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Science Forum

  1. 21 Oct '13 17:07 / 6 edits
    http://phys.org/news/2013-10-cleaner-greener-cities-transparent-solar.html

    They work by being mainly transparent to visible light but absorb UV and i.r. light to convert some of that energy into electricity. This is not exactly a new idea but hopefully this will now become economic and be soon used widely.


    While on the subject of solar cells, here is another bit of good news:

    http://phys.org/news/2013-10-scientists-breakthrough-solar-technology.html

    "...In the near future, solar panels will not only be more efficient but also a lot cheaper and affordable for everyone, ...
    ...
    ....This next generation solar cell, made from organic-inorganic hybrid perovskite materials, is about five times cheaper than current thin-film solar cells, due to a simpler solution-based manufacturing process.
    ....
    Perovskite is known to be a remarkable solar cell material as it can convert up to 15 per cent of sunlight to electricity, close to the efficiency of the current solar cells, but scientists did not know why or how, until now....
    ....
    ...Perovskite-based solar cells have the potential to reach 20 per cent solar cell efficiencies...
    ..."

    -and perovskite is calcium titanium oxide with the chemical formula CaTiO3. Note that all three of those chemical elements it is made of are very common chemical elements in the earth's crust thus are all relatively cheap and readily available in large quantity.
  2. 22 Oct '13 16:03
    Some progress with plastic photovoltaics:

    http://phys.org/news/2013-10-low-priced-plastic-photovoltaics.html

    The progress in truly cost effective solar power always seems to me agonizingly slow and incremental but I think it would not be too many years now before we finally get there. Perhaps 10 years time?
  3. 22 Oct '13 18:39 / 1 edit
    Originally posted by humy
    Perhaps 10 years time?
    Don't know, but surely sooner than fusion power, or mass commuting by flying car.
  4. 22 Oct '13 19:54 / 1 edit
    Originally posted by humy
    The progress in truly cost effective solar power always seems to me agonizingly slow and incremental but I think it would not be too many years now before we finally get there. Perhaps 10 years time?
    Get where? Solar is already quite widespread, it is clearly already cost effective for some purposes. So how cheap do you want it to be?

    http://io9.com/solar-powers-epic-price-drop-visualized-510448484

    http://cleantechnica.com/2013/09/19/cost-solar-power-60-lower-early-2011-us/
  5. 22 Oct '13 21:14 / 8 edits
    Originally posted by twhitehead
    Get where? Solar is already quite widespread, it is clearly already cost effective for some purposes. So how cheap do you want it to be?

    http://io9.com/solar-powers-epic-price-drop-visualized-510448484

    http://cleantechnica.com/2013/09/19/cost-solar-power-60-lower-early-2011-us/
    Get where?


    I would say we want solar energy to become so cost effective that it would become virtually always cheaper during daylight hours to generate each joule of electricity via solar energy than via burning of fossil fuels -that is 'where'!

    Once that happens, I predict virtually every rooftop in the world will soon be covered with solar panels which would be unlikely to happen until solar energy becomes that cheap.
    And then, some time later (hopefully not too many years later ) , once the problem of making cost effective off-the-grid storage has been sorted (probably mainly by using huge off-the-grid batteries especially for this purpose ) and also the problem of electricity distribution has been sorted (by making a world-wide supergrid ) , I predict that solar energy (along with other renewables but I predict generally to a lesser degree ) would quickly completely replace fossil fuels for electric power generation.
  6. 22 Oct '13 21:31 / 5 edits
    Originally posted by Paul Dirac II
    Don't know, but surely sooner than fusion power, or mass commuting by flying car.
    I think so to. In fact, in the case of mass commuting by flying cars, I don't think that would ever happen! -it would be just too much of a health and safety nightmare (assuming people and not AIs will drive them! else might be able to eliminate human error and also make it safe enough ) and would never be nearly as energy efficient nor cost effective as certain other modes of transport.
  7. 23 Oct '13 06:40 / 1 edit
    Originally posted by humy
    I would say we want solar energy to become so cost effective that it would become virtually always cheaper during daylight hours to generate each joule of electricity via solar energy than via burning of fossil fuels -that is 'where'!
    Do you happen to know roughly what the cost per joule should be to achieve that?

    Once that happens, I predict virtually every rooftop in the world will soon be covered with solar panels which would be unlikely to happen until solar energy becomes that cheap.
    So are you saying that all the people who currently have solar panels on their roofs are running at a loss? (for people who live near access to grid energy).
  8. 23 Oct '13 08:41 / 6 edits
    Originally posted by twhitehead
    Do you happen to know roughly what the cost per joule should be to achieve that?

    [b]Once that happens, I predict virtually every rooftop in the world will soon be covered with solar panels which would be unlikely to happen until solar energy becomes that cheap.

    So are you saying that all the people who currently have solar panels on their roofs are running at a loss? (for people who live near access to grid energy).[/b]
    Do you happen to know roughly what the cost per joule should be to achieve that?

    I don't quite. I tried to get some stats on that but found it rather difficult to tease out the relevant info for that because you've got the huge complicating factor of the initial capital costs and how long it takes for that initial investment in that capital cost to pay for itself. I got:
    http://en.wikipedia.org/wiki/Cost_of_electricity_by_source
    which gives a rather complex picture but I think the gist I gather from that link is that the cost of solar would have to drop to very roughly half of whatever it is now before it becomes cheaper than fossil fuels generally.

    But then I found various websites that appear to logically contradict that above picture and are saying solar is already generally cheaper than fossil fuels! For example:

    http://theconversation.com/newsflash-solar-power-costs-are-falling-below-fossil-fuels-7215
    “...
    Many of the postings point to a brilliant solar or wind or geothermal future – but then fall back on an argument for subsidies to make up for the higher costs of the renewables.
    It can now be stated definitively that such arguments are out of date. Renewables in many cases are actually cheaper than their fossil-fuelled rivals. And the most important such case is that of solar photovoltaic cells – the cells that convert sunlight directly into electric power.

    ...the costs of solar PV cells are falling by around 45% per year.
    ...
    producing electric power from solar PVs should now be cheaper than producing power from stand-alone diesel generators …
    ...”

    So, I now just don't know for sure any more. But I think, surely, when the cost of solar power becomes, say, 70% percent less than whatever it is now, we will be definitely 'there'! But note that the above link says "the costs of solar PV cells are falling by around 45% per year. "! Well, if that continues, we could be 'there' in just two years time! ( -somehow I think that is rather optimistic )

    So are you saying that all the people who currently have solar panels on their roofs are running at a loss? (for people who live near access to grid energy).

    What! No. But, still, nevertheless, I believe the current cost of solar panels is the main reason why not virtually everyone are falling over themselves to have them put them on their roofs! All that I am saying is that once that cost goes down to a point that virtually all people can then have solar panels installed to completely cover the roof and make a relatively 'quick' return for that investment (lets say, for the sake of argument, it then takes less than a year for the solar panels to pay for themselves) thanks to solar becoming universally cheaper everywhere than electricity from fossil fuels (although, as I indicated earlier, this just might already be the case! But not sure about that at all ), then the option of putting solar panels would become a non-brainer (because then, unless you don't use electricity, you would usually have to be completely stupid to NOT have them put on your roof! ) and then, because of that, I predict just about everyone would be falling over themselves to have them put them on! You see, at the moment, for may people it IS questionable whether it would be a worth while investment for them to have them put on their roofs because, for many people's homes in many parts of the world, it takes a rather long time (years or even decades in some cases ) before the solar investment pays for itself and that puts people off (including myself ) because they wonder is it worth the bother for them because it is just a bit TOO long-term for most people.
  9. 23 Oct '13 09:00 / 1 edit
    Originally posted by humy
    But then I found various websites that appear to logically contradict that above picture and are saying solar is already generally cheaper than fossil fuels!
    The second site I posted earlier claimed the cost of solar had dropped by 60% in since 2011. So its clear that the date of any references will matter.

    What! No. But, still, nevertheless, I believe the current cost of solar panels is the main reason why not everyone or at least most people are falling over themselves to have them put them on their roofs!
    The problem is that for solar, there is an upfront investment cost both in terms of capital and time/effort. Most people already have installed power, so switching to solar takes effort and some amount of risk (finding the right contractor etc).
    With utility power on the other hand the utility covers the investment costs (with government or investor help).
    Where solar has been spreading the most is where companies or government assist with the initial investment and risk. For example companies that install the solar panel for you then charge you per month based on usage.

    (lets say, for the sake of argument, it then takes less than a year for the solar panels to pay for themselves)
    But the initial installation lasts for much longer than that, so you are essentially saying that solar must be many more times cheaper than fossil fuels. Meanwhile you are not requiring the same of fossil fuel companies. They make investments over decades.

    I must also add that where I come from, Zambia, we have hydroelectric power which is relatively cheap (about half the price of what it is here in Cape Town), and we have much higher costs for solar due to the importation costs. Nevertheless, its probably worth looking into whether or not its cost effective.

    Here in Cape Town, solar water heaters are quite common. I rent a flat so I don't have the option to use solar.

    I have also noticed the traffic cameras along the highways have little solar panels and little wind turbines.

    I must also add that solar is actually being installed worldwide at an incredible rate (approaching Moore's law.)
  10. 23 Oct '13 09:13 / 5 edits
    Originally posted by twhitehead
    The second site I posted earlier claimed the cost of solar had dropped by 60% in since 2011. So its clear that the date of any references will matter.

    [b]What! No. But, still, nevertheless, I believe the current cost of solar panels is the main reason why not everyone or at least most people are falling over themselves to have them put them on t ...[text shortened]... hat solar is actually being installed worldwide at an incredible rate (approaching Moore's law.)
    I have also noticed the traffic cameras along the highways have little solar panels and little wind turbines.

    I have just noticed the other day that there is now a huge wind turbine in my line of sight from my house window on the mountain that wasn't there before ( I am saying the turbine wasn't there before, not that the mountain wasn’t there before ) . I know of the phenomenon of wind turbines attracting more wind turbines so I expect to soon see a lot more of them in my area and don't have to be told that there will be more coming. Unlike many people in this country, I don't oppose them appearing on my back yard (unless one is literally put in my yard ) -I am more than willing to look at the wider picture of the greater good and I just do not understand why so many other people aren’t. I think the massive opposition of wind turbines by so many of us brits is just stupid.
  11. 23 Oct '13 10:27 / 1 edit
    http://www.energysavingtrust.org.uk/Generating-energy/Choosing-a-renewable-technology/Solar-panels-PV/Free-solar-PV-offers

    Apparently in the UK there are companies that will install PV for you and give you free electricity off it in exchange for also selling some of the generated power to the utilities.

    Here in SA we can rent solar water heaters:
    http://www.solarent.com/