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Vast New Energy Source Almost Here

  1. Sep 9, 2004 #1
    "Vast New Energy Source Almost Here"

    http://www.sciencedaily.com/releases/2004/08/040825094820.htm

    What do you think? I am naturally skeptical, but with such strong claims being reported in many credible sources, I also think and hope that something huge may come of it.

    Given the low electric output of photovoltaics (compared to fossil fuels and such), it's hard to believe that this can be as viable as they say, but the cheapness of the materials appears to be the savior.

    I'm conflicted and optimistic.
     
  2. jcsd
  3. Sep 9, 2004 #2

    Ivan Seeking

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    Also, please see this thread for much more information about Hydrogen.

    https://www.physicsforums.com/showthread.php?t=29373

    For some specific information related to this post.

    Multi-step metal oxide cycles for solar-thermal water splitting
    http://www.colorado.edu/che/TeamWeimer/perkins.htm

    Project : Solar Hydrogen by a 2-step H2O-splitting thermochemical cycle
    http://www.pre.ethz.ch/cgi-bin/main.pl?research?project6

    Solar thermal ZnO-decomposition
    http://solar.web.psi.ch/daten/projekt/zno/roca/roca.html

    Also:
    http://216.239.39.104/search?q=cach...solar+furnace"+efficiency+cost+problems&hl=en

    or

    http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/iie2_raissi.pdf

    Most of these address ZnO, but I remember seeing titanium mentioned somewhere in all of this as well.
     
  4. Sep 9, 2004 #3

    chroot

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    It still doesn't solve the problem that the solar flux at noon is about a kilowatt per square meter, which isn't enough to really be a solution to mankind's energy needs even if the devices can be made to be nearly 100% efficient. Even if you harvest all the energy there is to harvest from sunlight, it's still not enough for man.

    - Warren
     
  5. Sep 9, 2004 #4
    Are you sure about that?

    http://www.nmsea.org/Curriculum/7_12/The_Solar_Resource.htm
     
  6. Sep 9, 2004 #5

    Ivan Seeking

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    The basic strategy is to utilize the most effective means of production for any area. If these catalyzed reactors can produce cost competitive H2, they become part of a spectrum of solutions for H2 production. Here are some examples of production methods quoted from the other thread.

    Direct production from whole biomass
    Gasification
    Thermal/Steam/Partial Oxidation

    A technical note by Williams (1980) (USA) makes a case for efficient hydrogen production from coal using centrifuge separation of hydrogen from other gases following steam gasification at 1100-5000°C. Recent advances in new materials developed by the aerospace industry made it appear possible to develop such a gaseous centrifuge.

    A large number of single research studies have appeared from 1981-2000, from researchers in many countries around the world. Brief notes follow. McDonald et al. (1981) (New Zealand) proposed extracting protein from grass and lucern and using the residue for hydrogen production (among other fuels). Saha et al. (1982, 1984) (India) reported using a laboratory-scale fluidized-bed autothermal gasifier to gasify carbonaceous materials in steam. Further studies with agricultural wastes were planned. Cocco and Costantinides (1998) (Italy) describe the pyrolysis-gasification of biomass to hydrogen. More-or-less conventional gasification of biomass and wastes has been employed with the goal of maximizing hydrogen production. Researchers at the Energy and Environmental Research Center at Grand Forks have studied biomass and coal catalytic gasification for hydrogen and methane (Hauserman & Timpe, 1992, and Hauserman...

    Hydrogen from Biomass-Derived Pyrolysis Oils Laboratory work using this approach has been conducted at NREL (USA), starting in 1993 (see Chornet et al., 1994; Wang et al., 1994; Wang et al., 1995; Chornet et al., 1995; and Chornet et al., 1996 a, b, c). Early papers present the concept of fast pyrolysis for converting biomass and wastes to oxygenated oils. These oils are subsequently cracked and steam-reformed to yield hydrogen and CO as final products (Mann et al., 1994). The 1995 Wang report presents the chemical and thermodynamic basis of this approach, the catalysis related to steam reforming of the oxygenates, and the techoeconomic integration of the process...

    Six progress reports in 1996 and 1997 document the systematic exploration of the pyrolysis oilto-hydrogen process. In Chornet et al. (1996a) bench-scale experiments determined the performance of nickel-catalysts in steam reforming of acetic acid, hydroxyacetaldehyde, furfural, and syringol. All proceeded rapidly. Time-on-stream experiments were started. In Chornet et al., (1996b), Czernik et al., (1996), and Wang et al. (1997a), the approach of using extractable, valuable co-products with the balance of the oil converted to hydrogen is explored.
    ---------------------------------

    Small scale reformer technologies
    -------------------------------------

    Four types of solar photochemical hydrogen systems have been identified: photochemical systems, semiconductor systems, photobiological systems and hybrid and other systems. Asurvey of the state-of-the-art of these four types has been presented. The four system types (and their sub-types) have been examined in a technological assessment, where each has been examined as to efficiency, potential for improvement and long-term functionality. Four solar hydrogen systems have been selected as showing sufficient promise for further research and development:

    1. Photovoltaic cells plus an electrolyzer
    2. Photoelectrochemical cells with one or more semiconductor
    electrodes
    3. Photobiological systems
    4. Photodegradation systems
    ------------------------------------

    Photoelectrolytic and Photobiological Production of Hydrogen
    -----------------------------------------------------

    Hydrogen by Catalytic Decomposition of Water:
    Researchers at DOE’s National Energy Technology Laboratory and Argonne National Laboratory have patented a "Method of Generating Hydrogen by Catalytic Decomposition of Water." The invention potentially leapfrogs current capital and energy intensive processes that produce hydrogen from fossil fuels or through the electrolysis of water. According to co-inventor Arun Bose, "Hydrogen can be produced by electrolysis, but the high voltage requirements are a commercial barrier. The invention provides a new route for producing hydrogen from water by using mixed proton-electron conducting membranes." Water is decomposed on the feed surface. The hydrogen is ionized and protons and electrons travel concurrently through the membrane. On the permeate side, they combine into hydrogen molecules.
    --------------------------------------------------------

    DENSE CERAMIC MEMBRANES FOR HYDROGEN SEPARATION
    ------------------------------------------------------

    HYDROGEN FROM COAL

    See also:
    A NATIONAL VISION OF
    AMERICA'S TRANSITION TO
    A HYDROGEN ECONOMY —
    TO 2030 AND BEYOND
    February 2002
    Based on the results of the
    National Hydrogen Vision Meeting
    Washington, DC
    November 15-16, 2001

    http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/vision_doc.pdf
     
  7. Sep 9, 2004 #6

    Gokul43201

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    This is interesting as well as very confusing. I too was under the impression that the energy density from incoming solar radiation was too low to sustain us - not sure where I got that idea from.
     
  8. Sep 9, 2004 #7
    The problem is not on the energy-harvesting side of things. The problem is on the use side of things. We (people in technologically advanced nations) are generally very wasteful. Our governments could easily end this if they really wanted to do a bit of that saving the Earth stuff.
     
  9. Sep 9, 2004 #8

    russ_watters

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    Warren said 1kW/m^2 at noon - your link said 1kW/M^2 for 8 hours: I don't think they take into account the change in angle of the sun. That's fine if your collectors move to follow the sun, but then they'd need to be spaced far enough apart that they don't shadow each other.

    30% efficiency is also pretty generous.

    Given these generous estimates, the calculated 300x100 km^2 is pretty conservative - by maybe as much as a factor of 5.

    But even accepting their calculations, how much would 30,000 sq km of solar cells and the associated distribution systems, controls, and maintenance cost and how long would it take to build? I'm not saying we shouldn't look into it (we should), but it would be quite a feat of engineering and economics to build such an array.

    Also from the link:
    This varies greatly by the home of course, but I do support tax incentives to put solar panels on homes. They aren't cost effective on their own.
    When it comes to electricity, we're not as wasteful as most people think. People think in terms of incandescent vs fluorescent lighting in homes (the difference is huge: 70%+), but most energy usage isn't in homes, its in businesses. With the enormous amount of money energy usage costs a business, there isn't all that much they can do that they aren't already doing (have you ever seen a business that used incandescent lighting?).
     
    Last edited: Sep 9, 2004
  10. Sep 9, 2004 #9

    Gokul43201

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    I think most of the energy consumption is by heavy industry, and they sure as hell try not to be wasteful. So I second russ on this.

    At the same time, sowing the idea of energy responsibility is important and should be done independently of allowing it to be a natural consequence of a capitalist rationale.
     
  11. Sep 9, 2004 #10

    Ivan Seeking

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  12. Sep 9, 2004 #11

    Ivan Seeking

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    http://www.eia.doe.gov/emeu/cabs/usa.html#elec
     
  13. Sep 9, 2004 #12

    russ_watters

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    Caveat: that's all types of energy, not just electrical. AFAIK, electricity is by and large commercial while the non-electric hydrocarbons lean more toward personal use (cars and houses). I wish that site had broken the info down differently, but there is an enormous amount of info available if I take the time to look for it...

    I emphasize electricity for two reasons: One, solar cells (the specific topic of this thread) are only usable right now for producing electricity - hydrogen production is a secondary application. Two, electricity is where I see the biggest problem due to our dependence on coal. Coal (according to that first site) accounts for a full quarter of our energy usage - virtually all of that being in the form of electricity. That, IMO, is the first change that needs to be made.
     
  14. Sep 9, 2004 #13

    Ivan Seeking

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    I didn't spot the desired desired statistics on the first try but the link was so good that it seemed a shame to waste it.

    Russ, note that this produces H2 gas, not electricity. It' is solar so those limits apply, but we still need to convert to electrical for this supply.
     
  15. Sep 9, 2004 #14

    Ivan Seeking

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    Strange; this surprises me quite a bit. I expected the industrial sector to use relatively more electrical energy.

    According to page 5 of 11 of the first link,
    http://www.agmrc.org/markets/info/energyoverview.pdf

    the commercial and residential sectors each use about 4 quadrillion BTUs of electrical energy, with losses of about 10 QBTUs. Industry uses about 5 QBTUs, with losses of about 8 QBTUs.
     
    Last edited: Sep 9, 2004
  16. Sep 9, 2004 #15
    Your statements are well-founded, but I was not trying to propose creating the scenario in the link, only trying to address Warren's statement:

    He was saying that even if we had 100% efficiency, we could never harvest enough sunlight for man's use. I think that there is well more than enough energy for forseable needs in the form of solar radiation. Just think about it. Solar radiation invariably provided us with all our energy with the exception of nuclear (although some, such as oil, has accumluated over much more time than we have used it for). Just think about the fact that solar radiation alone keeps the Earth as warm as it is.

    The questions are "How much of that can we harvest?" and "How much would it cost?".
     
  17. Sep 10, 2004 #16

    Ivan Seeking

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    Dan, are you more optimistic now? :biggrin:
     
  18. Sep 10, 2004 #17

    russ_watters

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    Yeah, I'm actually not quite sure what some of those graphs are trying to say. I don't understand what they mean by "losses." If that's just efficiency loss, I'm not sure why they break that out. But it looks like from the "Industrial" graph on page 5 that they still use a lot of oil and natural gas for industrial processes - it could also be that a lot is used for on-site power generation.

    Also, the 2 graphs on page 2 seem to contradict each other. The graphs aren't labeled well and aren't cited specifically in the text (jeez, who wrote that thing?). I'm going to see if I can find better (more coherent) info.
    Yes, I know - I was just saying what I am more concerned with.

    Also, I've started a related thread: YOU!: Fix the US Energy Crisis
     
    Last edited: Sep 10, 2004
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