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Solar Power Becoming More Affordable 355

Posted by Zonk
from the juice-from-spaaaaace dept.
prostoalex writes "With both startups and large companies such as Boeing working on solar power, the technology is becoming more affordable, MIT Technology Review says. Solar power concentrators are all in rage now: 'The thinking behind concentrated solar power is simple. Because energy from the sun, although abundant, is diffuse, generating one gigawatt of power (the size of a typical utility-scale plant) using traditional photovoltaics requires a four-square-mile area of silicon, says Jerry Olson, a research scientist at the National Renewable Energy Laboratory, in Golden, CO. A concentrator system, he says, would replace most of the silicon with plastic or glass lenses or metal reflectors, requiring only as much semiconductor material as it would take to cover an area the size of a typical backyard. And because decreasing the amount of semiconductor needed makes it affordable to use much more efficient types of solar cells, the total footprint of the plant, including the reflectors or lenses, would be only two to two-and-a-half square miles.'"
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Solar Power Becoming More Affordable

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  • by Nom du Keyboard (633989) on Friday November 10, 2006 @12:45PM (#16794872)
    Solar Power Becoming More Affordable

    This headline can be recycled and reused into perpetuity. Chances are with continuing advancements it will always become more affordable than it was last week, month, year, decade, or century.

    But when will it become truly affordable for the masses? That's what most of us want to know. Wake me when it's time to disconnect from the petroleum/nuclear fired grid.

    • by mcrbids (148650) on Friday November 10, 2006 @12:57PM (#16795088) Journal
      But when will it become truly affordable for the masses? That's what most of us want to know. Wake me when it's time to disconnect from the petroleum/nuclear fired grid.

      It's already happening in California. This deal is huge. It's between 300 and 900 Megawatts. [signonsandiego.com] And what's even more remarkable is that there is no federal or state funding for this project - not even a subsidy or tax break!

      The solar electricity is simply profitable. Watch this closely.

      Another interesting run is the Solar Tower project in Australia [enviromission.com.au]. I'm really excited by this one! Once built, the operating costs drop to near ZERO.

      What few people realize is how much the price of electricity varies. So go get your utility bill. Call the nearest solar energy installation guys. You may find that it's profitable RIGHT NOW to put solar cells on your roof!
      • by Martin Blank (154261) on Friday November 10, 2006 @01:26PM (#16795498) Journal
        The solar electricity is simply profitable.

        Not without tax breaks, it's not, at least for older tech. The Stirling generators that are intended for the SDG&E project (and which are also planned for a 500MW facility near Victorville) may change that, but we'll have to see how they handle the weather conditions here (as opposed to New Mexico) over the long term. And while the deal may be huge in terms of solar, it's really not that large when put in perspective with other plants, where 500MW-600MW plant construction is not terribly uncommon.

        The solar tower is interesting, but it's been years since they announced it, and they don't even have all of the permits yet. I question the efficiency of land use as well -- 9400 acres for 200MW, compared to 4500 acres for 500MW for the Victor Valley project I mentioned above and between 2500 and 1600 acres for 1000MW for the setup in TFA. They claim a construction cost of less than US$200M, but I would not be at all surprised if they miss their mark significantly.
        • by greg_barton (5551) * <greg_barton@ya[ ].com ['hoo' in gap]> on Friday November 10, 2006 @04:57PM (#16798514) Homepage Journal
          The solar electricity is simply profitable.

          Not without tax breaks, it's not

          That's cool.

          So, maybe now that we have a Democratic congress, we can shift those gargantuan tax breaks the oil and gas industries got over to the solar industry?

          They claim a construction cost of less than US$200M, but I would not be at all surprised if they miss their mark significantly.

          Don't we spend about that much per day in Iraq? I think we can spare a bit to remove our reason for being there.
          • Re: (Score:3, Informative)

            by Martin Blank (154261)
            Despite the massive sizes of the profits, keep in mind that the $10B quarterly numbers come on gross revenues of more than $100B, with income taxes alone totaling several billion dollars. The profits are 10% or less, and if you look at the history of the companies, you'll see that they jump around a lot, going into loss every so often. No one expected $10 oil prices in the 1990s, and it's quite possible that the oil companies will get bitten again as they go looking ever deeper for new oil deposits.

            There
      • by Smidge204 (605297) on Friday November 10, 2006 @01:26PM (#16795520) Journal
        Just to point out: Those units in California are not photovoltaic. Those are solar-thermal Stirling generators.

        Just a nitpick, really. I'm also quite excited about that project.
        =Smidge=
      • by kfg (145172) on Friday November 10, 2006 @01:47PM (#16795828)
        what's even more remarkable is that there is no federal or state funding for this project

        The R&D was federally financed. I've done some work on it myself.

        One of the advantages of this technology is that it is not solar. It's thermal. An external "combustion" engine is used to drive the generating turbine, thus any source of heat may be used.

        One of the problems with solar power is that it is unreliable; innately. Some sort of storage/backuup system must be available to go online at all times. By using a heat engine to turn a generator instead of direct conversion to electricity, when the sun goes down you can just throw some buffalo chips (or whatever) in the firebox. There's no need for a completely redundant infrastructure.

        KFG
        • Re: (Score:3, Funny)

          by Dunbal (464142)
          One of the problems with solar power is that it is unreliable; innately.

                Solar power is reliable as hell. What's not reliable is our atmosphere!

                Dyson spheres, anyone?
          • by kfg (145172) on Friday November 10, 2006 @02:09PM (#16796146)
            Solar power is reliable as hell.

            Dude, the whole impetus for developing an electric power infrastructure in the first place was the desire for lighting when it's dark out.

            KFG
            • Re: (Score:3, Insightful)

              by Dunbal (464142)
              the desire for lighting when it's dark out.

                    Yeah but now that we have clocks and almanacs and things, we know exactly WHEN it will be dark out. The sun rises every day. That's pretty reliable. Not the sun's fault this hulk of a planet gets in the way for half the day.
        • by llefler (184847)
          One of the advantages of this technology is that it is not solar. It's thermal.

          Depends on how narrowly you define solar. It's not photovoltaic.

          And if you used it as a peaking station it wouldn't matter whether it generated after dark. Peaking stations are primarily used during the hot summer days when everyone cranks their air conditioning to 11. The rest of the year, since generating stations are part of a system, it would allow the coal and gas plants to work at lower levels or be taken off line for maint
      • by sane? (179855)
        Just to point up this recently announced project [solarsystems.com.au] in Australia, using on Solar PV concentrators. 154MW and $500m makes it a sizeable programme with plans to extend even further.
  • Obvious to me... (Score:5, Interesting)

    by Fishbulb (32296) on Friday November 10, 2006 @12:50PM (#16794946)
    Why all the talk of centralized power generation?

    Solar panels are the way to put power generation into the hands of the people. When I look out at all the rooftops in the area - houses, office buildings, Super S-Marts and their enormous un-covered parking lots, all I can think of is if every one of those surfaces had a single solar panel our energy demands from centralized (corporate :p) energy would a fraction of what it is now.

    Have we learned nothing from decentralized computing?

    • Durability (Score:4, Interesting)

      by Chas (5144) on Friday November 10, 2006 @01:19PM (#16795372) Homepage Journal
      Part of the problem is the durability of these panels. The affordable ones have relatively short lifespans (under 10 years, and at that point, still haven't saved enough to justify their cost). The ones that ARE durable enough to last longer are hideously expensive, and not the sort of thing most people have the cash for.

      Also, there's the fact that solar power is not a viable solution everywhere in the world. Sure, in Arizona, California, etc, it is a wonderful "free energy" thing.

      In Pacific Northwest, the northern Midwest, etc, especially during the winter months, solar power is a complete non-option.
      • by bhima (46039)
        Care to source a study that's not from the early '80s for "The affordable ones have relatively short lifespans (under 10 years, and at that point, still haven't saved enough to justify their cost)"?

    • Re: (Score:2, Interesting)

      by lagunathed (1025578)
      I ran across some technology where a building can use its windows (with a clear / tinted film) to capture sunlight to generate power. It's not bleeding-edge new, but we may see some advancement fairly soon. Imagine self-sufficient office buildings or houses for that matter. XsunX [xsunx.com] is one of the businesses I have been following.
  • by majutsu (1018766) on Friday November 10, 2006 @12:50PM (#16794954)
    years. One of the major problems of concentrated solar power is the heat - normal photovoltaics would melt. The benefit is that concentrated light also has better efficiency than the normal ~10-22% of normal solar power. One of the traditional ways around the heat problem wasn't to use a photovoltacic as all. An energy farm in Australia uses dishes to focus the light and at the focal point places a stirling engine, with only the heat powering it. Interesting stuff. I hope to have my own workable solar power system power my property one of these days.
  • by Nom du Keyboard (633989) on Friday November 10, 2006 @12:51PM (#16794974)
    using traditional photovoltaics requires a four-square-mile area of silicon...A concentrator system, he says, would replace most of the silicon with plastic or glass lenses or metal reflectors, requiring only as much semiconductor material as it would take to cover an area the size of a typical backyard.

    Let's see, four square miles of sunlight focused onto my back yard. Conversion efficiency ~30%. Melting point of silicon 1414 deg C.

    Unless I've got a backyard the size of Bill Gates, lifetime of new solar plant = one sunrise.

  • "Indeed, if manufacturers can meet the challenges of ramping up production and selling, distributing, and installing the systems, their prices could easily meet prices for electricity from the grid, says solar-industry analyst Michael Rogol, managing director of Photon Consulting, in Aachen, Germany."

    I've heard that Photon Consulting is really fast.

  • by Doc Ruby (173196) on Friday November 10, 2006 @01:03PM (#16795170) Homepage Journal
    Americans vote Democrats control of our government, and suddenly 3 days later solar power could be affordable. When they actually take power on 1/3/2007, will we finally get our goddamn flying cars?
  • by b0s0z0ku (752509) on Friday November 10, 2006 @01:04PM (#16795180)
    A lot of oil and other fossil fuel is expended heating homes. With proper design - like areas of south-facing insulated glass combined with materials that store and release heat (thermal mass) you can have a house that's at least partially self-heating in winter. This doesn't require expensive photovoltaic panels or thermal solar systems. This just requires a bit of thought when building or renovating a house. You can even use build the solar area of the house as a small greenhouse and use it to grow vegetables (far healthier than eating chemically-polluted stuff from the grocery IMHO) almost year round.

    What about in summer? The windows can be opened and replaced by screens or shaded.

    -b.

    • by budgenator (254554) on Friday November 10, 2006 @01:28PM (#16795550) Journal
      You'd be amazed what can be done without proper design. Last year after the natural gas price spike, my wife went on a nut and turned the heat down to 55 for the winter. I'll admit it was a bit chilly at times and sweaters or sweatshirts became our casual dress around the house but by just opening and closing drape at the opportune times, we could keep the house above 65 during the day, above 62 during the evenings. We found it was more comfortable to shower with the bathroom door closed.
      • by b0s0z0ku (752509)
        I'll admit it was a bit chilly at times and sweaters or sweatshirts became our casual dress around the house but by just opening and closing drape at the opportune times, we could keep the house above 65 during the day, above 62 during the evenings. We found it was more comfortable to shower with the bathroom door closed.

        Hah, maybe your house was *already* properly designed, by coincidence, luck or whatever. Now here's an interesting idea - a few electric eyes, temperature sensors and motor actuators for

      • Re: (Score:3, Insightful)

        by dave1g (680091)
        Being a frugal college student I hate to run the horrible electric heater that my apartment comes with. So what do I do? I take showers with the ceiling fan on to draw out the steam( heat+humidty feel very good in the dry/cold winter months in Austin Texas...yes i know it doesn tget extremely cold cut we still get below comfortable.) I also shower with the drain plug closed. I dont drain the bathtub until either the next shower or until I have noticed the water has returned to room temp. Thus assuring me th
    • Re: (Score:2, Funny)

      by great90wt (985599)
      I heat my house with solar power already. I use natures solar power storage system, wood. The trees are nice enough to store it for me in a solid form until I need to release it again.
      • by b0s0z0ku (752509)
        I use natures solar power storage system, wood. The trees are nice enough to store it for me in a solid form until I need to release it again.

        Actually, biomass is a decent idea. The trick is to make sure that you're not burning whatever you're burning faster than it can regrow. Also, burning it in a stove is preferable to a simple fireplace since you can control combustion better and have more efficient burning with less pollutants going into the air. There are also some other issues to consider like d

    • Have you ever priced automatic drapes? Not some $70 break-in-a-year crap from x-10, but something to actually count on for partof your heat? They start at about $500/window (google for Somfy). Even in my old 1962 clunker of a house, with poor siting and uninsulated first floor (CMU, partially below grade), I spend about $750 to heat and cool the house in a year. Just equiping the "primary" solar gain windows in my house would run about $4000 for the parts alone (yes, I've looked).

      I'm all for green building
      • by b0s0z0ku (752509)
        Have you ever priced automatic drapes? Not some $70 break-in-a-year crap from x-10, but something to actually count on for partof your heat? They start at about $500/window

        Only because there's no economy of scale present currently. If demand goes up, price will go way down. And my initial post didn't discuss using automatic drapes, just designing to gather solar energy passively. It's possible without things like auto. drapes.

        Of course, one thing often overlooked is incandescent lighting.

        I don't d

    • by Lumpy (12016) on Friday November 10, 2006 @02:30PM (#16796438) Homepage
      First building a proper and efficient home is extremely hard to do.

      1 - they are "ugly" to most people that want the cookie cutter that looks like the other 15 homes in the new subdivision.
      2 - They require more land than the typical suburbian/urban lot offers.
      3 - Actually paying for low-e glass + correct design + insulation is expensive! They would rather have cherry cabinets, stone fireplaces with a plasma TV above it than energy efficiency.
      4 - building from real materials is also insane expensive. I live in a all brick and Stone home now that is from the 1950's It's beautiful and would cost nearly $1,000,000 to build today. The stonework is real the brickwork is real my walls are 2X6 and then have the stonework on the outside giving me 10-12 inch thick walls, new mansions dont have real stone anymore, they have the faux or created stuff that is in reality only an inch or two thick even for their fireplace stonework (I have real marble and limestone) so building the home to have real thermal capabilities is not possible except for the rich.

      5 - efficient materials like adobe is illegal most places, an adobe home is incredibly efficient.
      6 - efficient designs are hard to get approved by the association... Any home that looks different is considered ugly. Domes are the absolutely most efficient. I had one that during some winters was self heating due to the sliders and skylights to the south. Paying $85.00 a year for propane for heat is really stinking nice(1999-2002)

      The common person cant have an efficient home, they cant afford it. Jsut like solar and alternative energy. No average joe can float $5000-8000 for a basic solar install that will pay back in 10 years saving few dollars here and there.
      • Re: (Score:3, Interesting)

        by b0s0z0ku (752509)
        1 - they are "ugly" to most people that want the cookie cutter that looks like the other 15 homes in the new subdivision.

        Not necessarily. Besides, the suburban houses that are being barfed up by builders there days are cheaply built and ugly. Yay for particleboard (not the good kind!) roof beams. How they get some of that stuff past the inspectors I can only guess.

        2 - They require more land than the typical suburbian/urban lot offers.

        Incorrect. We had a 1200 sq ft beach house on a *tiny* (read

  • I understand the attraction to a direct-to electricity approach has such as low to no maintenance; but it just seems to me that other approaches such as solar boilers and sterling generators are going to have an edge for quite some while. The ability to throw some more sunlight at the target can overcome many mechanical inefficiencies, I think this is like computer upgrades, sometimes you just have to go for it because there will never be an optimal time
  • Energy Innovations (Score:2, Informative)

    by Ankur Dave (929048)
    Is this at all related to what Energy Innovations [energyinnovations.com] has been doing?
  • Nitpick (Score:5, Insightful)

    by Rob T Firefly (844560) on Friday November 10, 2006 @01:08PM (#16795244) Homepage Journal
    Solar Power Becoming More Affordable
    Solar power has always been free. It's the gadgetry that can convert it to certain other kinds of power for us that are getting more affordable. </pedanticbastard>
  • thermovoltaics (Score:3, Interesting)

    by spankey51 (804888) on Friday November 10, 2006 @01:14PM (#16795308)
    One thing I really wish would happen is that the efficiency of thermovoltaic technology could somehow be improved... Think about how much energy is wasted as heat; eventually all of it, I suppose. I actually heat my bedroom in the winter with my PC. When I read about large scale solar facilities, I can't help but wonder at the losses in heat that are going on there. There are more efficient ways of utilizing solar power right now anyway: http://www.stirlingenergy.com/ [stirlingenergy.com] comes to mind... and they work pretty well. It would be nice, however, to move the technology to solid state like we have with photovoltaic cells; That way we could apply them to things like brake shoes on cars, the condensers on refrigerators and air conditioners, etc... -Photovoltaic paint has been invented, but is not realistic yet. I think that's where the future is: Objects that need electricity should become more efficient, and should have photo/thermovoltaic technology built right into them.
    • Re: (Score:3, Insightful)

      by b0s0z0ku (752509)
      That way we could apply them to things like brake shoes on cars, the condensers on refrigerators and air conditioners, etc...

      Your idea about the computers and brake shoes would work -- in theory. However, with car and train braking, there's a better way to extract energy from braking - just use an electric motor running as a generator to slow the car. It's done in hybrid cars and the NYC subway.

      As far as the condensers in fridges and A/C units, it won't work, since you'll need more energy to run the t

  • Just think ... to save even more space, we can use several layers of reflectors ... oh, wait ....
  • by gurps_npc (621217) on Friday November 10, 2006 @01:26PM (#16795518) Homepage
    30 years ago, we did not have the technology to create cheap solar panels. They were very expensive. The need for pure silicon in the computer industry forced us to develop cheap methods of manufacturing pure silicon, which is perfect for solar panels.

    But the demand for silicon in the creation of computers, has kept the price high. It is an ironic, catch 22 situation.

    But there is hope. If we ever switch to non-silicon based computers, the price of pure silicon is expected to drop to a level low enough to make cheap solar panels a reality.

  • One small hair in the ointment. $$$,$$$,$$$,$$$

    Figure out the cost of a solar reflector, both for fixed position and steerable ones. One strong enough to survive wind and rain.

    Then figure out the cost of maintenance.

    Then figure out how to convert this focused sunlight into electricity. Hint: photovoltaic cells won't do it.

    Then figure out how much you'll have to pay in interest every yearto borrow that amount of money.

    Compare with the wholesale value of thwe generated electricity.

    You're likely

  • by necro81 (917438) on Friday November 10, 2006 @01:42PM (#16795754) Journal
    I've worked a lot with photovoltaics. They're really cool, but I recognize their limitations for utility-scale power generation. The primary limitation is that silicon-based photovoltaics currently convert only 10-23% or so of the incident solar power into useful electricity. Silicon solar cells cannot convert infrared light to electricity - the photons have too little energy. Higher energy photons (visible and UV light) are poorly utilized - a solar cell will get the same energy output from a red photon as a blue one, despite the fact that the blue photon has higher energy. Solar cells aren't very reflective (by design), so most of the remainder of the unconverted sunlight becomes heat in the cell.

    You can get higher efficiencies by going to other chemistries, like GaAs, and by layering different chemistries on top of one another. These are not cost effective, and won't ever be able to get above, say, 50% efficiency.

    But solar energy is not limited solely to photovoltaics. Probably the best way to use solar energy is solar thermal - capture all that 1000 W/m^2 of incident sunlight as heat. It can be used to heat a fluid up to fantastic temperatures, which can drive turbines, etc. This is the principle behind Solar One, Two, and Tres [wikipedia.org] and the Nevada Solar One [wikipedia.org] plants. These are, however, demonstration plants, not utility scale.

    The other major kind of solar energy is biomass. Photosynthesis is a pretty good way to capture sunlight and make it do something useful. Plants have had a looong time to get good at making use of sunlight, which we use to our benefit in many ways. When cellulosic ethanol comes around, you'll probably make better use of sunlight by planting crops and building a solar power station.
    • by MZdoctor (634109)
      You forget the five Solar Thermal plants at Kramer Junction which together produce 165 MW. SEGS III - VII, as they are called, have been in commercial operation for around twenty years now. These are definitely utility scale plants, not demonstration plants.
  • by Skapare (16644) on Friday November 10, 2006 @01:51PM (#16795890) Homepage

    We still need better inverters. These are the devices that convert DC into AC for use by common appliances and to power your home. The ones designed for home operation are wimpy, apparently intended for a home where people trim back on using energy in electrical form, already. The ones designed specifically for the wide range of voltage change from photovoltaic arrays/strings are big expensive commercial units intended for selling power to utilities, or for the utilities to buy for themselves (they shut down and night and can't run from batteries very well).

    I want to reduce my carbon footprint with emphasis on reducing use of fossil fuels in particular. I'm less concerned about burning wood than I am about burning gas (natural gas or liquified propane). So I'd like to run my kitchen from solar and wind generated electricity. That means I need on the order of 12 kW of power just for potential peak cooking. Add another 2 kW for microwave. Add some more watts for the blender, coffee maker, refrigerator, etc. It adds up.

    One of the big makers of home inverters for general DC conversion (e.g. batteries charged from various sources) is Xantrex. But their largest unit in this market segment is only 5500 watts. Two of the North American 120 volt units can be "stacked" to get 120/240 volts, but that's still only 11 kW. Some other companies offer as much as 6000 watts in a single unit, and do not even appear to be "stackable". What we need is a line of inverters, each specifically designed for the various world power systems so people can use their common domestic appliances, but with a variety of power levels in many steps all the way up to 100 kW or more.

    There is one technical issue with inverters, and this is not something that is easy to solve. It also exists to some extent with small generators. That issue is that under short circuit conditions, they produce only barely (about 15%) more current than their design rating. To many this might seem like a good thing. But it actually is a hazard. The reason is because short circuits will fail to trip home branch circuit breakers. A common circuit breaker rated for say 15 amps generally won't trip for a while under a 20 amp load, until its thermal element gets quite warm. For an instantaneous trip using its magnetic element, the current has to be significantly higher, like 150 amps or more. Utility power through a transformer can easily deliver several hundred amps under a short circuit condition. With hefty power lines and transformers these days, if you are close to the transformer, you could even get several thousand amps real close to the breaker panel. This is why if you have ever shorted out a power circuit, you get a nasty *POP*. That's some big amps followed by the breaker cutting the circuit off.

    I've found some inverters that have circuit breakers on the output AC side that are rated at a higher amperage than the maximum they could deliver under a short circuit condition. In other words, short out the AC right after the circuit breaker and you can't even get enough juice to cause the breaker to kick off. The inverter itself may very well detect the overload and soon shut off.

    Many appliances may not even work under this low fault current condition. Big motors can have trouble getting started if they can't pull 3 to 5 times the normal amperage for part or all of a second. And even some electronics wants that much power or more when you turn them on to charge up the power supply capacitors. One relative has found that his big screen TV, although using way less than the 5000 watts his generator can produce, just won't even turn on under the generator. When he turns it on with utility power, all the lights in the house dim significantly for just an instant as the monster sucks a huge number of amps.

    Ultimately, if you want to power you whole home with AC power through an inverter that converts the DC stored in your batteries charged up from your solar and/or wind power sources, you'll need some hefty

  • There was a good Wired Article [wired.com] on a startup company developing a solar cell product using a concentrator back in June of 2005, which included good coverage of the reasons behind using concentrators, as they're much cheaper than silicon, and solar cells can handle much more intense light than plain sunlight.
  • Hallelujah! (Score:3, Funny)

    by jpellino (202698) on Friday November 10, 2006 @01:52PM (#16795912)
    Finally - this can only mean that Halliburton and Bechtel decided to lower the price of photons!

  • Cheaper Mirrors? (Score:2, Insightful)

    by Reidsb (944156)
    There has to be a HUGE stockpile of old AOL CDs still out there, lets put them to good use.
  • by Skapare (16644) on Friday November 10, 2006 @02:15PM (#16796252) Homepage

    These concentrating lenses do not need to be very complex at all. In fact they don't even need spherical curvature at all. What they need are angles. That effectively makes a crude, but adequate, Fresnel lens. With flat surfaces, they are also cheaper to make.

    The original Fresnel lens design for lighthouses needed to work with a very small focal point, the light source, and beam that light very straight. Thus it needed that spherical curvature. Even in its varies steps or layers, that sperical curvature still exists. Solar cells, however, do not need this.

    Suppose you have a small solar cell module that measures 10cm x 10cm. Place it at the center of the back of a larger 50cm x 50cm box with the front aimed directly at the sun. Over the front of the box place a 5x5 grid of 25 openings, each the size of the solar cell. In the center, only a flat piece of plastic is needed. Outward from the center, a piece of plastic that is angled like a thin prism would be placed to bend the light at the necessary angle to hit the solar cell at the back. You'll have to figure out the right angle based on how deep the box is. But you will only need to have just a few different kinds of angles to complete the construction and concentrate almost 25 times the light onto the solar cell. Solar cells even operate more efficiently on concentrated light levels.

    The box will need to track the sun to keep the various angled beams focused on the solar cell.

    An alternative design is a box that is wider in one dimension and has open sides in the other. Stack multiple boxes with the wider dimension vertical so their open sides mate with each other. Tilt the stack to the angle of the sun's path and aim it for about the noon sun position. Then the morning and afternoon sun will be at an angle that lens light from one of these narrow boxes go through the mated openings and hit the solar cells of the adjacent box. You only lose what would be at the ends but you don't have to set up a steering mechanism.

    Variations of these designs use mirrors instead of lenses to concentrate light. I personally favor the mirror designs using non-imaging reflective topologies. The same methods are also used for water heating.

    Also consider using a water heat collector behind the solar cells. They do get hot (they aren't 100% efficient, so the energy is wasted somewhere).

  • Wow, that's just 3.025 square miles to generate 1.21 gigawatts.


  •     From my recollection, cells that are used with concentrators tend to brown, deteriorate, and lose production capacity much faster than those that aren't. That hasn't changed, has it?

    steve
  • Does this mean they've finally found a use for Nevada?
  • by Shannon Love (705240) on Friday November 10, 2006 @03:55PM (#16797704) Homepage
    The problem with solar power is never the efficiency of the collection system but rather with the fact that the power cannot used on demand. Without a staggeringly efficient means of storing the power, solar power will remain useless for all serious generation. There isn't a single factory, communication system, transportation system or any other important part of our civilization that runs off solar power and baring currently unforeseen breakthroughs in storage technology there never will be. We simply can't run a modern civilization off a power source that randomly disappears. Every solar power installation requires a 100% non-solar redundant system to take up the slack when the solar goes off line. Factor that cost in and solar power becomes an economic joke.

    Solar power isn't a solution. Its a distraction. It lets politicians and others pretend that they are doing something about serious energy questions instead of making unpopular, real-world choices.
    • Re: (Score:3, Informative)

      by MichaelSmith (789609)

      Every solar power installation requires a 100% non-solar redundant system to take up the slack when the solar goes off line. Factor that cost in and solar power becomes an economic joke.

      Power grids supply a mixture of peak and base load. During the day in the summer here in Australia a lot of the peak load goes to supply commercial aircon systems which do scale the same way as solar power systems.

      You may need to bring your peak load generators (gas powered, usually) on at night but there is still a net ga

    • Re: (Score:3, Informative)

      I'm still not clear about how solar power stacks up as a primary power generation system. But it's not nearly as dire as you're claiming.

      The first thing to remember is that people usually go down when the sun does (give or take). During the day, when solar power is producing the most, people are up and running, working in their power hungry manufacturing plants and cubicle farms. That's when we need the most energy, so when it comes time to decide whether to build a new coal-fired plant, and it's only ne
    • by James McP (3700) on Friday November 10, 2006 @06:14PM (#16799434)
      What a horribly foolish and short sighted statement. While it is true that solar works when the sun shines, it also works when it is cloudy, albeit producing less power. Therefore the average annual power production of solar is dependable on an annual basis.

      Power storage for solar can come in many forms. For a solar-thermal system (i.e. a stirling engine generator) you can simply store the heat using one of many mediums. For a photovoltaic system you can store the power using batteries, capacitors, hydrogen, heat, or even gravity by pumping water uphill. While the last three require a hybrid power system to access the stored energy (PV->H2/heat/gravity->electricity) they are not new technologies. In most areas you won't want a single power generation system so you'd have multiple plants anyway. The solar-thermal systems are particularly compatible with stored power as they work under direct solar energy, stored heat, or any combustible fuel (coal, wood, ethanol, petroleum, etc). And a solar/hydrogen power plant would double as a power source for hydrogen vehicles.

      While it is true that areas closer to the equator see more power generation capacity from solar, even areas farther away still benefit from solar's ability to mitigate peak demand in summer and winter.

      The cost of solar (PV or thermal) eliminates the almost incalculable secondary costs of conventional fuels (impacts on asthmatics from particulates, acid rain, ecological damage from mining coal or spilling oil, etc).
      • Re: (Score:3, Insightful)

        by trawg (308495)

        While it is true that areas closer to the equator see more power generation capacity from solar, even areas farther away still benefit from solar's ability to mitigate peak demand in summer and winter.

        I think this is one of the biggest things about solar power that is sadly most often overlooked. Sure, it'd be hell nice to drop all our coal burning plants and replace them with PV panels or thermal Stirling engines or whatever - but noone really expects that to happen overnight.

        But dropping a few panels on

    • Re: (Score:3, Insightful)

      by NerveGas (168686)
      That doesn't mean that it's useless. More electricity is used during the day, when solar works best.

      Even if we kept the fossil-generators for surge and nighttime, if we managed to produce 35% of our electricity through solar, we'd have cut down our pollution rate considerably. Potentially even more than 35%, because generating 1 kilowatt at a home means that the power plant 20 miles away (or more) can reduce production my significantly more than 1 kilowatt.

      Even with the grid-tie, it isn't an economic joke
    • Re: (Score:3, Informative)

      by evilviper (135110)

      Without a staggeringly efficient means of storing the power, solar power will remain useless for all serious generation.

      That's utter nonsense.

      First off, solar doesn't NEED to be stored. You can use it when it's being generated, and replace along the lines of 50% of fossil fuel power plants. Hydro electric handles 30% of all power needs in California, so here that would leave just 20% to be powered by wind, tidal, nuclear, or existing fossil fuels (coal/natural gas).

      And besides that, there are numerous, hi

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