the Air Vent

Because the world needs another opinion

Solar Power Stepping Forward

Posted by Jeff Id on August 3, 2010

I’m certain that solar power will be a functional replacement for home energy in the future.  It’s not now, but soon it will be.  We just need big generation and storage breakthroughs and we can chuck the coal out the window.  The reality is that unlike biofuel lies, solar is a real future solution.  We just need to wait a decade or two and we’ll be there.  Check out the link.


New Solar Energy Conversion Process Could Double Solar Efficiency of Solar Cells

ScienceDaily (Aug. 2, 2010) — A new process that simultaneously combines the light and heat of solar radiation to generate electricity could offer more than double the efficiency of existing solar cell technology, say the Stanford engineers who discovered it and proved that it works. The process, called “photon enhanced thermionic emission,” or PETE, could reduce the costs of solar energy production enough for it to compete with oil as an energy source.

“This is really a conceptual breakthrough, a new energy conversion process, not just a new material or a slightly different tweak,” said Nick Melosh, an assistant professor of materials science and engineering, who led the research group. “It is actually something fundamentally different about how you can harvest energy.”

30 Responses to “Solar Power Stepping Forward”

  1. Don’t hold your breath on this one. Lots of shoulda/coulda here.

    “The efficiency they achieved in their testing was well below what they have calculated PETE’s potential efficiency to be,”

    ” the actual efficiency of the process could reach up to the 50 or 60 percent the researchers have calculated.”

    Sounds like their funding is up for renewal.

    What’s the mechanism that makes the cesium enhance the conversion? Anyone have a copy of the paper?

  2. Steve Fitzpatrick said

    Interesting technical development, but not terribly relevant to solar power’s real limitation: you need a cheap and reliable way to store vast quantities of energy for when the sun doesn’t shine.

  3. Amabo said

    It’s called a magic box, steve. Duh.

  4. Amabo said

    On a more serious note, maybe a water pump that uses excess solar power to move water into a container, which can then be used during the evening and night to generate power, as well as an emergency water storage, which, if it’s high enough up, you wouldn’t need a pump to get to the tap. Not sure if that’s in any way feasible or economical…

    I know something like this is used for large scale power production complexes, although, if you have water catchments and power plants, why bother with solar…

  5. M. Simon said

    You not only have to store the energy. You have to have enough reserves to get you through 24 hours. The loss per hour can’t be high (less than .25% is a typical goal for rotating storage). The storage shouldn’t wear out too fast. And BTW 48 hour storage would be much better (and your loss rate would have to be better too).

    And in the winter it would be good to be able to collect 24 hours worth of power in 4 hours. Which means you might have an over production problem in summer. Except on cloudy days.

    And adding a steam plant to collect another 5% to 10% of the incident energy is going to cost. Esp if the steam generator doesn’t work at night. That is where storage comes in.

    Jeff you are right about a 10 to 20 year development cycle for the cells. I think storage is more like a 50 year job. Esp since so little effort is going into it.

  6. M. Simon said

    I forgot: diamond is the semi-conductor material of the not too distant future. It is a high temp material. About 400C to 500C operation is contemplated. With higher temperature storage you might be able to store thermal energy for overnight use.

  7. TimG said

    The cost is the labour not the panels. For example a new 1500 sqft asphalt roof will cost $1500 in materials but $6000 installed.

    The cost of labour does not follow moore’s law.

  8. A Semiconductor guy said

    This looks like a GaAs type cell with a Schottky contact to collect thermally excited electrons at the rear side. Note: it is for concentrators (ie big parabolic mirrors) not for large panel installations on houses and buildings as a local power source. It will not be a cheap device as it is III-V based. It may have promise but will be for big installations placed in sunny climes (ie death valley). Many distribution issues and storage issues to solve as well as cooling reliability concerns. Schottky contacts have been used for IR sensors before as have multiple junction diodes to try to capture a larger range of wavelengths.

  9. MarkP said

    I’ll be impressed precisely when improvements like this show up in a panel I can buy. I see “big solar improvement” stories every 6 months, but haven’t seen those lab improvements show up in over-the-counter PVs.

  10. ianl8888 said

    Posts #2 and #5 above describe the problem accurately – energy storage for night use. Most houses are relatively empty during daytime but require baseload power from about 5:30-6pm

    Storage batteries have been intensively R&D’ed for about 200 years now, with the world’s smartest chemical engineers working on this issue. A viable solution for domestic use is an economic holy grail, so motivation is intense … but no successful solution has been marketed for the bulk of the population

    I agree that water heating by solar power during daylight should work if the heated water is adequately insulated for next-day early morning use and the initial capital cost is not prohibitive. Again, pumping the water supply to domestic houses in the first place requires reliable baseload power

    Imagining that the populace can be told by decree to use only 2 light bulbs, take 2 minute showers, boil only 2 minute eggs, throttle heating/cooling during winter/summer and restrict TV to 2 hours/night is simply naive. U-Tube and Facebook would take a hit, too, with restrictions on PC hours and internet use 🙂

  11. Pops said

    Go nuclear.

  12. Jeff Id said

    Storage is the key. Most definitely. I wish people got this. In the meantime, go Pops.

  13. Geoff Sherrington said

    The other fundamental problem is the low energy density of sunlight.

    In pure physics, where does “light” capture leave off and “heat” capture begin? I imagine they are talking simply about a device that captures more of the IR, up to say 15 microns. This is possible now, but the incremental gain in efficiency offsets a tiny part of the gross cost of the installation. As noted above, labour costs and Moore’s law.

    There will always be niche markets for solar, but let’s not overdo their importance in the grander scheme. After all, they work on much the same radiative principles as greenhouses gases, so to glorify one while you demonise the other sounds a bit illogical.

  14. MikeH said

    Another major solar power discovery announcement that ignores/defies economic analysis. Yes, scientists and engineers will develop new solar energy capturing techniques. No, they won’t be economic because the instantaneous energy from the sun per square meter arriving on planet earth will not be able to be competitive against oil nor nuclear power sources since those sources have captured tens of millions of years of solar energy in nice little packets of mass that are cheaper to get at and cheaper to use.

  15. Brian H said

    Right; the operating temperatures and size are critical.

    But I hope a year or so from now the whole issue will be moot. 😀

  16. harrywr2 said

    “The process, called “photon enhanced thermionic emission,” or PETE, could reduce the costs of solar energy production enough for it to compete with oil as an energy source.”

    Almost no-one uses anything other then waste oil to generate electricity. So I’m not particularly impressed that solar could be economically competitive with a source of energy that isn’t economically competitive.

  17. R T Barker said

    When talking about promising technologies and what could be achieved with energy sources, it is hard to beat nuclear power for electricity generation.

    Since the 1970’s, when just over 100 nuclear powerplants had been built in the U S, a tangled web of laws, regulations and restrictions has been created which serve to inhibit the further deployment of nuclear powerplants in this country.

    What could be done with a positive attitude toward nuclear power in this country? Our total baseload power requirement could be satisfied by 200 to 300 more nuclear power units and that would mean lower electricity costs for everyone.

    Still talking about what could be achieved if we wanted to, we could have substantially lower investment costs per nuclear unit primarily from labor efficiencies in site construction, unit production and installation. Taking advantage of the learning curve with a production run of that size would make nuclear plants the hands down investment choice.

    Without the self-imposed constraints we currently seem to accept, recycling of muclear fuel would allow a vastly more efficient use of this resource and alleviate storage concerns in the process.

    I do not have any finanical interest in the nuclear industry but I sure could use lower electricity bills and if coal is a no-no, nuclear is my only chance..

  18. Bob Koss said

    All these improvements relate to cells in pristine condition. With snow, leaves, and other detritus accumulating on the cells it might be a good way for chimney-sweeps to expand their services. Sounds like maintenance will be an ongoing cost.

  19. Al Fin said

    People want to root for solar, but it isn’t realistic, and it won’t be realistic for a long time for reasons already mentioned. For anything bigger than a summer cabin, nuclear will be superior.

    As for those who doubt the ability of biomass to be productive enough for significant conversion to plastics, high value chemicals, fuels, etc etc, they are in for a big shock.

    Biomass to hydrocarbon conversion won’t replace petroleum, coal, or gas anytime soon. But by 2020 the idea of “peak hydrocarbons” is going to look even more absurd than at present due to renewable hydrocarbons, plastics, rubbers, chemicals, etc from biomass.

  20. Kan said

    Steve Mosher once asked something like, if you were around in 1850 looking forward to the industrial revolution would you predict that emitted CO2 would raise the earth’s atmospheric temperature, and how much.

    Well, lets try this question: We are looking forward to the solar revolution, how much will the earths surface temperature (I am talking blackbody here) drop with, lets say 25%, of all electricity generated for solar?

    And how long before we start saying uh-oh?

  21. Pops said

    #18 Bob: I sometimes think maybe part of the Progressive plan for full employment includes cleaning solar panels (along with the manual farm labor that will be required in the absence of fuels, fertilizers, herbicides, and pesticides). It won’t pay well, but at least everybody will have a job.

  22. Steve Reynolds said

    They seem to be trying very hard to not call this what it is:
    A vacuum tube solar cell!

    Also not new in principle. Einstein first explained the photo-electric effect.

    Still, this could have promise in the concentrator applications they describe.

  23. DeWitt Payne said

    Re: Al Fin (Aug 4 16:39),

    A million tonnes of algae sounds like a lot until you do the math. If the algae were 50% oil, a very optimistic figure, a million tonnes would be equivalent to 3.6 million barrels of oil. That’s only 4% of one day’s production of crude oil. How many days did it take to grow that million tonnes and how much area? And of course it’s worse than that because collecting and refining algae into usable oil will take significant energy, not to mention the production and distribution of nutrients for the algae.

  24. Brian H said

    Ugh. Numbers. How uncouth. How could you? ;p

  25. Bruce of Newcastle said

    Storage. This is a really difficult problem. If we’re talking batteries I can say it cannot be lithium ion, NiMH or lead acid batteries because there’s not enough lithium, nickel and lead in the world. So the prices would rapidly rise until those types of battery became uneconomic.

    Maybe sodium-sulfur, since these elements are common, but my experience of the sulfur market suggests even it might be a barrier to widespread use. Then there are the small problems of cold-start (Na-S needs to be 200 C or so to work) and explosions.

    Stored electrolysis hydrogen seems a possibility, but again there are those pesky explosions.

  26. Chris in OZ said

    250 million years ago, solar energy was stored in Queensland and the process lasted 150 million years. Today, the coal reserves in the Burnett Basin alone are estimated at 160,000 cubic kilometers. Australia’s total coal reserves, at the current world usage, would last 4000 years. Natural gas in Australia has been defined as “inexhaustable”. Google “Queensland coal reserves” (Queensland Government web site) Also google “Australia’s natural gas”

    So why mess about with solar panels, use more energy to manufacture than they produce, when there is plenty of solar energy in the ground stored up in black lumps.

    By the time the coal and gas runs out, we should be well on our way to supplying electricity from necular fusion power plants.

    BTW. There is about 2000 years of iron ore in the ground here too !

  27. RuhRoh said

    Hey Jeff;

    The last time I checked, it was necessary to expend roughly 5 years of the eventual output of a solar cell just to fabricate the polysilicon, and this may have been relying upon Si by-product of single-crystal silicon for electronic use.

    I had the impression they were tending toward optimistic assumptions such as the cleanliness of the optical surfaces, etc., to get the number down to 5-7 years ‘energy-payback-time’.

    And how is that 5years worth of electricity being generated?

    By Coal-Fired Generators in China!

    At least they aren’t expected to limit their CO2 emissions to enable it here.

    Am I wrong on this?
    Did anything miraculous happen while I wasn’t watching?

  28. Brian H said

    There Ain’t No Such Thing As A Free Erg!

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