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Artificial Leaf Could Provide Cheap Energy

Posted by Soulskill on from the make-like-a-tree-and-catalyze-the-electrolysis-of-water dept.

sciencehabit was one of several readers to tip news of a sunlight-harvesting artificial leaf, writing: "Nearly all the energy we use on this planet starts out as sunlight that plants use to knit chemical bonds. Now, for the first time, researchers at the Massachusetts Institute of Technology have created a potentially cheap, practical artificial leaf that does much the same thing—providing a vast source of energy that's easy to tap. The new device is a silicon wafer about the shape and size of a playing card coated on either side with two different catalysts. The silicon absorbs sunlight and passes that energy to the catalysts to split water into molecules of hydrogen and oxygen. Hydrogen is a fuel that can be either burned or used in a fuel cell to create electricity, reforming water in either case. This means that in theory, anyone with access to water can use it to create a cheap, clean, and available source of fuel."

51 of 326 comments (clear)

  1. Vaporware by GabriellaKat · · Score: 5, Funny

    At last, true vaporware!

    --
    "Have you ever thought about just turning off the TV, sitting down with your politician, and hitting them?"
    1. Re:Vaporware by georgesdev · · Score: 2

      today's dilbert strip matches this post perfectly: http://www.dilbert.com/strips/comic/2011-03-29/

  2. So it's a solar cell.... by artor3 · · Score: 4, Insightful

    There's only so much insolation to harvest. If this is cheaper and higher efficiency than existing solar cells, then great. Based on the article, it's only 5.5% efficient, so meh. But even if it were 100% efficient, it's not some magical free energy machine, and never can be. While it's true that "nearly all the energy we use on this planet starts out as sunlight", a lot of that energy arrived at earth several millenia ago. In the long run, we're going to need to either use less energy (preferably by making things more efficient, not making do with fewer things) and/or get some near-unlimited fuel source, like fusion.

    1. Re:So it's a solar cell.... by timeOday · · Score: 5, Insightful
      No, actually there is plenty of sunlight to power all current needs and more, if we could capture it efficiently.

      Yup, I linked to a page claiming to "debunk" this "myth" on the basis it would take a solar panel the size of Georgia to power the whole earth. Big deal! Vastly more land is consumed by agriculture. Just reclaiming all the space on rooftops, roadways, and parking lots for solar would account for a lot of that, puttng power generation right where it's needed.

      And then there's there's the 2/3 of the earth covered by water nobody is making much use of. If cheap solar devices can produce hydrogen, it can be shipped long distances efficiently.

    2. Re:So it's a solar cell.... by Gerzel · · Score: 2

      The big question I see with this is just how clean does the water going in have to be?

      Sunlight is free, but clean water is not.

    3. Re:So it's a solar cell.... by maxume · · Score: 2

      That's just silly. The sun blasts the earth with petawatts of energy, we only need to harvest terawatts, the problems are all in cost, efficiency and storage, not in availability of energy.

      --
      Nerd rage is the funniest rage.
    4. Re:So it's a solar cell.... by yeshuawatso · · Score: 2

      Sunlight "falls" from the sky every day...

      Try telling that to Beijing!

    5. Re:So it's a solar cell.... by by+(1706743) · · Score: 2

      ...and/or get some near-unlimited fuel source, like fusion.

      That's what solar power is -- it's just that the fusion source is millions of miles away.

      Additionally -- and I'm sure this is redundant with some other posts -- producing hydrogen directly cuts the middle man, if that's what you're ultimately going to do. I'd certainly rather putter around in one of these or one of these than in an electric vehicle -- and if the energy's cheap and clean...well, bring back the muscle cars, I say!

    6. Re:So it's a solar cell.... by haruchai · · Score: 2

      So far, they've tested using water from the Charles River, presumably unfiltered. Next they'll try using seawater. Stay tuned.

      --
      Pain is merely failure leaving the body
    7. Re:So it's a solar cell.... by bunratty · · Score: 3, Interesting

      Well, at the point solar power runs out, we'd have to find a new planet anyway. It would provide energy for billions of years rather than hundreds. For all intents and purposes, solar, wind, and biofuels never run out.

      Also, all forms of energy generation require human workers. Who do you think digs up the coal, oil, and uranium? Who do you think runs the oil refineries, nuclear power plants, and coal plants? Do you have any evidence that we'd need more workers per unit of solar power than for other forms of power?

      --
      What a fool believes, he sees, no wise man has the power to reason away.
    8. Re:So it's a solar cell.... by rubycodez · · Score: 4, Informative

      Actually, the deuterium in the oceans would provide fusion energy sufficient for billions of years, the sun would scorch the earth to by expansion first before we ran out. And there is lithium and boron, and we can make tritium. Fusion really is the holy grail of power generation if we can't make solar power work. http://www.engineeringchallenges.org/cms/8996/9079.aspx

    9. Re:So it's a solar cell.... by currently_awake · · Score: 2

      1- You can't ship hydrogen cheaply or efficiently. 2- the biosphere (fish) like having sunlight on the ocean. 3- distributed energy is too hard for rich people to profit from, they prefer centrally generated power, with metering.

    10. Re:So it's a solar cell.... by sunzoomspark · · Score: 3, Informative

      The big question I see with this is just how clean does the water going in have to be?

      The article said they'd been running it on water from the Charles River, so it doesn't have to be very clean.

    11. Re:So it's a solar cell.... by rubycodez · · Score: 3, Informative

      Deuterium is much more abundant than gold and far easier to extract from water (of any source, fresh or ocean doesn't matter). We've been producing and using deuterium for decades, for example as moderator in heavy water reactor. The energy cost is negligible even for fission reactor moderator, for fusion energy even smaller cost compared to yield.

    12. Re:So it's a solar cell.... by rubycodez · · Score: 4, Interesting

      Normal solar panels have albedo of 0.35, which is close to average of earth 0.30. We'd be far better off thermally using that than burning fossil fuel or fissioning atoms. However, comparing the energy input of the sun to what man generates, the fraction is so very tiny that the global direct thermal effects (not greenhouse gases which is another discussion) of our power generation in essentially zero.

    13. Re:So it's a solar cell.... by c6gunner · · Score: 3, Interesting

      Well, at the point solar power runs out, we'd have to find a new planet anyway.

      I was more concerned about the materials which go into panel production.

      Also, all forms of energy generation require human workers. Who do you think digs up the coal, oil, and uranium?

      The same types of people who dig up the materials needed to make your panels?

      You'd need more resources (ergo, more people working) to build the damn panels in the first place, and THEN you'd need to hire tens of thousands of workers to service the panels. There's a reason why solar power is currently THE most expensive source of energy on the market, and is between 2 and 3 times more expensive over the lifespan of the panels when compared to nuclear (and 4-6 times more expensive than oil/coal).

      Do you have any evidence that we'd need more workers per unit of solar power than for other forms of power?

      You know, I had a really long comment written up, with figures showing you'd need upwards of 10,000,000 man hours to do a single cleaning, and extrapolating that to X number of full time workers and comparing it to number of workers needed to run a nuclear power plant .... but then I went and checked and it turns out solar panels don't need to be cleaned all that often. So, suffice it to say, I don't have any solid figures, and I don't think anyone else does at this point. We'd have to figure out a mean rate of failure, which would be different for different panel types, AND we'd have to figure out how often they need cleaning, which would be different for each area. You'd also have to worry about unexpected things, like tornadoes and other extreme weather (which don't generally affect nuclear power plants), and you'd have to worry about man-made problems, like Billy Bob and his cousin Cletus figuring out that there's millions of free panels sitting there for the taking. I'd say that it's fairly obvious that they would, at the very least, require a similar number of personnel as other forms of power generation, but I suspect the number would be far higher.

    14. Re:So it's a solar cell.... by barv · · Score: 2

      You are wrong, there is plenty of sunlight energy to harvest...

      Sunlight provides 1 KW/M^2. The USA uses about 4 trillion KWH per annum (see CIA's world factbook), which is about 10,000 KWH per person per year, or 30 KWH/day/person. Assume 20% efficiency, and 5 hours of sunlight each day, then 30 M^2 of solar collectors needed per person. Hmm the average house is about 2-3 times that, and has 2-3 people.

      Or look at it another way, a square mile is about 250,000 square meters, and would produce 100,000 KWH in a four hour day, or 40 million KWH in a year. So an area 100 miles square somewhere in NM or AZ could produce all the power currently used by the USA. You could buy a sheep station that size in Australia for $10 million.

    15. Re:So it's a solar cell.... by ross.w · · Score: 2

      Well, we could burn a whole bunch of coal to create extra CO2. That would form a barrier to block the escaping energy - like a big greenhouse... Oh wait...

      --
      If my call is important, why am I talking to a recording?
    16. Re:So it's a solar cell.... by ptbarnett · · Score: 2

      I think it can be traced back to Ronald Reagan ripping off the solar powers placed on the White House by his predecessor, as if they were an abomination in the eyes of god.

      You discredited your entire posting with a bogus claim that can easily be refuted:

      White House Will Not Replace Solar Water-Heating System

      The panels of the system had been dismantled to fix the roof underneath. Dale A. Petroskey, a White House spokesman, said Friday, ''Putting them back up would be very unwise, based on cost.''

    17. Re:So it's a solar cell.... by Anonymous Coward · · Score: 3, Insightful

      People keep claiming that something the size of Georgia is a sane amount of the earth's surface to cover. You know that agricultural land isn't completely covered with manufactured material, right? Even if it were, how is doubling the human footprint on the planet reasonable? That article really is a successful debunking.

      You're talking about mining enough resources to cover Georgia in something manufactured every N years, perhaps N = 30. Think about how bad that is. It's not road bed, either, it's something expensive and chemical-intensive to produce.

      I'm completely for solar energy research, and it can totally make sense for some applications, and why not cover an otherwise unused roof when solar cells are cheap enough. But you just have to look at the energy densities of various energy sources to understand that nukes are it. Nukes are much more sustainable than anything that requires to cover 0.01% or more of the earth's surface with anything manufactured. Nukes aren't perfect, but they're by far the most sustainable, safest, cheapest source of energy, if we could ever act rationally as a species.

      I mean, energy density (http://en.wikipedia.org/wiki/Energy_density) isn't the whole story, but even the most pedestrian nuke fuel is four orders of magnitude denser than the most exotic chemical fuel. Five would be a realistic comparison, and then another order of magnitude for more refined fuel, and then another three orders of magnitude when fast breeders become really practical. We're talking about eight orders of magnitude denser energy!

      Uranium isn't cheap to mine, but it almost doesn't matter, and silicon is not so cheap to refine, either.

      So, I'm no expert, and I'm happy to hear some detailed arguments refuting my back-of-the-envelope ones. But even the most cursory glance at the issue from an engineering perspective says nukes are quite safe enough to be the most sustainable form of energy, even if you use TMI technology and just blow up a nuke plant every 10 years. The energy density, and therefor logistical considerations, are just ridiculously lopsided.

      Again, I'm all for developing everything, and I'm working hard on residential-scale solar myself as a hobby. But basic physics says there will not be a fairytale ending for solar, wind, biofuels, or fossil fuels. Certainly, there will be local niches where each of these will be the right tool for the job, but at the planetary scale, we can do better than evolution. We have harnessed the power of the atom. WTF is wrong with us.

    18. Re:So it's a solar cell.... by joocemann · · Score: 4, Interesting

      You should consider:
      1) The energy harvested by solar would hit the earth anyway, and thanks to laws of thermodynamics, we can't get 'more' from it than would already arrive.
      2) The energy harvested using fossil fuels hit earth millions of years ago and was stored in chemical bonds that we break with combustion. If we otherwise did not choose to release this energy via combustion, it would stay in chemical form.

      There is a difference. There is also no excess blanket of CO2 being produced, where carbon that has been absent from the atmosphere for millions of years is now reintroduced, and as it is a heat storing gas, it aides in global warming.

      There is a difference.

    19. Re:So it's a solar cell.... by similar_name · · Score: 2

      There's only so much insolation to harvest.

      From my understanding that's quite a bit. I don't think we're going to cover the planet in solar panels but still. As long as the energy required to make a panel/leaf/etc. is less than the energy produced over the lifetime of the panel/leaf there is a benefit. How much benefit and how it can be used may be a matter for debate but it shouldn't be dismissed out of hand.

      But even if it were 100% efficient, it's not some magical free energy machine, and never can be.

      Why? At 100% you would be getting nearly 100 watts out every square foot. A 150 square foot car port could capture 120kWh in 8 hours. An electric car can get get 100km for every 10-23kWh. Even with only 10% of that energy an efficient EV would get 100 km or 60 miles of 'free energy' each day. While this isn't a complete energy->transportation solution for everyone it would probably work for most of the earth's population. In a grid system those that drive less sell their extra watts and those that drive more buy them. Even if you drove 200 miles per day you'd get nearly 1/3 of those miles for 'free'.

      While it's true that "nearly all the energy we use on this planet starts out as sunlight", a lot of that energy arrived at earth several millenia ago.

      It's still arriving so why shouldn't we be able to use it. Now it may be that fossil fuels are accumulated over time but I doubt the process for turning solar energy into fossil fuels is/was very efficient.

      In the long run, we're going to need to either use less energy (preferably by making things more efficient, not making do with fewer things)

      Don't forget most of the planet is undeveloped so using less energy is a pretty tall order. No matter how efficient you make a refrigerator it will still use more energy than not having one. The same goes for the distribution of goods, resources and services that are required for societies to develop.

      and/or get some near-unlimited fuel source, like fusion.

      Like the sun? Not to be pedantic but it seems your dismissing solar as ever being a viable source of energy and at the same time proposing that one of the solutions is to create an energy supply like the sun. BTW I would like to see advances in fusion as well.

      If this is cheaper and higher efficiency than existing solar cells, then great. Based on the article, it's only 5.5% efficient, so meh.

      Except for the 'meh' I think this is the least 'biased' against solar as an energy source. I hesitate to say biased but I'll admit I'm biased towards all energy sources. I believe we as a species need more energy and we need a lot more. Efficiency is important but supply is more so.

      I'm not saying solar is OMG Ponies! but it is an impressive source of energy and we tap such a tiny part of it. There is so much solar energy that if these are cheap then a 5.5% efficiency could be enough to make them useful. If anything I would argue that using solar to directly make hydrogen means you are probably going to take a 60-70% loss if you turn that hydrogen back into electricity or burn it. That's a pretty big hit on that 5.5% capture, so you probably won't want these on your car port :). However, if you specifically need hydrogen it may compare to taking a 'normal' solar panel and using electrolysis.

    20. Re:So it's a solar cell.... by PopeRatzo · · Score: 2

      Maybe you don't remember the Reagan presidency as clearly as I do, but he was a president who was keenly aware of the symbolic meaning in every single thing he did.

      Every single president makes small but symbolically important changes when taking over the White House. I believe there was a clear sub-text in the act of dismantling those solar panels. Remember, not long before there had been a serious disruption in the oil supply so there was a great deal of talk about "breaking America's addiction to oil". I believe Reagan was making a very clear statement in his act, that there would be none of that "renewable" stuff under his watch. It was a message to the oil companies and a message to the American people that conservation was unnecessary and indeed somewhat un-American. That solar power was for hippies and technocrats and the White House would burn fossil fuels unapologetic-ally, thank you very much. Reagan's Secretary of the Interior went to work immediately to sell off public lands for oil exploration, mining and the cutting of old-growth forests. Remember James Watt?

      It's worth mentioning here that Reagan's predecessor, Jimmy Carter was in charge of a team during his naval career (early 50's) that went to assist in shutting down the Chalk River nuclear reactor after it suffered a partial meltdown. About a year earlier, Ronald Reagan was in Hollywood starring in Bedtime for Bonzo, playing Professor Peter Boyd, a professor who used a lab chimp to prove that environment trumps heredity. I understand it was a work of fiction.

      I wonder what would be different today if he had continued with a focus on energy efficiency and conservation that his predecessor started.

      --
      You are welcome on my lawn.
    21. Re:So it's a solar cell.... by AmonTheMetalhead · · Score: 2

      There's still the little problem of efficient energy storage. You could outfit every home in the world with solar panels and have a huge capacity on a sunny day, but you still need power at night, storage still is an issue. As for the technology discussed here, it splits water into hydrogen, a highly flammable gas, storing this in a safe manner might also be problematic (i'm not a chemist, so i might be wrong)

  3. 5.5% of the energy in sunlight into hydrogen fuel by Culture20 · · Score: 2

    Ooo, 5.5%. And it's *potentially* cheap!

  4. This is how it goes by alex_guy_CA · · Score: 4, Insightful
    See cool science article.

    Get excited.

    Read comments.

    Excitement crushed.

    --
    San Francisco Photographers
  5. MIT invents everything by RabidRabbit23 · · Score: 3, Informative

    I saw a presentation on exactly this technology a few years ago at a conference, not from an MIT researcher. It's a strange phenomena, but within science MIT is just one of many research institutions doing great work, but to the public it has the most significant and frequent press releases. I mean, this isn't even a leaf, it's a silicon wafer which happens to be green and splitting water using catalysts is very old. The only innovation I'm seeing here is a new catalyst, which is pretty common in these fields. I also like the token quote from Bob Grubbs who won a Nobel prize in catalyst research and thus is interviewed in every catalyst article.

    1. Re:MIT invents everything by Rakshasa+Taisab · · Score: 2

      "Only invention here is a new catalyst"?

      I would not be so quick to downplay the significance of finding a _CHEAP_ catalyst, when platinum was what was used before. That's pretty damn significant if it means mass-produced wafers costs plummet.

      --
      - These characters were randomly selected.
  6. Benefit to Georgia by Anonymous Coward · · Score: 4, Funny

    Plus as some one who lives in Georgia I can tell you that is is hot! A solar shade for the state might work well!

    1. Re:Benefit to Georgia by Sulphur · · Score: 2

      What's so great about Savannah?

      When Sherman reached Savannah, he realized that if he burned the city, then he would have to sleep in a tent.

  7. 10x more efficient than photosynthesis?! by wisebabo · · Score: 2

    According to a similar article in science daily http://www.sciencedaily.com/releases/2011/03/110327191042.htm it is 10x more efficient than (natural) photosynthesis.

    I'm amazed that the foundation of life on earth is so inefficient (one tenth of 5.5% is only .55%!). Is this right? If it is then I'm glad our solar devices may not have to cover up too much of our planet to generate the energy we need (but if we ever develop solar powered self-replicating nano-bots, they will totally out-compete the natural biosphere).

    Also, if this is true, then isn't this a major reason against using biofuels? I mean in addition to this inefficiency of photosynthesis, you've still got to convert it into some sort of fuel (but I guess the same is true of this artificial leaf; hydrogen is not the most practical of fuels). I guess maybe biofuels are still in the running because they can be "manufactured" very cheaply (farming and fermentation) with thousands of years of technology developed. (Or maybe it is the politics of the farming lobby).

    (I'm also amazed that they used water from the Charles river in Boston and that it still worked. I remember a time when an accidental dunking in the none-too-clean river meant a quick trip to the doctor's office for shots!)

    1. Re:10x more efficient than photosynthesis?! by loshwomp · · Score: 4, Informative

      I'm amazed that the foundation of life on earth is so inefficient (one tenth of 5.5% is only .55%!). Is this right?

      Somewhere on that order, yes.

      Also, if this is true, then isn't this a major reason against using biofuels?

      Exactly. Plants are ~1% efficient at harvesting solar energy, and we have much better collectors (photovoltaics) that are much more efficient (15-20% in mass production) and generate energy in a more versatile form (electricity).

    2. Re:10x more efficient than photosynthesis?! by Anonymous Coward · · Score: 5, Informative

      Plants limit their photosynthetic efficiency largely because raising it too high starts raising the internal temperature, which raises the rate at which they lose water. Basically, they are tuned to gather 'enough' energy without wasting water (which is rarer for them than sunlight) rather than extracting as much energy from the sun as they can. Biofuels are usually suggested not because they are efficient, but because they are cheap and work fairly well with our existing infrastructure.

    3. Re:10x more efficient than photosynthesis?! by yndrd1984 · · Score: 2

      they are tuned to gather 'enough' energy without wasting water (which is rarer for them than sunlight)

      True. Except for the plants that grow in rain forests, or the ocean, or lakes, or swamps, or rivers, or ...

  8. Isn't it better with traditional electrolysis? by Jason+Pollock · · Score: 2

    According to wikipedia, http://en.wikipedia.org/wiki/Electrolysis_of_water , traditional electrolysis is 50-80% efficient, and solar cells are ~20%.

    http://en.wikipedia.org/wiki/Solar_cell_efficiency

    Therefore, the efficiency of using the solar panel to power electrolysis would be .2*.5 -> .2*.8 = 10% -> 16%, wouldn't it?

    So, unless there's a pretty substantial price benefit to the cell, where's the benefit?

    1. Re:Isn't it better with traditional electrolysis? by im_thatoneguy · · Score: 3, Informative

      It's made from copper and cobalt instead of a lot of the more exotic materials used in standard photo-voltaic cells.

    2. Re:Isn't it better with traditional electrolysis? by loshwomp · · Score: 3, Insightful

      So, unless there's a pretty substantial price benefit to the cell, where's the benefit?

      As you have discovered, the economics are precisely the key to solar energy. The power density (Watts/m^2) is unimportant, except for installations with unique constraints (e.g. spacecraft). For terrestrial applications, Watts/$ is the most interesting term.

      Similarly, for economic reasons, I don't think electrolysis (or H2) is likely to succeed on a wide scale. The dirty secret of the H2 "economy" is that the hydrogen fuel cell cycle has a round trip efficiency of about 25%. A fuel cell is effectively a battery, and we already have substantially better batteries at a tiny fraction of the cost.

  9. wonder what the 3 metals are? by slew · · Score: 2

    Yesterday, Nocera reported devising a cheap catalyst that uses three different metals to form H2, getting around the platinum problem. Nocera didn't reveal the makeup of the new catalyst, as the work is not yet published, and he is in the process of patenting it.

    Before we get too excited, apparently most of his research to date has been with cobalt, phosporus, tungstun and rhodium. Not sure where all this stuff comes from, but hopefully it is widespread enough won't turn into another middle east problem.

    Also, at 5.5% efficiency, we would probably need quite a bit of this stuff which may cause some environmental issues by itself (mining, industrial polution, etc).

    As a side note, many people talk about cutting back on petrol consumption as doing our part to reduce the demand for oil which comes from the problematic middle east, but I rarely hear of folks cutting back on electronics "toy" consumption to reduce the demand for coltan (the ore where much of the tantalum for capacitors comes from) which is causing huge problems for countries like the republic of congo. Haven't heard much about the coltan topic on /. Just be cause it's "electronic" and doesn't use oil doesn't mean it's better when scaled to industrial quantitites.

    Not saying this proposed "artificial leaf" technology could definitly cause this kind of natural resource scarcity/extraction problem, but the sad fact is that if this becomes industrialized, it may not be much better than what we have today and most folks aren't even aware of the problems we have today (or even care).

  10. no free energy by v1 · · Score: 2

    When you start talking about that scale, even solar is no longer free. All that sun, hitting the land or the sea, you don't think that energy is otherwise "wasted" or destroyed? It goes to heat the earth. If you capture it with solar panels or other methods, that energy never gets where it was going.

    I don't have any good idea what the impact of that is, but you can't just discount it as "free".

    --
    I work for the Department of Redundancy Department.
    1. Re:no free energy by Black+Gold+Alchemist · · Score: 3, Informative

      If you have solar panels capture the energy, they simply suck the energy up, store it, and when it returns as heat in the friction of the objects it moves, the lights it powers, etc. Without the solar panels, the light would just be heat. So it is free.

      --
      Responsibility is an addiction
      Virtue is a temptation
      Community is a cartel
    2. Re:no free energy by shermo · · Score: 4, Insightful

      The second law of Slashdot:

      "No matter how obvious you make the joke, someone will feel the need to correct it for you."

      --
      Insanity: voting in the same two parties over and over again and expecting different results
  11. What about night and bad weather? by jklovanc · · Score: 2

    There is not an energy production problem there is an energy storage problem. Almost all green sources of energy have have down times. In the case of solar energy that is night. If we could store some of the energy produced in the day we would be much further ahead. There is some research and a few test being done but energy storage is not as "sexy" as energy production.

    1. Re:What about night and bad weather? by jklovanc · · Score: 2

      How big do you think a battery would have to be to supply electricity to New Your City for 8 hours at night? Batteries are not a viable solution for storing power on a large scale.

    2. Re:What about night and bad weather? by jklovanc · · Score: 2

      How many of these storage devices have been made or even planned? The technology exists but has not been implemented on a large scale. I know of very few. You also forgot about flywheels and compressed air storage.

      The raised water technology works great in the mountains but what about Kansas? Also you require space for two large reservoirs. How many valleys to we loose to energy storage? It also requires three separate sets of machinery that need to be built and maintained. All that equipment costs money and increasing the cost of energy produced. Pointing at at technology as a solution and implementing it is a very different thing.

      I go back to my main issue with most "green" energy; what do you do at slack tide, at night, in the middle of a storm? Under those conditions there is no tidal power, no solar power and no wind power (all turbines have a max wind speed).

    3. Re:What about night and bad weather? by LBU.Zorro · · Score: 3, Informative

      Ok, so I found 3 Humboldt Countys in California, Iowa and Nevada, but based on size it appears you mean the CA one, of course it only really has 2.2million acres of land, the rest is water.

      According to this report (http://postcarboncities.net/humboldt-county-ca-energy-element-background-technical-report) Humboldt county (apologies if I got the wrong one or anything) used 940 GWh of electricity alone in 2003, which comes out to around 2500MWH averaged daily - that is a heck of a jump from your 100MWH, 25 times as much. And that doesn't count usage growth over the last 8 years, nor the natural gas heating, cooking and hot water (about 45million therms) nor transportation energy costs.

      I'm pretty concerned by your numbers now, but even taking your 25 acre 5MW station at face value, and even allowing that it's a molten salt plant and stores enough energy to provide that 5MW continuously day and night with backup storage to last several weeks and to provide that 5MW during the local solar minimum you would need 12500 acres to provide just the electrical energy. 10 cubic meters of molten salt can provide 1MWH of storage, since you'd need 2500MWH of storage for a single day, and several weeks of storage you're talking about 350k cubic meters of molten salt, a heck of a lot.

      Sure all of this is relatively minor compared to the actual size of Humboldt county but I'd guess the cost of manufacture of a 5MW plant to be around the $20million mark (unaccurately based on http://www.power-technology.com/projects/Seville-Solar-Tower/ and scaling down), so if you have to build 500 of them just to handle the electrical load you're talking about $10billion to manufacture (and remember this is for purely the electrical generation of 2003, not transport or natural gas). The population of 2008 is estimated at about 130k (http://mapzones.org/Humboldt_County_California.html) meaning that would cost about $77k per resident. The same report shows that the average per-capita income of Humboldt county residents is $17k annually - or 4.5 times the cost.

      I don't know about you but I'm a little puzzled as to how you're going to pay for all of this? Not to mention over doubling it for powering hydrogen/electrical vehicles and replacing natural gas completely - something you'll have to do to have this green revolution of yours.

      What you, and everyone who thinks that "popular pundit b.s." is just "b.s." seem to fail to understand is that this is a huge engineering, financial and technological issue to overcome. There are many reasons why it hasn't happened already, and aside from energy density and reliability the biggest reason is cost, are you really willing to have an additional 50% tax on all income in your state for the next 10 years to pay for constructing the plants necessary? Think of what that would mean, can you cope with 50% less money every payday?

      Just as a comparison a 320MW natural gas power station costs about $150million dollars (http://www.power-technology.com/projects/laverton/), so you're looking at about the equivalent of 8 of them, or $1.2billion dollars - your solar plan is an order of magnitude more expensive. If you're saying that they should be built with loans and then amortised over the lifetime of the plant with the cost being the energy, you're still looking at about 5 times more expensive electricity (yes I know the fuel costs are minimal - mirror maintenance is a pain but you don't have to buy gas) unless you subsidise it somehow (in which case it's still 5 times as expensive but you're pretending it's not).

      If you're going to have statements like "Now you see where the science behind green makes sense, and the popular pundit b.s. that is constantly echoed is just exaggerated doubt and nonsense claims." then you had really better match that with actual verifiable numbers and facts. Rather than just repeating what you've heard without really understanding it - it is completely possible, but then again so

  12. Re:Orbit by currently_awake · · Score: 2

    A space elevator changes everything, but until then given the astronomical cost of getting anything into orbit it would be cheaper to just build a much bigger solar array with batteries on earth.

  13. Re:5.5% of the energy in sunlight into hydrogen fu by Solandri · · Score: 2

    Ooo, 5.5%. And it's *potentially* cheap!

    Photosynthesis in sugar cane is 7%-8% efficient and compared to this is practically free (needs water and land, but so does this). The stuff manufactures itself for crying out loud, we don't even have to invent nanomachines to construct it for us.

    The whole point of photovoltaic panels is that they convert the sunlight directly into electricity for our applications which need electricity. If instead you're going to convert the sunlight into a hydrogen-based fuel like this device, just plant some vegetation and convert its cellulose into alcohol-based biofuel and burn that instead. It's a helluva lot cheaper. The fuel is liquid at room temperature and 1 atmosphere, so is a helluva lot easier to store, transport, and handle than pure hydrogen. And even though burning alcohol fuels releases carbon, it's still carbon neutral since making it consumes the exact same amount of carbon from CO2.

    Unless you're in a weight-sensitive application like the space program, or they can get this thing's efficiency up to about 20%-40%, I don't see what the big deal is. Biofuels are much more practical than hydrogen for most applications.

  14. Re:5.5% of the energy in sunlight into hydrogen fu by lawpoop · · Score: 2
    It seems unlikely the hindenburg blew up due to hydrogen. Remember, hydrogen is very light, so if there's any rupture, the hydrogen will escape rather than hang around to explode. Sure, some will, but the vast majority will go straight into the atmosphere.

    That's why people buy the idea that the coating was what actually exploded.

    --
    Computers are useless. They can only give you answers.
    -- Pablo Picasso
  15. Re:Orbit by Jeremi · · Score: 2

    For solar power to work and be economically viable, it needs to be in orbit. Period. No solar cell, no matter how efficient is going to be viable under an atmosphere.

    You have it exactly backwards. Ground based solar power is economically viable now in many places, and will become more so as solar panel prices decrease, and the cost of non-renewable competition increases.

    Space-based solar power, OTOH, is a non-starter because the cost of launching solar panels into orbit is so much that you'd get a much better return on your investment leaving the solar panels on the ground. It doesn't matter how efficient the solar panels can be in orbit if it's impractical to get them there.

    A space elevator would change all of that, of course, and it would be all kinds of awesome.... but I wouldn't hold my breath on one being put up any time soon.

    --


    I don't care if it's 90,000 hectares. That lake was not my doing.
  16. Re:5.5% of the energy in sunlight into hydrogen fu by sl149q · · Score: 2

    Yes, but you then have to convert the sugar cane to something else (ethanol for example). So you have to look at how much energy you get out of the ethanol you get after you convert the sugar cane which you created with 7-8% efficiency.

    I suspect that if you are converting directly to a usable energy source at around 5% it would be fairly competitive and may require less steps (capture hydrogen, compress and store, versus grow sugar, harvest, then truck somewhere to a chemical plant to covert to alcohol etc etc.)

  17. Don't use this leaf when strapped... by surzirra · · Score: 2

    ...in the wilderness for toiletries, the results could be shocking.