

      3. Anonymous Coward
        FAIL

        Re: Warning Words

        "...blizzard in Reykjavik during the Winter Solstice...."

        Why?

        Iceland is one of the biggest users of "green" energy out there, with most of it coming from geothermal and hydro power.

        So lets flip your argument, "so unless you can use hydro damns in the middle of the Sahara, then why bother."

        See how much of a dick you look now?

        1. This post has been deleted by its author

          1. HMB

            Re: Iceland

            I got the wrong end of the stick with my previous post, which is below. Sorry guys. I re-read the thread and I see what happened. I jumped to the conclusion that geothermal was being advocated as a cure all and should have read the thread more carefully.

            FYI lost all faith, I changed my downvote into an upvote.

            And when hot springs and geysers start popping up all over the earth in a freak unexplainable incident that makes the earth's crust as thin everywhere as it is in the geographically extraordinary Iceland, your argument will hold water.

            Geothermal and hydro have long been economically viable methods of power generation that are already pretty much maxed out. Despite being one of the most viable renewable resources, hydro is being resisted by environmental campaigns too. See the film 'Damnation':

            http://damnationfilm.com/

            Just to be clear about my position. I'm all for subsidised renewables up to say 5% of total demand to encourage development of the technologies, but beyond that they must compete economically because otherwise you're simply denying the poorest access to electricity, which is a real dick move.

            1. deadmonkey

              Re: Iceland

              "compete economically"?

              Erm, you mean how the existing technologies exist without government subsidy? (eg. how we pick up the tab for decommissioning nuclear power plants etc).

            2. Psyx
              Joke

              Re: Iceland

              " otherwise you're simply denying the poorest access to electricity, which is a real dick move."

              Quite. They should only remain deprived of drinking water and food.

            3. Saigua
              WTF?

              Re: Iceland

              No, we must go simpler! Passive DOSing is denying we exist and can only be stopped by concentrated plumbing of sun pumps.

              Simpler! Denial slack must be done faster by Fabry-Perot up swipe capture instead of active IR. Having that detection in place means installing Green's stack.

              After the licensing art's out.

        2. Charles 9
          FAIL

          Re: Warning Words

          FAILURE FAILURE.

          REASON: Bad analogy.

          At least hydro dams are pretty consistent. Bad weather only affects its output marginally barring a genuine disaster.

          Solar has a problem in that department, and even solar thermal has a limited area of practicality (all the ones I know of are in southern deserts). Sunlight gets less consistent the further north you go. I chose Reykjavik because it happens to be just south of the Arctic Circle. That's about as far north as you can go before you go into the six-month day/night cycle (as in six-month days and nights). The winter solstice is the shortest day of the year up north, so imagine how little sunlight a place like Iceland would get that day. Furthermore, the sunlight's at a shallow angle, weakening its strength further.

          Solar is just not practical for a sizable chunk of the world, and if you try to spread it around or go into space, you now have international relations to contend with, not to mention political chess (or worse, sabotage--think solar collector turned killer space maser).

    2. JeffyPoooh
      Pint

      Re: Warning Words

      The only efficiency worth discussing is watts per dollar, or dollars per watt.

      Capture efficiency in % might help, but only if it's cheap. If it's expensive, then it only helps with niche applications such as satellites.

  4. Anonymous Coward
    Anonymous Coward

    Upon reflection...

    ..I see that while the article claims a big jump in efficiency, quoting the numbers 40% vs. 22%, it's not emphasized that the 40% is photovoltaic, very different than the steam systems with their 22%. Turns out the Australian article linked talks about other competing PV cells having 36% efficiency at the moment.

    Maybe a 4% PV efficiency jump is news, but it's even better when it seems to be 18%, right? Sure would make all the (probable) added expense easier to accept.

    And this talk about filters, which I assume restricts light on each panel to what it likes, means they can receive more light without burning up, and would imply more mirror area to compensate for the filtering effects. More mirrors = more cost. I wonder where the break-even point lies (I mean the one with subsidies included).

    1. Hero Protagonist

      Re: Upon reflection...

      <pedant>

      An increase from 36 to 40 percent is actually an 11% increase: (40-36)/36

      </pedant>

  5. Anonymous Coward
    Anonymous Coward

    40 per cent efficiency - we progress

    Meanwhile: LNP Government at 40 per cent popularity (and falling) actively killing the renewables industry in Aus.

    1. Atomic Duetto
      Angel

      Re: 40 per cent efficiency - we progress

      Welcome to the starship Team Australia. Please do not be alarmed by anything you see or hear around you. You are bound to feel some initial ill effects as you’ve been rescued from certain death at an improbability level of two to the power of two-hundred and seventy-six thousand, seven-hundred and nine to one against - possibly much higher. We are now cruising at a level of two to the power of twenty-five thousand to one against and falling, and we will be restoring normality as soon as we are sure what is normal anyway. Thank you. Two to the power of twenty-thousand to one against the LNP being booted out and falling…

  6. Faux Science Slayer

    Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

    Photocells do NOT create energy, they release a loosely held, outer shell electron by solar EMR excitation, which exits the cell and never returns. PV produces 1 watt per square foot at 1.5 volts of Direct Current, maximum for less than six hours per day. NO photocell can produce the massive amounts of energy to mine, refine, produce and distribute photocells, and in fact produce only a tiny fraction of this original investment energy in their service lifetime. Maximum limit on this molecular erosion process is twenty years on Earth, but half that in space due to longer daily exposure. Magnifying the 'daily output' reduces the 'fixed output' lifetime. Wind and biofuels have similar, net energy, life cycle defects. We have been systematically LIED to about everything.

    Please read...."Green Prince of Darkness"....at the FauxScienceSlayer website for PV analysis.

    1. Duncan Macdonald
      FAIL

      Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK ! -IDIOT

      The electrons leave the cell on one terminal and then re-enter on the other terminal - the thing called an electric current is a flow of electrons. It takes under a microsecond for an expelled electron to be replaced.

      Even low grade solar cells can manage over 10 watts per square foot in direct sunlight.

      Commercial solar PV installations in suitable locations produce far more electrical energy over their lifespan than was needed for their construction.

      Try reading websites where the contributors have an average IQ above 50.

    2. MrXavia
      Facepalm

      Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

      Also did you know the earth is flat?

    3. HMB

      @Faux Science Slayer

      I don't think solar is a scalable, large scale, economic answer to the world's energy problem, but I still winced when I read some of that comment. I still believe it needs development and investment to see if one day it will cut it, economically speaking.

      Then I went back through your comment history.... Good lord!

      Have you changed your mind about Neil DeGrasse Tyson being a sock puppet?

      People might have unrealistic expectations about solar, but you need to chill out , raise the tone and intellectual integrity of your argument and be open to listening to the other side of the argument.

    4. Anonymous Coward
      Anonymous Coward

      Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

      Correct. Nuclear power is the only zero carbon power source capable of supplying sufficient energy for the industrial economy.

      And before the commentards wail 'safety' - Coal has killed more people then nuclear power.

      The next argument will be 'cost'. Tell me this - what do you think the economic cost will be when the current end of life power stations fail or the gas gets cut off from the Soviet block.

      You'll not be laughing when the rolling brown outs occur and you wished they'd built some nuclear capacity.

      1. Roland6 Silver badge

        Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

        Correct. Nuclear power is the only zero carbon power source capable of supplying sufficient energy for the industrial economy.

        But that does ignore the rather large amounts of carbon released in their construction...

      2. Anonymous Coward
        Anonymous Coward

        Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

        "...Nuclear power is the only zero carbon..."

        Concrete production emits a great deal of CO2. Have you seen a nuclear reactor? They take a decade to build and cost billions. All that emits CO2.

        Uranium doesn't mine itself. Think about the supply chain. Trucks. Bulldozers. Refining.

        It's not zero. I'll grant you that it's low, but "zero" is BS.

        BS like claiming that they're online 100%. Actual lifetime On fraction might be 75%.

        1. Nightkiller

          Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

          If anything, the cost to build a renewable infrastructure is just as bad. The equivalent levels of carbon emitted would practically cancel each other out. Benefit? Running an industrial economy versus a hunter-gatherer one.

          1. Charles 9

            Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

            "If anything, the cost to build a renewable infrastructure is just as bad. The equivalent levels of carbon emitted would practically cancel each other out. Benefit? Running an industrial economy versus a hunter-gatherer one."

            Don't renewables rely a lot more on harder-to-obtain materials like rare earths? Meaning they take an additional toll in the extracting and/or refining processes?

            1. Roland6 Silver badge

              Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

              >Don't renewables rely a lot more on harder-to-obtain materials like rare earths?

              Suspect you may be confusing simple low tech renewables with the more sophisticated high tech methods being used and proposed to enhance output. So for example solar thermal is relatively low tech, whereas high efficiency photovoltaic is definitely high tech and requires rare earths. But you do make an important point in that it is easy to get carried away by the tech and miss the fundamental rationale behind what we're trying to do...

        2. Charles 9

          Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

          "Concrete production emits a great deal of CO2. Have you seen a nuclear reactor? They take a decade to build and cost billions. All that emits CO2."

          And how much concrete is needed in a modern baseload coal or oil plant? Here's a thought--what about the dams needed for water storage or hydro power?

      3. Jason Bloomberg Silver badge
        Childcatcher

        Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

        And before the commentards wail 'safety' - Coal has killed more people then nuclear power.

        I am not disagreeing with you but the nuclear naysayers will point to the potential for harm being far, far greater than coal or anything else.

        No scientist worth their salt would ever say nuclear power is completely safe which always leaves open the possibility that it could all go catastrophically wrong. That fear of "could" ingrained in the paranoid is a near impossible hurdle to overcome; they simply always see the risk as too high.

        1. LaeMing

          Re: Coal

          Don't forget all the radioactive material released by burning coal - far more than all the world's nuclear plants have ever emitted into the atmosphere!

          (Yes, coal naturally contains trace amounts of radioactive materials which don't burn, and so go up the chimney).

      4. Anonymous Coward
        Anonymous Coward

        Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

        Yeah.

        I once got some coal dust stuck in my boot!

        Darn near ruined my sock.

        Unconstrained nuclear fuel on the other hand....

    5. PassiveSmoking

      Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

      Then why are there satellites with solar panels that have been up there for decades? The solar panels on the ISS still function and some of them have been up there since 1998. Furthermore they're riddled with holes from strikes with micrometeors and other space junk. If they still work in space after nearly 20 years while shot full of holes I think you might be underestimating them.

    6. Sheep!

      Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

      "Faux Science Slayer" - so you are a fake at slaying science? NOW your post makes sense!

    7. GrumpenKraut

      Re: Photovoltaics is a one time, one way molecular erosion PARLOR TRICK !

      Looked at your "FauxScienceSlayer website" ...

      Jeeeesus, the stupidity!

  7. kmac499

    That's why I'm waiting;

    More power to Prof Green or should that be from Prof Green

    I fully expect to have some PV on my roof within 5-10years at a much higher efficiency than is available today, which is why I haven't spent 5-10k on current panel tech.

    I also expect it to be part of integrated system where it handles the baseload of the house ( all those little red standby/charging LEDs need feeding) The Excess power to pre heat the water feed for a combi boiler and if there is a any left flog it back to the grid.

    1. Anonymous Coward
      Anonymous Coward

      Re: That's why I'm waiting;

      same here, I really want Solar PV, but I need high efficiencies due to trees and other obstructions preventing direct sunlight at times of the day....

      1. Michael Wojcik Silver badge

        Re: That's why I'm waiting;

        I really want Solar PV, but I need high efficiencies due to trees and other obstructions preventing direct sunlight at times of the day

        You might try finding some like-minded folks in your area and establishing a co-op that can purchase a more suitable site. If you live in an area where the power company will let you run the meter backwards, you just have them install a line and a meter at your site, then divvy up the payback among the co-op members. (Probably you don't want to try to get permission to run your own grid, unless you live way outta town.)

        Or there might be commercial alternatives. For example, the local power company in Taos has a "community solar" program; they've put up some panels in a suitable location and customers can buy shares in them to offset their ongoing electricity bills. I haven't investigated to see whether the terms make economic sense (and of course for each customer there's the question of estimating the value of intangibles), but as a scheme it has certain advantages over putting panels on the roof of your own house.

    2. Roland6 Silver badge

      Re: That's why I'm waiting;

      >I fully expect to have some PV on my roof within 5-10years at a much higher efficiency than is available today, which is why I haven't spent 5-10k on current panel tech.

      Personally, I would suggest that now is a good time to get in: with good PV panels giving around 20% efficiency and the government scheme giving a payback on installation costs/investment of around 10% per annum, on top of your savings from reduced electricity bills, plus there is only one way for energy bills to go, and that is up, you could well be in profit within 10 years and hence pay for the new panels out of your profits.

      In 5~10 years the PV industry will have settled down, just like double glazing and other major home improvements and the government incentives will have either been withdrawn or vastly watered down as the number of PV installations become the norm.

  8. Anonymous Coward
    Anonymous Coward

    It is not just about the number of individual panels used to generate the power. In my part of the world a sizable minority of domestic houses have 8-15 panels installed over their north-facing roofs. A more efficient design means that the area of the roof needed to produce a KW of solar power is smaller so there is more suitable roof space is available to mount more solar panels.

  9. wiggers

    0% efficiency...

    Between sunset and sunrise. Need to factor in a few AA rechargeable batteries...

    1. Anonymous Coward
      Anonymous Coward

      Re: 0% efficiency...

      To be fair... At least night time is predictable, and typically lower demand.

      Comparison. Nuclear is often presented as continuously producing power. In fact, the reactor needs to be shut down once in a while, and then they often find cracks that require 3 years unexpected downtime. It's only 100% when built in groups of reactors, like they do in Ontario.

      Point Lepreau is a single reactor. Under construction 1975-1983. Operating until 2008. Offline until 2012, on since. 39 years, about 70% Up Time. Argue all you want, it's not 100% by any stretch. Still good, just not 100% unless built in groups.

      1. Charles 9

        Re: 0% efficiency...

        "To be fair... At least night time is predictable, and typically lower demand."

        Depends on the location. Down south in the summer with long days, yes, because most of the energy is used in the day with climate control. But up north, in the winter, not only are days short (meaning more lights), but it's cold (meaning more electricity used for household heating and night storage).

    2. Hans 1
      Boffin

      Re: 0% efficiency...

      Go over and see the battery tech used in Teslas ... slightly better watt/cm3 than aa accus, if you ask me. Note, however, that that is beside the point. Having an alternative to nuke power is always good, especially if it allows distributed energy production.

      I assume they did not implement the recent findings of the Dutch team, otherwise that would mean another tenfold increase in efficiency is to be had - I assume they did not, since they were using commercial grade kit, and kit using the Dutch team's findings has yet to be mass-produced.

      I told you, there is a lot of room of improvement in this tech, sad, really, that there is no proper R&D funding.

      Mate of mine pays no leccy, the panels he put up 2 years ago have "paid for themselves" already, he has hectares of land, wants to build an industrial-sized photo-leccy plant, however, the local powergrid cannot stand that - I told him to start small, then expand.

      1. Michael Wojcik Silver badge

        Re: 0% efficiency...

        I assume they did not implement the recent findings of the Dutch team, otherwise that would mean another tenfold increase in efficiency is to be had

        "another tenfold increase in efficiency"? I'm trying to figure out what that might mean. From 40% to 94%? I have to admit that I'm just a little dubious.

    3. Terry Barnes

      Re: 0% efficiency...

      "Between sunset and sunrise. Need to factor in a few AA rechargeable batteries..."

      Or just network power in from somewhere the sun is still shining. At any given moment in time there is enough solar energy striking the earth to make powering the entirety of humanity's needs, including travel, a trivial undertaking.

      1. Charles 9

        Re: 0% efficiency...

        "Or just network power in from somewhere the sun is still shining."

        If they're willing to part with the power they get at that time. But that would require getting the world's nations to cooperate. Pardon me if I place my bets on a curling match in the seventh circle occurring first.

  10. earl grey
    Trollface

    So your Twatts are not the same as your Swatts

    T (Triple layer) of course...

  11. JeffyPoooh

    "Investment" represents embodied resources

    If you're making massive 'investments', then you are causing the extraction and expediture of massive amounts of resources. Example, Mongolian brown coal to power the factory in China that is making your subsidized solar panels.

    If the installation of an expensive and heavily subsidized solar farm makes you feel all warm and 'green', then you might want to recheck your math. It's very likely your decisions were environmentally suboptimal.

    1. Amorphous
      Thumb Up

      Investment mix - Death Spiral

      Your comment is a case of the perfect being the enemy of the good.

      I see the future being more a mix of energy sources: Renewables (Solar PV, Hydro, hot rocks, power tower, etc), along with traditional energy sources (nuclear, and coal). The mix will shift towards renewables over several decades as the technology develops.

      I've bought a couple of small panels for my roof. They are current "suboptimal" tech, but they do take the edge of the airconditioning bill for hot Aussie days in summer (and winter for that matter). They are easy to install and remove, and just plug into the wall socket (usually just to power the fridge). So when we move house we can take them with us.

      Slowly but surely, the grid power prices are creeping up in Oz as more people install PV and use less grid (thereby forcing them to raise prices to cover distribution costs). This makes is even more economical for rooftop solar PV and so the cycle repeats in a "death spiral" for grid power.

      I'll be adding more PV to take advantage of new tech, just a couple of panels at a time, over the coming decade or so.

  12. Paul J Turner

    This looks more like it

    http://www.technologyreview.com/news/533331/chip-making-tools-produce-ultra-efficient-solar-cells/

    Soitec, a French manufacturing company, says it has used techniques designed for making microprocessors to produce solar cells with a record-setting efficiency of 46 percent, converting more than twice as much sunlight into electricity as conventional cells.

    There had better not be mirrors involved!

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